Expression of heat shock proteins 70 in spinal cord and dorsal root ganglia after neurotomy of rat sciatic nerve and the effect of extract of ginkgo biloba

Objective To study the expression of heat shock protein 70 (HSP 70) in spinal cord and dorsal root ganglia after peripheral nerve injury and the influence of Ginkgo biloba extract EGb 761 on HSP 70 expression, and investigate the mechanism of the protective effect of EGb 761 after peripheral nerve injury in rats. Methods One hundred and forty-four male adult SD mrs were randomly divided into three groups, sham operation group ( n= 48), sciatic nerve transection group ( n = 48) and sciatic nerve transection and EGb 761 hours, 12 hours, 1 day, 2 days, 4 days, 7 days, 14 days and 28 days postoperatively, spinal cord of L4-L6 were harvested. Immunohistochemistry analysis was done to measure the expression of HSP 70 in anterior horns of Lt-L6 spinal cord and dorsal root ganglia. Results In normal rats' spinal cord anterior horn and dorsal root ganglia, HSP 70 was expressed. After rat sciatic nerve transection, the expression of HSP 70 increased quickly.This elevated expression lasted for a period of time, and then returned to the normal level. After being intervened by EGb 761, HSP 70 expression during the early postoperative period was lower compared with the group not being intervened. At the later period, the expression increased and lasted for a longer time. Conclusion Ginkgo biloba extract( EGb 761 ) can enhance the expression of HSP 70 after peripheral nerve injury. This could be the mechanism of the neuroprotective and neurotrophic effect of Ginkgo biloha extract. Key words: Nerve regeneration;  Spinal cord;  Ganglia, spinal;  Heat shock proteins;  Ginkgohiloha extract EGb 761