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Abstract

The aim of the present study was to investigate the long-term and high-dose application of ketamine on the liver by employing histologic and biochemical methods. A total of 30 male rats were randomly assigned to control and four treatment groups (n: 6). Saline for control group and different doses of ketamine for four treatment groups (40, 60, 80 and 100 mg kg⁻¹) were administered intraperitoneal twice a day for 2 weeks. Immunohistological staining, light and electron microscopy were used to study tissue specimens. Histopathological changes were more severe and diverse in groups 80 and 100 mg kg⁻¹ day⁻¹, and the least significant change was observed in groups 40 and 60 mg kg⁻¹ day⁻¹. The most important ultrastructural changes were seen in mitochondria and in the rough endoplasmic reticulum. The immunoreactivity of calcineurin was determined as different. Prolonged use of ketamine caused hepatocellualar toxicity and histological changes in hepatocytes in a dose-dependent manner in all experimental groups.

Keywords

Hepatotoxicity ketamine

Introduction

Ketamine is a dissociative anesthetic and analgesic frequently used for different indications. This includes surgical anesthesia for pediatric patients, treatment of chronic pain and brief anesthesia requirements like wound dressing changes.^1
–3 Ketamine is also increasingly abused for recreational purposes. Ketamine causes sedation, anesthesia, analgesia, immobility and neuroprotection⁴; however, it has also known important side effects such as hypertension, hallucination, hyper salivation, confusion⁵ and fatigue. Furthermore, long-term usage of ketamine has been reported to cause apoptosis of neurons and cause urological abnormalities.^6
–8

Ketamine is extensively metabolized in the liver by microsomal enzymes into metabolites I and II (10%) and are excreted prominently in urine.^9,10 These metabolites and ketamines have been reported to damage hepatocytes and other cells of liver.^11,12 Ketamine also induces other metabolical effects that may be related to hepatotoxicity including changes in lipid metabolism in liver.¹³ Furthermore, ketamine has effects extending to the biliary smooth muscle causing biliary dilatation.¹⁴ Supporting this, recent clinical studies and case reports demonstrated hepatotoxicity of ketamine during chronic pain management.¹⁵

Calcium (Ca²⁺) is stored in the endoplasmic reticulum and plays an important role in cell functions including enzyme activities, mitochondria motility, morphology and metabolic processes. Studies demonstrated the important role of Ca²⁺ in liver cell death in primary cultures of hepatocytes.¹⁶ Mechanism of ketamine hepatotoxicity is unclear; however, ketamine administration decreases intracellular levels of calcium concentrations,¹⁷ which were linked with structural defects in stages of cytoskeleton remodeling and mitochondrial adenosine triphosphate synthesis.¹⁸ Calcium also regulates calcineurin (CN), a protein phosphatase that is expressed in many tissues.^19,20 CN activation has an antiapoptotic effect and causes hepatoprotection in liver.²¹ Therefore, it is plausible to assume that calcium and/or CN plays important role in ketamine-related hepatotoxicity.

There is paucity of studies focusing on potential toxic effects of ketamine on hepatocytes. The primary aim of the present study was to investigate the effects of the long-term and high-dose ketamine on rat hepatic cell morphology by the application of histopathological, electron microscopic (EM) and immunohistochemical methods. Secondary objective was to determine whether the blood level of blood Ca, glucose, magnesium (Mg), potassium (K) and some liver enzyme function tests were affected by different drug doses.

Materials and methods

This study was performed in accordance with the National Institute of Health Guide for the Care and Use of Laboratory Animals. The protocol of the study was reviewed and approved by the Experimental Instruction of Local Ethics Committee for Animal Experiments, School of Medicine, Rize University of Turkey (dated 31 May 2010, meeting number: 21).

Study design

A total of 30 adult Sprague-Dawley male rats weighing 275–300 g were used in this study. All animals were fed with a standard pelleted rat diet (Bayramoglu Yem, Erzurum,Turkey) and had free access to water for 2 weeks. The animals were housed under controlled conditions (22 ± 3°C, 50–60% relative humidity, 15–18 per hour air ventilation and 12 h light–dark cycles).

