Effects of electroacupuncture on functional indices and pS6 expression following acute sciatic nerve crush injury in rats

Abstract

Objective:

The aim of this study was to investigate the effect of electroacupuncture (EA) on recovery from acute sciatic nerve crush injury and the expression of pS6 in rats.

Methods:

A total of 108 adult male Sprague–Dawley rats were randomly divided into control, model, EA and EA+rapamycin (EA+Rapa) groups. 28 rats were allocated to undergo measurement of sciatic functional index (SFI); one rat in the EA+Rapa group was unsuccessfully modelled and excluded because of an anaesthetic problem. The remaining 80 rats were allocated to undergo Western blot detection of S6 ribosomal protein (pS6, ser240/244). The model was created by mechanical clamping of the sciatic nerve stem. EA stimulation at GB30 and ST36 for 15 min separately was applied once daily for rats in the EA and EA+Rapa groups. For rats in the EA+Rapa group, rapamycin, a mammalian target of rapamycin (mTor) pathway inhibitor, was injected intramuscularly (1 mg/kg/day) near the site of crush injury in the sciatic nerve and an equivalent amount of dimethyl sulfoxide was injected in the other three groups every other day. After treatment for 7, 14, 28 and 42 days post-operation, the SFI of 27 rats was obtained to evaluate recovery of motor function and five rats from each group per stage were used for Western blot detection of pS6.

Results:

The SFI values showed that EA could significantly promote recovery of the injured sciatic nerve but rapamycin hindered the therapeutic effect of EA. Moreover, immunoblotting indicated that EA improved the expression of pS6 in the area of the sciatic nerve crush injury and local injection of rapamycin near the injured sciatic nerve decreased its expression. The pS6 level correlated with the extent of recovery of the injury.

Conclusions:

This study indicated that EA may activate the mTOR signalling pathway to enhance expression of pS6 and facilitate recovery following sciatic nerve crush injury.

Keywords

electroacupuncture sciatic nerve crush injury mammalian target of rapamycin S6 ribosomal protein Western blotting

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References

Lao

, et al. [Efficacy observation on traumatic nerve injury treated with different acupuncture therapies]. Zhongguo Zhen Jiu 2013; 33: 993–995.

Gao

. 168 cases of acupuncturing huantiao and weizhong on sciatica. Hebei J Traditional Chinese Medicine 2002; 24: 41.

Zhao

. Neural mechanism underlying acupuncture analgesia. Prog Neurobiol 2008; 85: 355–375.

Hseuh

O’Connor

. Acupuncture: a comprehensive text. Chicago: Eastland Press, 1981.

Chang

Namgung

. Induction of regenerative responses of injured sciatic nerve by pharmacopuncture therapy in rats. J Acupunct Meridian Stud 2013; 6: 89–97.

Zeng

Nie

Zhang

, et al. Morphine acts via mu-opioid receptors to enhance spinal regeneration and synaptic reconstruction of primary afferent fibers injured by sciatic nerve crush. Brain Res 2007; 1130: 108–113.

Hoang

Sar

Valmier

, et al. Electro-acupuncture on functional peripheral nerve regeneration in mice: a behavioural study. BMC Complement Altern Med 2012; 12: 141.

Sun

Cui

Luo

, et al. [Effect of electroacupuncture on the expression of spinal glial fibrillary acidic protein, tumor necrosis factor-alpha and interleukin-1beta in chronic neuropathic pain rats]. Zhen Ci Yan Jiu 2010; 35: 12–16.

Laplante

Sabatini

. mTOR signaling in growth control and disease. Cell 2012; 149: 274–293.

10.

Park

Liu

, et al. Promoting axon regeneration in the adult CNS by modulation of the PTEN/mTOR pathway. Science 2008; 322: 963–966.

11.

Park

Liu

, et al. PTEN/mTOR and axon regeneration. Exp Neurol 2010; 223: 45–50.

12.

Cho

Di Liberto

Carlin

, et al. Syntaxin13 expression is regulated by mammalian target of rapamycin (mTOR) in injured neurons to promote axon regeneration. J Biol Chem 2014; 289: 15820–15832.

13.

Christie

Webber

Martinez

, et al. PTEN inhibition to facilitate intrinsic regenerative outgrowth of adult peripheral axons. J Neurosci 2010; 30: 9306–9315.

14.

Lee

Luo

Yungher

, et al. Mammalian target of rapamycin’s distinct roles and effectiveness in promoting compensatory axonal sprouting in the injured CNS. J Neurosci 2014; 34: 15347–15355.

15.

Abe

Borson

Gambello

, et al. Mammalian target of rapamycin (mTOR) activation increases axonal growth capacity of injured peripheral nerves. J Biol Chem 2010; 285: 28034–28043.

16.

Sendtner

Schmalbruch

Stöckli

, et al. Ciliary neurotrophic factor prevents degeneration of motor neurons in mouse mutant progressive motor neuronopathy. Nature 1992; 358: 502–504.

17.

Pan

, et al. Investigation of electroacupuncture on NT-3 and TrkC expression in dorsal root ganglia in rats with sciatic nerve injury. Chinese J Rehab Med 2014; 29: 1109–1112.

18.

Dai

Han

, et al. Effects of deep electroacupuncture stimulation at “Huantiao” (GB 30) on expression of apoptosis-related factors in rats with acute sciatic nerve injury. Evid Based Complement Alternat Med 2015; 2015: 1–8.

19.

Hou

Yang

, et al. The method of electroacupuncture alleviating rats’ inflammatory pain on Huantiao acupoint. Medical Innovation of China 2015; 12: 22–24.

20.

Cui

Zhu

, et al. Specificity of sensory and motor neurons associated with BL40 and GB30 in the rat: a dual fluorescent labeling study. Evid Based Complement Alternat Med 2013; 2013: 1–6.

21.

Song

Wang

, et al. Electroacupuncturing at Zusanli point (ST36) attenuates pro-inflammatory cytokine release and organ dysfunction by activating cholinergic anti-inflammatory pathway in rat with endotoxin challenge. Afr J Tradit Complement Altern Med 2014; 11: 469–474.

22.

Akhlaghi

Mobarakeh

Mokhtari

, et al. The effects of altered ultrasound parameters on the recovery of sciatic nerve injury. Iran Biomed J 2012; 16: 107–112.

23.

Magnuson

Ekim

Fingar

. Regulation and function of ribosomal protein S6 kinase (S6K) within mTOR signalling networks. Biochem J 2012; 441: 1–21.

24.

Chen

Yang

. [Effect of electroacupuncture on mRNA expression of NGF and IGF-1 in injured nerve]. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 2000; 14: 328–331.

25.

Liu

Wang

. Effect of electroacupuncture on expression of NGF mRNA on restoration of injured sciatic nerves in rabbits. J Clin Electroneurophys (China) 2007; 16: 268–270.

26.

Liu

Ren

, et al. [Effect of deep electroacupuncture stimulation of “Huantiao” (GB 30) on changes of function and nerve growth factor expression of the injured sciatic nerve in rats]. Zhen Ci Yan Jiu 2014; 39: 93–99.

27.

Huang

Zou

Wang

. Effect of electroacupuncture on mRNA expression of NGF and IGF-1 in sciatic nerve of diabetic rat. Res Int Traditional Chinese and Western Med 2010; 2: 57–60.