Effects Of Triptolid On Inflammatory Cell Apoptosis In Experimental Autoimmune Encephalomyelitis Induced In Wistar Rats

Experimental autoimmune encephalomyelitis (EAE) is mediated by CD4+ T-lymphocytes and can be induced in susceptible animals by active inoculation with myelin antigens. EAE is characterized by spontaneous recovery and demyelination in the central nervous system (CNS) and destroy of blood-brain-barrier (BBB). EAE is the best available animal model of multiple sclerosis (MS). The present study is designed to induce EAE model in un-susceptive Wistar rats with injection of pertussis toxin in different place. T-cell apoptosis was assessed on brains and spinal cords cross-sections by morphology and TUNEL staining. We also exami ne the effect of dexamethasone (DXM) and triptolid (TP) on inflammatory cell apoptosis in EAE. To find the pathogenesis of the disease for new therapy and theory basis we carry out the study. The present study is made up of two sections. Section one is the induction of EAE. The EAE model is successfully induced by injecting guinea pig CNS homogenate and Complete Freund' sadjuvant (CFA) intracutaneously or subcutaneously to Wistar rats with the dose of 0.4ml per rat. In addition , 5.0×1010 pertussis was administered intraperitoneally or subcutaneousl y on one hind foot to each rat. The incidence of disease was 87. 5%(n=24). Section two is the study of apoptosis of brains and spinal cords in EAE rats and NS-, CFA-, DXM- and TP-treated rats 24 hours after onset of disease. The rats were injected with different drugs while onset of the disease is occured. The results were showed as following:1. The rats with pertussis administered subcutaneously had an attack beginning on 10.25±1.67d p. i. and the incidence of disease was 87. 5%;while the rats with pertussis administered intraperitoneally were 14.8±1.79 d p. i. and the incidence of disease was 35.7%. There was significant difference in the severity of clinical symptoms between two groups (3. 38±0. 74 vs 2. 4±0. 55, P=0. 029<0. 05). The foci in the sections of brains and spinal cords in intraperitoneal group were less and less dense immunofluorescence than those of subcutaneous group.2.There was no difference in incidence of disease, clinical symptoms and the weight change in EAE, DXM and TP groups. The rate of death was much higher in EAE group than DXM, TP groups. There was no difference in DXM and TP groups.3. We used TUNEL method to acquire apoptotic cells. There were almost zero TUNEL-positive cells in NS and EAE groups and a few TUNEL-positive cells in CFA group. The higher TUNEL-positivecells were in DXM and TP groups. There was significant difference (p<0.05) in these three groups. Gone I us i on1. Pertussis is important in EAE induction in un-susceptive Wistar rats and different injection places had different results. Pertussis administered subcutaneously is more suitable to use in China.2. There were little TUNEL-positive cells in EAE 24 hours after onset, which is probably one reason of EAE attack. DXM and TP can induce cell apoptosis of EAE and eliminate of clinical symptoms and lower the rate of death.3. None of rats in CFA group fell sick, and there were a few TUNEL-positive cells in CFA group. It is maybe the result of destroy of BBB.