In order to determine the effects of ketamine on liver and blood chemistry, five groups (six rats in each group) were formed and treated for 2 weeks twice a day. Group I assigned as control group receiving 1 mL normal saline solution. Four doses of ketamine, 40, 60, 80 and 100 mg kg⁻¹, were set and each dose was assigned for one group. The drug was administered intraperitoneally twice a day for 2 weeks.

The blood samples were taken from the tail vein at the ends of every application for biochemical analysis. After 14 days, the animals were killed by decapitation and left/right part of their liver were immediately removed for fixation.

Tissue processing

Electron microscopy

Animals were fixed with intracardiac perfusion method by a heparinized saline (25 IU mL⁻¹ in 0.9% NaCl) solution followed by a mixture of 2% glutaraldehyde (150 mL) + 2% paraformaldehyde in 0.1 M phosphate buffer, pH 7.4 at room temperature, the remaining part of animals’ liver were removed and kept in the same fixative overnight at +4°C. The next day, waited for 1 h with 1% osmium tetroxide (OsO₄) in buffer for postfix (at +4°C), after treating with dehydrating through a graded (70–100%) series of ethyl alcohols for 10 min each. Then, the sections were blocked and embedded in Epoxy Resin KIT (AGAR 100^®; Agar Scientific Ltd, Stansted, UK. LXB 2188. Ultramicrotome NOVA, LKB Instruments, Bromma, Sweden). The semithin sections of the tissues were cut at a thickness of 0.5–1 µm to visualize after staining with toluidine blue. Ultrathin sections were obtained with a gold impediment color using (50–100 nm) an ultra microtome (LXB 2188, NOVA, LKB, Bromma, Sweden) and monitored using a EM (JEM-100SX, Jeol, Tokyo, Japan) operated at an accelerating voltage of 20–80 kV after staining with uranyl acetate and lead citrate. Electron micrographs of this specimen were taken at a magnification of 3000× and 10,000× to examine the ultrastructural changes in hepatocytes. Electron micrographs were obtained using an Electron Microscope Camera (EM 9 Carl Zeiss, Germany).

Light microscopy

Different parts of the liver were excised after decapitation. One part was fixed in 10% formaline solution for 24 h. Another part was fixed for EM observation. Tissue pieces were dehydrated in a series of alcohol, cleared in xylene and embedded in liquid paraffin (56–58°C, Merck KGaA, Darmstadt, Germany). The specimens were sectioned at 3–6 μm using a rotary microtome (Leica RM2255 Rotary Microtome, Leica Biosystems, Nussloch, Germany) and stained with Mallory’s triple stain modified by Crossman. Then the slides were evaluated and graded for the histopathological changes under light microscope by two histologists and one pathologist blinded to group allocations.

Immunohistochemical study

Histological sections (3–6 µm) were deparaffinized in xylene for 20 min. The slides were progressively dehydrated in increasing concentration of graded ethanol from 70 to 99% and were air-dried. The sections were dipped in both 3% hydrogen peroxide for 20 min and in distilled water for a period of 10 min at room temperature to block endogenous peroxidase activity. Phosphate-buffered solution (PBS, pH = 7.4) was used for all subsequent washes in two 5 min periods. The slides were waited to heat in the microwave (400–800 W) for 5–10 min in citrate buffer (pH = 6.0) for antigen retrieval. After nonspecific binding was blocked with blocking reagent for 5 min, primary antibodies as CN (Purified Mouse Anti-CN (Clone:29/CN) BD Biosciences, California, USA) and a biotinylated secondary antibody (Universal LSAB Kit-K0690, DAKO Denmark A/S, Glostrup, Denmark) were applied at 1:250 dilutions for CN at room temperature for 75 min. A universal kit was used with the rabbit/mouse streptavidin biotin technique. Visualization of the bound primary antibodies was performed with 3,3′-diaminobenzidine tetrahydrochloride (Sigma-D5905, Missouri, USA) as a chromogen and counterstained with Harris hematoxylin for nuclei stain. PBS without the primary antibody was used for negative control and a separate positive control slide of testis, which was shown previously to be strongly positive, was used for each antibody. Photographs of antibody binding were examined under a light microscope (Olympus BX51, Olympus Corporation, Tokyo, Japan) and a section photographs were taken using the digital camera (Olympus DP72, Tokyo, Japan).

