EFFECTS OF
SELECTIVE NITRIC OXIDE SYNTHASE SUBTYPE INHIBITORS ON THE HYPOXIC-ISCHEMIC
CEREBRAL INJURIES IN NEWBORN RATS
Yang M1, Zhao L2
1 Beijing Children�s Hospital Affiliated to Capital University of
Medical Sciences. Beijing, China
2 The 1st affiliated Hospital of Jiangxi Medical
University, Nanchang, Jiangxi, China
Objective: To observe the effects of different NOS
inhibitors administered in the HIE model rats on the hypoxic-ischemic
cerebral injury and study the probable mechanism, providing experimental
basis for the clinical application of NO and its relative agents．
Methods: The models of HIE were established in newborn
rats. Taking SOD, MDA as the indices of the severity of cerebral injuries,
we observed the changes of NO, SOD, MDA in brain tissue after administering
selective or nonselective NOS inhibitors, and analyzed the different
correlativity between NO and SOD, MDA when the derivation and concentration
of NO were different. Pathologic changes of brain tissue were documented.
Results: The NO concentration rose after the rats
underwent HI, which had certain fluctuating patterns, accompanied with the
decrease of SOD and the increase of MDA. Both L-NAME and AG can reduce the
NO concentration, but the extent and time phase were different. L-NAME did
not have significant protective effect on HI in early stage (<8hr), but
in later stage (24hr) it did. However AG showed a good protective effect
during the whole stage. There were certain correlativity between NO and
SOD,MDA in AG group.
Conclusions: To some extent and during certain time
phase, the derivation of NO may have a closer relationship with SOD ,MDA
than the concentration. The expression of cNOS in the early stage of HI can
protect the cerebra against injuries, but the excessive expression of iNOS
may result in cerebral injuries in later stage. Selective inhibitors of
iNOS can alleviate the oxygen-derived free radical injuries of cerebra
after HI.
Key words: Nitric oxide, Enzyme inhibitor, Cerebral
anoxia, Cerebral ischemia SOD, MDA