The Role Of HSP70 In Reactive Astrocytosis After Astrocytes Were Injured

Objective: (1)To study the role of HSP70 in reactive astrocytosis and the production of BDNF after astrocytes were injured .(2) To clarify the role of HSP70 in the formation of glial scar.Methods: Astrocytes were prepared from newborn rat cerebral cortex and evaluated the purity by immunocytochemical staining for GFAP. The astrocytes injury model was made by means of surgical blade scraping. Injured astrocyes were divided into two groups: the anti-HSP70 group was added neutralizing antibody against HSP70 ;the control group was added degermed PBS. Uninjured astrocytes was the normal group. Immunocytochemical staining for GFAP and BDNF were performed on each group at the time of 30min,24h,4d and 7d post injury. The immunocytochemical staining photographs were analyzed by image analysis system, obtaining average optical densities , average cell area, average number of dentrites and average dentritic length of astrocytes. At same times,the total RNA of three groups were extracted,then the expression of GFAPmRNA and BDNFmRNA were studied by RT-PCR. Results: (1) The purity of cultured astrocytes is 97.83%; (2) Astrocytes injured by scratch injury model showed the same morphologic changes as other modles in domestic and foreign studies.(3) The immunocytochemical staining for GFAP showed that the average cell area,average dentritic length and average number of dentrities of astrocytes in the anti-HSP70 group were significantly lower than the control group(P<0.05). The average optical densities of immunocytochemical staining for BDNF in the anti-HSP70 group were obviously lower than the control group(P<0.05). (4)Compared with the control group,the expresstion of GFAPmRNA and BDNFmRNA in the anti-HSP70 group were down-regulated (P<0.05).Conclusion: (1) The purity of cultured astrocytes was above 95%;(2) The astrocytes injury model had been achieved successfully by scraping; (3) HSP70 plays an important role in reactive astrocytosis; (4) The reactive astrocytosis can be controlled to some extent by blocking HSP70 with neutralizing antibody which would suppress the formation of glial scar; (5) HSP70 plays a role in reactive astrocytosis mainly through the C-terminal; (6) Production of BDNF can be reduced following the surpression of reactive astrocytosis;...