Three histologists who were blinded to the treatments graded immunoreactivity and pathologic changes according to immunohistochemistry and histopathological staining of each specimen. Score grades: (1) 25% weak, (2) 50% moderate and (3) 75% strong.

Blood samples were withdrawn from the tail vein to measure the levels of glucose, Ca, Mg, K, aspartate transaminase (AST) and alanine transaminase (ALT). Levels were determined using a standard autoanalyzer (Architect c16000 Autoanalyzer, Abbott Diagnostics, Worcester, Massachusetts, USA).

Statistical analysis

Differences between means of blood biochemistry analysis of all the groups were estimated using a one-way analysis of variance followed by least significant difference test (post hoc) using the SPSS software (SPSS 18 for Windows, IBM, Chicago, Illinois, USA). The p < 0.005 were considered statistically significant. Sample size was obtained from a similar study reported from the literature and from a pilot study.^13,22.

Immunopositivity and pathological data were analyzed with the SPSS. The data did not demonstrate normal distribution with both Kolmogorov–Smirnov and Shapiro–Wilk tests. These groups were evaluated separately by Mann–Whitney U test (post hoc with Bonferroni’s correction) after all results were analyzed using Kruskal–Wallis test. The p value is obtained by dividing 0.05 by 10 for the number of comparisons. The p < 0.005 was considered statistically significant.

Results

EM histopathological examination

In EM investigation, hepatocytes in control group revealed normal nuclei membrane, rough endoplasmic reticulum and mitochondria (Figure 1(a)). But in 40 mg kg⁻¹ group, there were destruction in rough endoplasmic reticulum and undulated nuclear membrane (Figure 1(b)). In 60 mg kg⁻¹ group, sinusoidal narrowing, hyperchromatic endothelial cell nuclei, thickening of endothelial basal lamina as well as endothelial disconnection in the sinusoidal lumen were observed (Figure 1(c)). In 80 mg kg⁻¹ group, destructed rough endoplasmic reticulum, degenerated and vacuolated mitochondria were observed in hepatocyte cytoplasm. Moreover, abnormal material accumulation was seen in the intermitochondrial area (Figure 1(d)). Also in the sections obtained from 100 mg kg⁻¹ group, we observed degenerated mitochondria and intracytoplasmic vacuolization in the hepatocyte (Figure 1(e)), and there was a hypertrophied Ito cell in the hepatic sinusoidal area, in which vacuolated cytoplasm and collagen accumulation were seen in perisinusoidal area (Figure 1(f)).

Figure 1.

Electron microscopic examination to the ultrastructural changes of hepatocytes (A); control groups, n: nucleus of hepatocyte, (B); m: mitochondrion, n: nucleus of hepatocyte, m:mitochondrion, arrows: membrane undulation, (C); sinusoid of hepatocyte, e: endothelia, (D); arrow:mitochondrial vacuolization and destructed rough endoplasmic reticulum, (E); arrow: mitochondrial vacuolization, asterisks; vacuolization in the hepatocyte cytoplasm, and (F); s: sinusoidal lumen, it: ito cell, asterisks: vacuolization in the ito cells (perisinusoidal cells) cytoplasm, and arrows: collagen synthesis. 3000X. and 10000X Bar:0,5-µm.

Light microscopic histopathological and immunohistochemistry examination results

In light microscopy, hepatocytes in control group showed normal morphology. There was significantly less vacuolization in control, 40 and 100 mg kg⁻¹ groups when compared with groups 60 and 80 mg kg⁻¹ (p < 0.005). Groups 60, 80 and 100 mg kg⁻¹ had significantly higher cell degeneration and sinusoidal dilatation compared with control group (p < 0.005). Furthermore, hepatocyte necrosis seen in groups 60, 80 and 100 mg kg⁻¹ was significantly higher than control and 40 mg kg⁻¹ groups (p < 0.005; Table 1).

