Estrogen Eae Rat Cell Apoptosis, Regulation Of Gene Expression Of Bcl-2, Bax

ObjectiveTo establish the Wistar rats ovariectomized model of experimental autoimmune encephalomyelitis(EAE),observe the effects of Estradiol(E₂) on EAE,explore Bcl-2, Bax expression and apoptosis of inflammatory infiltrating cells in the rats' central nervous system(CNS) with EAE after dealing with E₂.Methods1.EAE was induced by being injected guinea pig spinal cord homogenate(GPSCH) in complete Freund's adjuvant(CFA) in four footpads and bordetella pertussis vaccine(BPV) in one footpad.The female Wistar rats were randomly divided into control group,EAE group and E₂ group.From day 0 postimmunization(pi.) to day 20 pi.,the rats ovariectomized in E₂ group were treated with an intramuscular injection of E₂(500μg/kg·d),and the rats in control group and EAE group were treated with an intramuscular injection of peanut oil of the same volume.The clinical and histological manifestation of the disease was observed in each group until 30 days pi.The levels of E₂ in serum was measured with radioimmune assay.2.The rats were executed on day 3 postmorbidity.The inflammatory infiltration cells in the CNS were counted under the microbioscope and the apoptosis of them were detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling(TUNEL). Immunohistochemical staining was used to measure the expression of Bcl-2,Bax protein of the inflammatory infiltrating cells.The levels of E₂ in serum was measured with radioimmune assay.Results1.The disease did not appear in rats administered by complete Freund's adjuvant and physiological saline and the weight of the rats increased.In EAE group,morbidity is 83.3%, incubation period is 12.10±0.99 days,duration of symptom is 14.00±1.15 days,the maximum clinical score is 3.10±0.99,the maximum weight decrement is 28.50±1.85g.In E2 group, morbidity is 33.3%,incubation period is 15.50±1.29 days,duration of symptom is 12.00±0.82 days,the maximum clinical score is 1.50±0.58,the maximum weight decrement is 22.68±1.53g.The differences of morbidity,incubation period,duration of symptom,the maximum clinical score and the maximum weight decrement between EAE group and E₂ group were statistically significant(p＜0.05).The concentration of E₂ was 11.53±2.87pmol/l,10.62±1.35 pmol/l,78.25±0.46 pmol/l respectively in control group,in EAE group,and in E₂ group.The differences of concentration of E₂ between control group and EAE group weren't statistically significant(p＞0.05).The differences of concentration of E₂ between E₂ group and EAE group were statistically significant(p＜0.01).2.The rats of control group hasn't obviously abnormal pathological change.In EAE group, the inflammatory infiltrating cells around blood vessel are 70.19±20.79,apoptotic cells are 5.26±4.43,apoptosis rate is 13.34%.In E₂ group,the inflammatory infiltrating cells around blood vessel are 42.35±24.38,apoptotic cells are 6.08±3.50,apoptosis rate is 6.97%.The differences of inflammatory infiltrating cells,apoptotic cells and apoptosis rate between EAE group and E₂ group were statistically significant(p＜0.05).In EAE group,integral optical desity of Bcl-2 of each infiltrating cell is 49.29±18.23,integral optical desity of Bax of each infiltrating cell is 25.38±17.85,Bcl-2/Bax is 2.28±0.65.In E₂ group,integral optical desity of Bcl-2 of each infiltrating cell is 30.33±16.75,integral optical desity of Bax of each infiltrating cell is 26.75±14.41,Bcl-2/Bax is 1.24±0.13.The differences of integral optical desity of Bcl-2 of each infiltrating cell and Bcl-2/Bax between EAE group and E₂ group were statistically significant(p＜0.05).The differences of integral optical desity of Bax between EAE group and E₂ group weren't statistically significant(p＞0.05).In EAE group,the concentration of E₂ was 17.43±2.36 pmol/l,in E₂ group,the concentration of E₂ was 2983.21±162.78 pmol/l. The differences of concentration of E₂ between E₂ group and EAE group were statistically significant(p＜0.01).Conclusion1.The method of establishing the EAE with both CFA-GPSCH and BPV is stable.E₂ can efficiently protect rats from disease progression in EAE rat model.2.E₂ may inhibit inflammatory infiltration and induce apoptosis of inflammatory infiltrating cells in the CNS of EAE rat model,which might be associated with its contribution to suppress the expression of Bcl-2 protein and decline the rate of Bcl-2/Bax.