Changes Of Nitric Oxide Syathase Gene Expression After Intracerebral Hemorrhage In Rat

PURPOSES :To study the expressions of neuronal NOS,inducible NOS and endothelial NOS after intracerebral hemorrhage in rat, so as to discuss the relationgship among three NOS and secondary cerebral ischemia injury.METHODS: 72 rats were divided into normal group, control group and study group, which included subgroups as 6h, 24h, 48h and 72h respectively. The rat cerebral hemorrhage model was setup by injection of heparin and collagenase â…¦ in fixed locations of cerebrum. nNOS,eNOS and iNOS mRNA expressions in cerebral tissues after hemorrhage were detected by RT-PCR. Pathologic alteration was found under optic microscope.RESULTS:The doses of nNOS mRNA increased rapidly on the side of hemorrhage in 6 hours after occurrence ( P<0.01 ) and gradually dropped to a control level after 72 hours of hemorrhage occurrence. No significant difference was found between the normal group and control group.The doses of eNOS mRNA increased rapidly on the side of hemorrhage in 6 hours after occurrence ( P<0.01 ) and gradually dropped to a control level after 48 hours of hemorrhage occurrence. No significant difference was found between the normal group and control group. No iNOS mRNA expression was detected in 6 hours after hemorrhage occurrence. The iNOS mRNA expression was detected in 24 hours, reached its peak in 48 hours and slightly declined in 72 hours which was still significantly higher than the 24-hour group (P < 0.05).Pathology: pathologic alteration such as dilation and hyperaemia of blood vessels, neuron karyopyknosis and acidophilication can occour in 6 hours after hemorrhage, significant degeneration or necrosis were discovered in 48 hours after hemorrhage, and in 72 hours colloid cell hyperplasia was detected increasedly. No such pathologic alteration was discovered in the normal group and control group. CONCLUSIONS:There are nNOS and eNOS gene expression in normal cerebral tissue, while no iNOS gene expresses in normal cerebral tissue. eNOS and nNOS gene expression are significantly elevated shortly after hemorrhage (6h)and drop to normal level at later stage(48h~72h). The iNOS mRNA expression was detected in 24 hours, reached its peak in 48 hours and slightly declined in 72 hours. Pathologic alteration such as dilation and hyperaemia of blood vessels, neuron karyopyknosis and acidophilication can occour in 6 hours after hemorrhage, significant degeneration or necrosis were discovered in 48 hours after hemorrhage, and in 72 hours colloid cell hyperplasia was detected increasedly.eNOS,nNOS maybe related to the tissue damage in the early phase following cerebral hemorrhage. And iNOS maybe related to the tissue damage in the later phase following cerebral hemorrhage.