Table 1.

Blinded grading for the histopathological scoring of all the groups and the data were expressed as median ± SD (M ± SD).

n: 6	Vacuolization		Cell degeneration		Sinusoidal dilatation		Necrosis		Immunopositivity
n: 6	Score	M ± SD	Score	M ± SD	Score	M ± SD	Score	M ± SD	Score	M ± SD
Control group	+	1.00 ± 0.41	+	1.00 ± 0.00	+	1.00 ± 0.41	−	0.00 ± 0.41	+++	3.00 ± 0.52^a
Group 40 mg kg⁻¹	+	1.00 ± 0.41	+	1.00 ± 0.52	++	2.00 ± 0.41	−	0.00 ± 0.52	++	2.00 ± 0.41
Group 60 mg kg⁻¹	+++	3.00 ± 0.41^b	++	2.00 ± 0.41^c	+++	3.00 ± 0.41^d	++	2.00 ± 0.41^e	++	2.00 ± 0.52
Group 80 mg kg⁻¹	+++	3.00 ± 0.52^b	++	2.00 ± 0.00^c	+++	3.00 ± 0.41^d	++	2.00 ± 0.41^e	+	1.00 ± 0.41^a
Group 100 mg kg⁻¹	+	1.00 ± 0.00	+++	3.00 ± 0.41^c	+++	2.50 ± 0.90^d	+++	3.00 ± 0.52^e	+	1.00 ± 0.63^a

^a p < 0.005 to other group with control group for immunopositivity.

^b p < 0.05 to other group with control group for vacuolization.

^c p < 0.05 to other group with control group for cell degeneration.

^d p < 0.05 to other group with control group for sinusoidal dilatation.

^e p < 0.05 to other group with control group for necrosis.

The highest immunopositivity score was observed in the control group (+++). There was a statistically significant difference between immunopositivity of groups 80 and 100 mg kg⁻¹ when compared with control group (p < 0.005; Figures 2 and 3; Table 1).

Figure 2.

Light microscopic histopathological examination. Control group (1 and 1a); H: hepatocyte, S: Sinusoid, CV: central vein, Group 40 mg kg^-1 (2 and 2a); H:hepatocyte, arrowhead: sinusoidal dilatation, CV: central vein, Group 60 mg kg^-1 (3 and 3a); E: edema,V: vacolisation, arrowhead: sinusoidal dilatation, thick arrow: cell degeneration, thin arrow; Group 80 mg kg^-1 (4 and 4a), V: vacolisation, arrowhead: sinusoidal dilatation, thick arrow: cell degeneration, Group 100 mg kg^-1 (5 and 5a), arrowhead: sinusoidal dilatation, thick arrow: cell degeneration. Mallory's triple stainand toluidine blue stain, 40X, bar:20 µm.

Figure 3.

Light microscopic histopathological and immunohistochemistry examination. Control group (1), Group 40 mg kg^-1 (2), Group 60 mg kg^-1 (3), Group 80 mg kg^-1 (4) and Group 100 mg kg^-1 (5); asterisk: calcineurin-positive cells, V: vacolisation, immunoperoxidase staining (Anti-Calcineurin), 40X, bar:20 µm.

Group 40 mg kg⁻¹: when compared with control group, the cell density and the structure of hepatocytes were similar. But in comparison with the control group, the width of the sinusoids was slightly dilated. This groups was less immunopositive than the control group (++; Figures 2 and 3; Table 1).

Group 60 mg kg⁻¹: while moderate cell degeneration and necrotic areas in some places were observed in this group, marked vacuolization and sinusoidal dilatation were detected. Similar intensity of immunopositivity was observed when compared with group 40 mg kg⁻¹ (++; Figures 2 and 3; Table 1).

Group 80 mg kg⁻¹: the cell degeneration, necrosis, vacuolization and sinusoidal dilatation were similar to the group 60 mg kg⁻¹. The immunopositivity of group 80 mg kg⁻¹ was less than the control group and groups 40 and 60 mg kg⁻¹ (Figures 2 and 3; Table 1).

