Study On The Relationship Between Histone Acetylation And Isoniazid Induced Hepatotoxicity In Rat

Objectives To study on the change of histone H3, H4 and HAT, HDAC that isoniazid induced liver injury in rats. To clear histone acetylation of mechanism under the effect of oxidative stress on hepatic injury.Methods Ninety-six adult SD rats were selected and divided into isoniazid groups(forty-eight) and the control group(forty-eight) randomly. Rats from isoniazid groups were injected by isoniazid 55 mg·kg-1·d-1 intragastrically for 3, 7, 10, 14, 21 and 28 days respectively and scarificed finally. Correspondingly, the rats from the control group were killed on the same time point. Their heart were for blood sampling, then the removal of the liver tissue. Pathological examination of liver tissue was observed by HE staining.Western blot was used to measure the expression of H3 ac and H4 ac. The activity of HAT, HDAC and IL-1β, IL-17 were detected by ELISA in liver tissue. Realtime RT-PCR was used to test the expressions of HAT, HDAC and IL-1β,IL-17 m RNA.The level of superoxide dismutase(SOD) and malondialdehyde(MDA) were detected by biochemical method in liver tissue.Results 1 In liver tissue pathological observation showed that liver cells gradually showed the phenomenon of a large number of deaths after 14 d, which proof of isoniazid induced liver injury in rats model was successful. 2 The process of INH induced liver injury in rats can induce oxidative stress, different time points SOD activity decreased,while the content of MDA was significantly increased after 14d(F=3.309, P=0.009;F=55.261, P=0.000). 3 Under the stimulus of INH, the expression of histone H3,H4 is hypoacetylation in liver(P(27)0.05). After ANOVA of factorial design, the INH group and contorl group of histone H3K9 ac, H3K14 ac and H4K5 ac, H4K8 ac level differences was statistically significant(F values were 39.92, 30.335, 141.69, 50.41, P(27)0.001). According to the days of drug increased histone H3K9 ac, H3K14 ac and H4K5 ac, H4K8 ac level differences was statistically significant( F=3.734, P=0.004; F=2.394, P=0.044;F=2.41,P=0.043;F=2.45,P=0.04). There were interaction effects between INH and the number of different days of administration(F=2.364, P=0.047. F=2.63, P=0.029.F=2.32, P=0.05), except for histone H3K9(F=0.405, P=0.844). 4 Further study of HAT and HDAC protein content and m RNA that regulates histone H3, H4 acetylation. Theexpression of HAT and HDAC protein was consistent with the degree of acetylation of histone, and the corresponding relationship between m RNA changes and protein expression was also obvious(F values were 87.34, 36.785, 120.772, 337.302,P(27)0.001).There were significant differences in the expression of CBP/P300, HDAC1, HDAC2,HDAC3 and m RNA in different administration day(F=2.385, P=0.045; F values of HDAC were 11.867, 4.977, 13.496, P(27)0.001). Changing of CBP/P300 and HDAC1,HDAC2, HDAC3 was correspod to histone H3 ac and H4 ac and interferes with the histone acetylation level, which influences the process of liver injury induced by isoniazid. 5 A large number of inflammatory cytokines IL-1β and IL-17 were secreted under the stimulation of INH( F values were 292.125, 311.828, P(27) 0.001). The expression of IL-1β, IL-17 and m RNA in different administration days had statistical significance(F values were 14.220, 4.528, P(27)0.001).Conclusions 1 Histone acetylation involved in the process of liver injury induced by isoniazid. 2 In the process of liver injury in rats induced by isoniazid, oxidative stress interferes with the histone acetylation level and influences the balance between HAT and HDAC, then induces inflammatory factor excess production.