Function And Mechanism Study Of Microglia In Herpes Simplex Virus Encephalitis

Objective: In order to know the characteristics of the three courses of immune responses in herpes simplex virus encephalitis (HSE) of Balb/c mouse.Methods: Balb/c mouse were made HSE by injecting herpes simplex virus type I(HSV1) and their brain tissues were obtained. Pathologic slices of brain tissues of mice were used to identify their morphologic difference. The surface antigens on microglia such as CD11b, CD40, MHCI and MHCII were measured by flow cytometry and semiquantitative reverse transcription polymerase chain reaction (RT-PCR) were used to detect the mRNA of IL-2, IL-4, IL-10, TNF-α and iNOS in mice's brains. The results of the experiment were operated by Student Test with SPSS10.0 software.Results: After herpes simplex virus typel (HSV1) infection, the lesions of haemorrhage and necrosis in mice's brains could be observed by microscope, and the expression levels of surface antigen CD11b CD40, MHCI MHCII and mRNA of IL-2, IL-4, IL-10, TNF-α and iNOS increased.Conclusions: Microglial cells play important roles in HSE as antigen presenting cells: they are in activation and proliferation and they present surface antigens such as MHC and CD40 in favor of microglia presenting virus antigens and lymphocyte permeating blood-brain barrier and microglia reactivating, secreting cytokines. T_H1 type cytokines and T_H2 type cytokines both play important roles in HSE and they modulate and restrict quantities of each other. Peroxidation is an important aspect in HSE.PART II Study of Immune Mechanism in Herpes Simplex VirusEncephalitisObjective: To find the way of endocellular and extracellular signals in microglia activation and its cytokines secretion.Methods: Balb/c mouse were made HSE by injecting herpes simplex virus type I(HSV1) and their brain tissues were obtained. The dilution concentrations of medication for BV2 cells were determined by MTT method. BV2 cells were inoculated with HSV1 and then medicated by several drugs including ERK and P38 MAPK inhibitor. The mRNA of IL-2, IL-4, IL-10, TNF-α and iNOS in mice brains and BV2 cells were measured by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and their quantities were compared between mice's brain and BV2 cells. Western blot was used to know the presentation JNK MAPK in BV2 cells before and after HSV1 inoculation. The results of the experiment were operated　by Student Test with SPSS 10.0 software.Results: There are much comparability in the characteristics of mRNA changes of many cytokines and iNOS. P-JNK was increased after HSV1 inoculation. PD98059 (inhibitor of ERK MAPK) and SB203580(inhibitor of P38 MAPK) could improve the survival rate of infected BV2 cells and decreased TNF mRNA expression. Aspirin and dexamethasone could decrease iNOS mRNA expression.Conclusion: BV2 cells could be the substitute of mice in HSE study. 3 routes of MAPK(JNK, ERK and P38 MAPK) are all play roles in immune responses of HSE. ERK and P38 MAPK are concerned with the TNF mRNA expression in HSE and TNF is thought to lead to the death of HSV1 infected BV2 cells. Aspirin and dexamethasone may have the ability of nevous protection for their anti- peroxidation.PART III Study of Curative Effect of Six Medicines in HerpesSimplex Virus EncephalitisObjective: To find out the remedial roles and effects of cytokines secretion of several medicines including astragalus, interferon-β cerebroprotein hydrolysate, deproteinized calf blood extractives, dexamethasone and aspirin in HSE.Methods: Balb/c mouse were made HSE by injecting herpes simplex virus type I(HSV1) and BV2 cells were made the cell model of HSE by inoculating HSV1. The dilution concentrations of medication for BV2 cells were determined by MTT method. Cell's survival rate were measured by MTT method and cytokine's mRNA such as IL-2 IL-4 IL-10 TNF-α iNOS were measured by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). The surface antigens on microglia such as CD11b, CD40, MHCI and MHCII were detected by flow cytometry. The results of cell's survival rate, mRNA of cytokines and surface antigens of before and after virus infection and medication were compared.Results: Astragalus, interferon-β and cerebroprotein hydrolysate can makedly improve the survival rate of BV2 cells and Balb/c mice infected with HSV1 and can reduce the cytokines expression including both T_H1 and T_H type cytokines; aspirin, deproteinized calf blood extractives and dexamethasone cannot improve the survival rate of BV2 cells and Balb/c mice infected with HSV1 and cannot reduce the cytokines expression including both T_H1 and T_H type cytokines.Conclusion: Improve the ability of immune response is of primary importance in initial stages of HSE and medicines of restraining immune response such as aspirin and dexamethasone, which made cells could not control the reproduction of virus, result in more severe damages and higher expression of cytokines after several days and should not be used in initial stages. Under the circumstances of virus control, these medicines could be chosen to meliorate the damage of immune response. There are different functions on immune regulation for different medicines.PART IV Prognosis Assessment and Medication in Treatment ofHerpes Simplex Virus EncephalitisObjective: To find effective tools to guide the prognosis assessment and medication.Methods: Cell's survival rate were measured by MTT method and cytokine's mRNA such as IL-2 IL-4, IL-10 TNF-α iNOS were measured by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). These data were analyzed by regression analysis and neural networks and the results of the prognosis analyzed by two methods were compared with actual survival rate in order to find the better way of prognosticating survival rates.Results: A simple regression equation was obtained by regression analysis and its according rate to actual survival rate is 19%, while the data of prognosticate survival rate obtained by neural networks had much higher according rates(75%) to actual survival rates.Conclusion: Neural networks can prognose the survival rates exactly after training for it can efficiently analyze complicated nonlinear relation between the quantities of cytokines. Neural networks should be an effective tool in HSE treatment to guide the prognosis assessment and medication.