Group 100 mg kg⁻¹: the most intensive cell degeneration, sinusoidal dilatation and necrosis were observed in this group. The density of the hepatocytes vacuolation was similar to the control group and group 40 mg kg⁻¹. The immunopositivity was similar to the group 60 mg kg⁻¹ (Figures 2 and 3; Table 1).

Edema and dilatation of sinusoids around the hepatic central vein were identified in the groups 60, 80 and 100 mg kg⁻¹. In addition, hepatocytes were swollen and cytoplasm appeared to be pale. These changes were not observed in control and group I. In the microscopic analysis of the groups 40, 60, 80 and 100 mg kg⁻¹, cellular degeneration with acidophil bodies similar to apoptotic cells around the central vein was determined (Figure 2). Ketamine had relatively little effect on vascular endothelium of all the groups; it was limited to mild/moderate endothelial swelling.

Biochemical analysis results

Administration of different high doses of ketamine increased serum enzyme levels of ALT and AST. There was statistically significant difference between both AST and ALT levels of all the groups with control group (p < 0.05). An increase in the blood calcium in the treated groups was observed, whereas a slight to significant decrease in Mg and K were found in the same groups, respectively (Table 2).

Table 2.

Results of blood biochemistry analysis.^a

n: 6	Ca (mg dL⁻¹)	Mg (mg dL⁻¹)	K (mmol L⁻¹)	Glucose (mg dL⁻¹)	AST (U L⁻¹)	ALT (U L⁻¹)
Control group	6.22 ± 0.31^b	2.49 ± 0.02^c	6.13 ± 0.27^d	78.67 ± 9.99^e	26 ± 1.98^f	64.33 ± 5.46^g
Group 40 mg kg⁻¹	5.95 ± 0.22^b	2.32 ± 0.04^c	4.8 ± 0.25^d	100.83 ± 9.80	62.83 ± 2.27^f	98.83 ± 3.62^g
Group 60 mg kg⁻¹	7.25 ± 0.16^b	2.3 ± 0.01^c	3.99 ± 0.09^d	116.33 ± 9.57^e	80 ± 2.87^f	124.5 ± 2.56^g
Group 80 mg kg⁻¹	7.88 ± 0.29^b	2.24 ± 0.02^c	3.67 ± 0.10^d	128.16 ± 7.09^e	192 ± 15.70^f	203.33 ± 5.52^g
Group 100 mg kg⁻¹	10 ± 0.55^b	2.01 ± 0.04^c	3.52 ± 0.11^d	135 ± 4.05^e	217.67 ± 6.58^f	213.67 ± 5.43^g

IV: intravenous; ALT: alanine transaminase; AST: aspartate transaminase; Ca: calcium; Mg: magnesium; K: potassium.

^aThe data were expressed as means ± SEM.

^b p < 0.05 to all groups with group IV.

^c p < 0.05 to other group with control group and group IV.

^d p < 0.05 to other group with control group and group I.

^e p < 0.05 to other group with control group.

^f p < 0.05 to all groups with control group.

^g p < 0.05 to all groups with control group.

Blood glucose levels of groups 60, 80 and 100 mg kg⁻¹ were significantly higher than the control group (p < 0.05). When compared with the control group, calcium levels of the all other groups were significantly higher (Table 2; p < 0.05). Furthermore, calcium levels of group 100 mg kg⁻¹ was significantly higher than those of groups 40, 60 and 80 mg kg⁻¹ (p < 0.05). Mg levels of the control group was significantly higher than those of other groups (Table 2). Furthermore, Mg levels in group 100 mg kg⁻¹was also significantly lower than those of all other groups (p < 0.05). K levels were lower in groups 60, 80 and 100 mg kg⁻¹ when compared with control group and group 40 mg kg⁻¹ (p < 0.05).

