Apoptosis of neurons following sciatic nerve injury: A preliminary observation in rats

Objective To observe apoptosis of the motor neurons in the spinal cord and the sensory neurons in dorsal root ganglia after peripheral nerve injury in adult rats.Methods Twenty one male Sprague Dawely rats were randomly divided into two groups. In group A, the sciatic nerve was transected and ligated. In group B, sciatic nerve crushed model was set up. The rats were sacrificed in 7, 14, and 28 days postoperatively and transcardially perfused with 4 % paraformaldehyde. The L 4 ～ L 6 spinal cord segments and L 5 dorsal root ganglia (DRG) were harvested. TUNEL technique was used for detection of the apoptotic neurons.Results Apoptotic neurons were found both in group A and group B. The number of apoptotic neurons at postoperative day 14 and day 28 in the sciatic nerve transection group was larger than that in the sciatic nerve crush group. The difference was of statistic significance ( P 0.05). The difference in the number of apoptotic neurons between the two groups was not significant at day 7 ( P 0.05).Conclusions Apoptosis of neurons may be the primary process of neuronal death following peripheral nerve injury. The target derived neurotrophic factors may play a role in protection of the neurons.