Abstract
Purpose: The pre and post-treatment effects of L-carnitine on apoptotic cell death due to hypoxia-ischemia in various regions of the brains of seven-day-old rats were investigated.
Methods: L-carnitine (group 1; n=8) or saline (group 2; n=8) was administered intraperitoneally to seven-day-old rats before hypoxia-ischemia. In addition, 16 seven-day-old rats were given L-carnitine (group 3; n=8) or saline (group 4; n=8) after hypoxic ischemic insult. Apoptotic cell death was investigated by terminal dUDP-biotin nick end-labeling (TUNEL) in all subjects following three days of recovery. In the evaluation of TUNEL- positive cells, firstly the areas (in square millimeters) of the hippocampus, striatum and cortex in the right and left hemispheres were measured by IMAGE analysis. Then the numerical density was calculated as the number of cells per square millimeter by counting all TUNEL- positive cells. Afterwards, the ratios of right side numerical density to the sum of right and left sides' numerical densities (right apoptosis index) were calculated for every brain region in rats receiving L-carnitine and they were compared with the vehicle groups.
Results: The right apoptosis indexes of the hippocampus (37.4 ± 18.8; mean ± SD) and striatum (39.2 ± 15.2) in rat pups pre-treated with L-carnitine were significantly lower than those in the vehicles (59.8 ± 17.9 vs. 60.4 ± 19.6 respectively) (p< 0.05), whereas they were not changed by L-carnitine pre-treatment in the cortex. Additionally, L-carnitine post-treatment had no effect on right apoptosis indexes in any of the three brain regions.
Conclusions: It is concluded that pre-treatment with L-carnitine might play a role in reducing apoptotic cell death due to neonatal hypoxic ischemic brain injury. Our results suggested that L-carnitine was useful in perinatal asphyxia for preventing hypoxic ischemic brain injury.
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