Discussion

The results of the present study demonstrated that ketamine causes significant hepatic damage in rats. Histopathological changes as vacuolization and cell degenerations in low-doses of ketamine (group 40 mg kg⁻¹) were similar to the control group. But immunopositivity was lower in ketamine groups than the control group. Our study revealed that long-term use of ketamine could also cause pathological alterations visible with light microscopy. These results were confirmed with EM as well.

Liver toxicity of ketamine was reported in some animal studies²³; however, hepatotoxicity of ketamine was considered as a rare side effect in human clinical trials.²⁴ In a postmarketing study, it was reported that 721 people had side effects due to ketamine. Among them, one person developed (0.14%) liver disorder, another pancreatitis.^22,25 Furthermore, hepatotoxicity of long-term ketamine abuse causes elevation in liver enzymes, which has been shown in some recent studies. Therefore, provided information by ketamine producers rightly warns against its use in liver and kidney disorders.^26–29 According to Wai et al., ketamine use in rats caused significant liver damage in the forms of fatty degeneration and fibrosis.³⁰ Prolong administration of ketamine induces hepatotoxicity in patients with chronic pain.³¹ Supporting this, we have also demonstrated significant dose-dependent hepatotoxicity with ketamine.

Ketamine induces apoptotic cell deaths associated with mitochondrial degeneration in hepatic cells.³² CN a calcium-dependent protein phosphatase that plays an important role in apoptotic cell deaths was activated by calcium.³³ In the present study, significant mitochondrial degenerations and vacuolization in EM and apoptotic cells with acidophil bodies in light microscopic examination of hepatocytes in groups 80 and 100 mg kg⁻¹ were determined. Moreover, there were decreases in immunoreactivity of CN-positive cells by high-dose ketamine. Studies have demonstrated that ketamine also has significant effects on vascular endothelial cells in liver.¹² In our study, significant sinusoidal dilatation was observed, this may affect the biliary tract and pancreas especially with chronic use. In addition, a previous study has shown ketamine to cause fusiform dilatation of the hepatic and bile ducts.²⁶ This effect on the biliary tract has been usually ignored by researchers.

Effects of ketamine on plasma K levels were evaluated during anesthesia induction, which revealed that it remained below the baseline values.³⁴ A total of 714 people have been reported to have between mild and more serious side effects with ketamine. Among them, there were only two patients (0.28%) with reduction in K or hypokalemia.³⁵ Supporting these in our study we found dose-dependent decrease in serum K levels. This may have important clinical implication in patients with high K levels requiring anesthesia induction or in patients with low K levels.

Studies have demonstrated that ketamine causes an increase in extracellular calcium levels. It also causes significant decrease in the immunoreactivity of the CN.¹⁸ In our study, we saw different degrees of decrease in the immunoreactivity of the CN in ketamine groups. Ketamine also affects liver functions tests and blood glucose levels.³⁶ Current study revealed that the glucose and calcium levels showed a slight increase compared with the control group. In addition, there is a relationship between hepatotoxity and the histopathological changes with the increase in calcium levels. These histopathological changes are not clinically significant.

We used four different doses (40, 60, 80 and 100 mg kg⁻¹) of ketamine to cover almost all the possible doses used in rats. The sedation dose of ketamine for rats range between 75 and 100 mg kg⁻¹ intraperitoneal (ip).³⁷ The ip lethal dosage (LD₅₀) values of mature rats and mice are approximately 100 times the average human intravenous (IV) dose. Thus, the dose we used is acceptable for rats and similar doses have been used in previous studies. Human doses are relatively low compared with rats but the average human intramuscular dose is approximately 20 times the IV dose, which is relatively high as well.³⁷

There are number of limitations in current study. However, the main limitation of this study is the requirement of relatively high dose of sedatives in rats. This dose is much higher than the sedative dose required in humans, mainly due to high metabolic rate of rats. Therefore, doses of 40–100 mg kg⁻¹ were administered and investigated in this study. Human studies with clinically relevant doses are required to determine the effect of long-term ketamine in human liver functions and structure.

