Effects of extract of Ginkgo biloba on apoptosis of neurocytes and expression of inducible nitricoxide synthuse after spinal cord injury in rats

Abstract

Objective To investigate the effect of extract of Ginkgo biloba (Egb) on apoptosis of nerve cells and its mechanism after spinal cord injury (SCI) in rats. Methods Forty eight adult SD rats weighing 200-230 g were divided equally and randomly into Egb group and normal saline (NS) group. After hemisectian of spinal cord at T9 vertebrae level, rats in Egb group were lavaged with 2 ml EGB (20 mg) daily and those in NS group with 2 ml NS daily. Tissue sections were collected and stained with Nissl's staining, myelin sheath staining, and inducible nitric oxide synthase (iNOS) immunohisto-chemistry as well as terminal deoxynueleotidyl transferase-mediated dUTP nick end lebeling (TUNEL) at days 1,7, 14 and 21 respectively to evaluate the injured spinal cord tissues after six rats from each group were sacrificed Results Nissl's staining manifested less swelling of the nerve cells near the injury epi-center ( rostral and caudal ), smaller cavity and demyelinated area and higher ratio of bilateral anterior horn neurons of transection side to normal side in Egb group, compared with NS group ( P <0.05). Ap-optotie index (AI) and expression of iNOS in NS group were higher than those in Egb group ( P <0.01 or P <0. 05). Furthermore, the rate of iNOS-positive cells was positively correlated with the AI (r = 0.729, P<0.01) after SCI. Conclusion Egb can prevent nerve cells from apoptosis after SCI in rats, as may be related with inhibition of expression of iNOS. Key words: Ginkgo biloba; Spinal cord injuries; Nitric oxide synthase; Neurons; Neu-roglia; Apoptosis