Study On The Effect Of SeHA Anti-oxidation Injury And Its Mechanism Of Therapeutic Action To Cerebral Vasospasm

GPX react very important role in the against activities of the lipid peroxidation of damage.And the lipid peroxidation is a major chain of the cerebral vasospasm happen and develop. Due to the limitations associated with native GPX (solution instability, limited cellular accessibility, and proteolyticdigestion). Basing on the relation of framework and function of GPX, a novel selenide hyaluronic acid (SeHA) was synthesized to be functioned as a mimic of glutathione peroxidase. Basing on the framework of hyaluronic acid (HA) and method of chemical modification, the GPX activities of SeHA was determined to be 276 U/μmol, which is 278 times higher than that of Ebselen, respectively. SeHA exhibits the highest GPX activity among the reported small GPX mimics.The GPX activities of SeHA was determined to be 276 U/μmol, which is 278 times higher than that of Ebselen, respectively. Because of some advantages of SeHA (high GPX activity, good water solubility, low cost of production, stability and so on), it has great potential in antioxidant drug. We test the activity of SeHA and first to put it into act.The pathlogical damage of SAH to the cerebral vessel is a typical example the lipid peroxidation destroy the organism. Cerebral vasospasm(CVS) means a abnormal contactiong of an artery for a definite time, which is the major death cause of SAH patient. After the SAH happened, the red blood cell splits. Haemoglobin effect the muscle fiber directly, or effect the artery wall indirectly to release vasoactive substance. The free radicle and LPO have been released may attack multivalent unsaturated fatty acid, that evoke the lipid peroxidation reaction. Besides causing and aggravating cerebral vasospasm the accumulated LPO during this chain reaction can also destroy the cerebral arteries endothelial cell and smooth muscle cell. Since some scientist found Apoptosis endothelial cells in spasmus vessels of CVS death patient,the apoptosis of the vessel wall evoke a new argument. It confirmed that caspases,fas,bcl-2-bax Fam and iegs are all expressed in the apoptosis cellsobjectiveTo test the biological activity of SeHA through animal experiment .and study the effection of SeHA to nervous system overoxidation damage.ApproachTo study the activity of SeHA in vitro, antioxidant activity was studied by using three different model system: ferrous sulfate/ascorbate-induced mitochondria damage model system, H2O2 induced erythrocytes hemolysis and Hydroper-Oxidation model system and H2O2 induced C6 cells oxygenize damage model in neurospongioma. To study the activity of SeHA in vivo, the animal models of rats with Subarachnoid Hemorrhage were established by injection of twice cisternal magna: SeHA -loaded microspheres were prepared by solid-in-oil-in-water (S/O/W) technique, employing a polymer of poly (lactic acid-co-polyglycolic acid) (PLGA) as the carrier material, and sustained release in rats cisternal magna to prevent cerebral vasospasm.examine the blood flow rate and resistent index of basilar artery during every period of cerebral vasospasm by Doppler ultrasound to evaluate the curative effect of SeHA impregnated microsphere to the animal models of rats with cerebral vasospasm. To test the effection of SeHA to vasospasm and vessel wall cell apoptosis, we take some tissue of the model rat's brain, observe the anti-lipid peroxidation activity of SeHA in vivo experiment (the RT-PCR of Bcl-2,Bax, protein electrophoresis, the patho- stain of TUNEL,Bcl-2 and Bax), and study the the influence of CVS after SAH by the SeHA.ResultThe three different biotic damage system in vitro show that, SeHA can not only inhibit expanding of impaired emitochondrial membrane which is induced by Fe2+/Vc, generateing of alonaldehyde and deactivation of cytochrome-oxydase, but also prevent from the impaired red blood cell oxy-haematolysis, the haemoglobin decreaseing and red blood cell lipid peroxidation. During the neurogliocytoma C6 cell oxidative damage system, the MTT shows in the H2O2 group cell multiplication decreased,this tendency is oppsite to the density of SeHA. View the related genes(bcl-2,Bax,Caspase-3) expression, we found that an increasing expression of Caspase-3and Bax, and a decreasing express level of bcl-2, if we chose H2O2 as the control group. In the SeHA group we found the contrary result. It confirm the antagonism of SeHA to the H2O2 oxidative damage ,and the antagonism may be enhanced by the increased density of SeHA.We also compared the anti-oxidation activity of SeHA with PZ51,GSH,Vc, give full proof of this fact.Used the Doppler ultrasound to test the basilar artery's blood flow rate in rat mer-skull, found that SeHA can acclerate he basilar artery's blood flow rate as same as Papaverine. It confirm that the therapeutic effect to the animal models of rats with cerebral vasospasml of SeHA delayed release particle and Papaverine are close to each other. TUNEL patho-stain shows that the vessel wall cell apoptosis in SeHA group is less than the SAH group, and close to the control group; the Papaverine group is close to the SAH group. It certify that SeHA can depress the vessel wall cell apoptosis. The test in gene level suggest that the promote apoptosis gene Caspase-3 and Bax have increased expression in both SAH group and Papaverine group, at the same time, have a low expression of bcl-2. The selenylation hyaluronic acid group shows a low Caspase-3, Bax expression level, and a high level of bcl-2 expression. In result, SeHA has preventive effects in cerebral vasospasm and apoptosis in blood vessel Cells.The test confirmed the the against activities of the lipid peroxidation of SeHA, and can reduce the happening of vasospasm, but cant convert the vasospasm that have happened. Compared with the Papaverine and Ca-antagonist (Nimodipine), the SeHA can depress the vasospasm meanwhile inhibate the apoptosis of local brain tissue and vessel wall cell whici is induced by peroxidize injury to improve the long-term prognosis.Conclusion:This study confirm not only the activity of antioxidation of SeHA in cell and organelle level, but also the biological activities and pharmacology effect. And also disscuss the effection of SeHA during the lipid peroxidation damage by a animal model. And then nhibit lipid peroxidation to ease CVS and the apoptosis of vessel wall cell. This study start a new excellent remedy for pathological lesion of neurosystem induced by SAH. We establish an experimental substructure for the SeHA patent in-service use. This study disscuss the pathophysiological mechanism of the cerebral vasospasm happened developed and released. These results made a foundation for the SeHA which a new type of antioxidant drug with high GPX activity in neurosurgey. As the strongest competitor of PZ51 which is now studying in the world, the new drugs based on SeHA will make up a deficiency in our country.