In current study, ketamine was given by ip injection, this route is not used in humans. However, IV injection in rats may interfere with the nutrition of the animals and is more difficult to apply than ip injection, which is why the ip route is more often chosen. Furthermore, ip ketamine injection seems to cause less damage to rats when compared to IV injection.³⁸ Another and very important limitation of our study is that it does not provide any insight to clinical impact of this changes. However, current study would lay the basis of future clinical studies.

Conclusion

As a result, long-term and high-dose ketamine usage has histopathological effects such as mitochondrial degeneration, intracytoplasmic vacuolization and apoptosis on liver histology in rats. It is not yet known, if these pathological changes are reversible or permanent. These results obtained from animal studies grant human investigations to determine whether similar changes are observed in patients with chronic pain given in ketamine or in recreational users.

Footnotes

Funding

The all costs were funded by the authors.

Conflict of interest

The authors declared no conflicts of interest.

References

Patterson

Hoflund

Espey

Sharar

. Pain management. Burns 2004; 30: A10–A15.

Trupkovic

Kinn

Kleinschmidt

. Analgesia and sedation in the intensive care of burn patients: results of a European survey. J Intensive Care Med 2011; 26: 397–407.

Dahan

Olofsen

Sigtermans

Noppers

Niesters

Aarts

Population pharmacokinetic–pharmacodynamic modeling of ketamine-induced pain relief of chronic pain. Eur J Pain 2011; 15: 258–267.

Craven

. Ketamine. Anaesthesia 2007; 62: 48–53.

Burmeister-Rother

Streatfeild

Yoo

. Convulsions following ketamine and atropine. Anaesthesia 1993; 48: 82.

Persson

. Wherefore ketamine? Curr Opin Anaesthesiol 2010; 23: 455–460.

White

Schüttler

Shafer

Stanski

Horai

Trevor

. Comparative pharmacology of the ketamine isomers. Br J Anaesth 1985; 57: 197–203.

Murdoch

Crooks

Miller

. Effect of the addition of ketamine to morphine in patient-controlled analgesia. Anaesthesia 2002; 57: 484–488.

Haas

Harper

. Ketamine: a review of its pharmacologic properties and use in ambulatory anesthesia. Anesth Prog 1992; 39: 61–68.

10.

Kim

Lee

Choi

Lim

Chung

. Analysis of ketamine and norketamine in urine by automatic solid-phase extraction (SPE) and positive ion chemical ionization–gas chromatography–mass spectrometry (PCI-GC-MS). Forensic Sci Int 2008; 174: 197–202.

11.

Navarro

Senior

. Drug-related hepatotoxicity. N Engl J Med 2006; 354: 731–739.

12.

Rofael

. Effect of ketamine pretreatment on cocaine-mediated hepatotoxicity in rats. Toxicol Lett 2004; 152: 213–222.

13.

Saranteas

Zotos

Lolis

Stranomiti

Mourouzis

Chantzi

Mechanisms of ketamine action on lipid metabolism in rats. Eur J Anaesthesiol 2005; 22: 222–226.

14.

Krishnamoorthy

Freeman

Austin

. Cholestasis and biliary dilatation associated with chronic ketamine abuse: a case series. Singapore Med J 2011; 52: e52–e55.

15.

Navarro

Senior

. Drug-related hepatotoxicity. N Engl J Med 2006; 354: 731–739.

16.

Kane

Young

Schanne

Farber

. Calcium dependence of phalloidin-induced liver cell death. Proc Natl Acad Sci USA 1980; 77: 1177–1180.

17.

Chang

Chen

. Cytoskeleton interruption in human hepatoma HepG2 cells induced by ketamine occurs possibly through suppression of calcium mobilization and mitochondrial function. Drug Metab Dispos 2009; 37: 24–31.

18.

Chen

RM.

, Mechanisms of ketamine-involved regulation of cytochrome P450 gene expression. Expert Opin Drug Metab Toxicol 2010; 6: 273–281.

19.

Macian

. NFAT proteins: key regulators of T-cell development and function. Nat Rev Immunol 2005; 5: 472–484.

20.

Lipskaia

Lompré

. Alteration in temporal kinetics of Ca²⁺ signaling and control of growth and proliferation. Biol Cell 2004; 96: 55–68.

