Abstract: Objective To investigate the effect of sodium nitroprusside (SNP)on hippocampal neuronal nitricoxide synthase(nNOS) expression after focal cerebral ischemia- reperfusion in rats and the mechanism of neuroprotective effect of SNP. Method 108 male SD rats weighting 250g- 300g were randomly divided into 3 groups(n=36) . Focal ischemia- reperfusion was established by occlusion of middle cerebral artery(MCA) .Control group(C) : in which sham operation was performed;Ischemia- reperfusion group(I) : after sodium chloride (5 ul)was injected into the lateral cerebral ventricle using microsyringe,MCA was occluded for 2h;SNP group(S) : SNP(0.055 mg/kg, 5 ul)was injected into the lateral cerebral ventricle using microsyringe,then MCA was occluded for2 h. The experimental groups were further divided into 3 subgroups (n=12)according to the reperfusion time: 2h,6h and 12 h. Neurological function score were
tested before reperfusion;Pathological changes were observed by HE staining;The hippocampal tissue were obtained for detection of nNOS protein expression by immuno- histochemistry technique and nNOS mRNA expression by RT- PCR technique. Results Neuronal mortality in every subgroup of group I and S increased significantly compared with that in groupC (P<0.05) ;Compared with that in 2h (43.8±2.1), 6h(73.9±4.7)subgroup of groupI,neuronal mortality in 2h(36.5±1.2) ,6h(42.6±1.9)subgroup of group S decreased significantly (P<0.05) ;There were more nNOS mRNA expression in every subgroup of groupI and S compared with that in groupC(P<0.05),nNOS mRNA expression in 2h(0.4283±0.0004),6h(0.4827±0.0052) subgroup of group S decreased compared with that in 2h(0.4721±0.0115) ,6h (0.7442±0.0116) subgroup of groupI (P<0.05) ;The expression of nNOS protein in other subgroup of groupI and S increased except that in 6h subgroup of group S (P<0.05) ; Compared with that in 2h (0.2658±0.0005),6h (0.2840±0.0134)subgroup of groupI,the expression of nNOS protein in 2h(0.2514±0.0011),6h(0.2589±0.0040)subgroup of group S decreased(P<0.05) . Conclusion SNP could attenuate the focal cerebral ischemia/reperfusion injury and the possible mechanism may be related to the inhibition of nNOS expvession.
the inhibition of nNOS expvession.
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