21.

Zhao

Tozawa

Iseki

Mukai

Iwata

. Calcineurin activation protects T cells from glucocorticoid-induced apoptosis. J Immunol 1995; 154: 6346–6354.

22.

Could ketamine HCl cause pancreatitis? http://www.ehealthme.com/ds/ketamine+hcl/pancreatitis (accessed 04 April 2012).

23.

Chan

Sun

Ueng

. Induction of rat hepatic cytochrome P-450 by ketamine and its toxicological implications. J Toxicol Environ Health A 2005; 68: 1581–1597.

24.

Noppers

Niesters

Aarts

Bauer

Drewes

Dahan

Drug-induced liver injury following a repeated course of ketamine treatment for chronic pain in CRPS type 1 patients: a report of 3 cases. Pain 2011; 152: 2173–2178. Pain 2012; 153: 502.

25.

Could ketamine HCl cause liver disorder? http://www.ehealthme.com/ds/ketamine+hcl/liver+disorder (accessed 04 April 2012).

26.

Wong

Lee

Wong

Cheung

Lai

. Dilated common bile ducts mimicking choledochal cysts in ketamine abusers. Hong Kong Med J 2009; 15: 53–56.

27.

Pai

Heining

Ketamine. Continuing education in anaesthesia. Crit Care Pain 2007; 7: 59–53.

28.

DeClue

Cohn

Lechner

Bryan

Dodam

. Effects of subanesthetic doses of ketamine on hemodynamic and immunologic variables in dogs with experimentally induced endotoxemia. Am J Vet Res 2008; 69: 228–232.

29.

Braun

Gaza

Werdehausen

Hermanns

Bauer

Durieux

Ketamine induces apoptosis via the mitochondrial pathway in human lymphocytes and neuronal cells. Br J Anaesth 2010; 105: 347–354.

30.

Wai

Chan

Zhang

Yew

. Long-term ketamine and ketamine plus alcohol treatments produced damages in liver and kidney. Hum Exp Toxicol 2012; 31: 877–886.

31.

Noppers

Niesters

Aarts

Bauer

Drewes

Dahan

Drug-induced liver injury following a repeated course of ketamine treatment for chronic pain in CRPS type 1 patients: a report of 3 cases. Pain 2011; 152(9): 2173–2178.

32.

Shibasaki

McKeon

. Calcineurin functions in Ca(2+)-activated cell death in mammalian cells. J Cell Biol 1995; 131: 735–743.

33.

Gal

Malit

. The influence of ketamine induction on potassium changes and fasciculations following suxamethonium. Br J Anaesth 1972; 44: 1077–1080.

34.

Gal

Malit

LA.

The influence of ketamine induction on potassium changes and fasciculations following suxamethonium. Br J Anaesth. 1972; 44(10): 1077–80.

35.

Sharma

Sen

. Effect of ketamine on blood sugar and liver functions. Indian J Anaesth 1985; 33: 29–30.

36.

Saha

Xia

Grondin

Engle

Jakubowski

JA.

Acute hyperglycemia induced by ketamine/xylazine anesthesia in rats: mechanisms and implications for preclinical models. Exp Biol Med (Maywood). 2005; 230(10): 777–84.

37.

Sinner

Graf

BM.

Ketamine. Handbook of experimental pharmacology. Handb Exp Pharmacol. 2008; 182: 313–33.

38.

Smiler

Stein

Hrapkiewicz

Hiben

. Tissue response to intramuscular and intraperitoneal injections of ketamine and xylazine in rats. Lab Anim Sci 1990; 40: 60–64.

Hepatic effects of ketamine administration for 2 weeks in rats

Abstract

Keywords

Introduction

Materials and methods

Study design

Tissue processing

Electron microscopy

Light microscopy

Immunohistochemical study

Statistical analysis

Results

EM histopathological examination

Light microscopic histopathological and immunohistochemistry examination results

Biochemical analysis results

Discussion

Conclusion

Footnotes

Funding

Conflict of interest

References