| ObjectiveTo establish the rat model of liver injury induced by isoniazid and rifampin and investigate the effect of pyrrolidine dithiocarbamate (PDTC) on isoniazid-rifampin-induced liver injury in rats and its possible mechanism.Methods48 male SD rats(SPF grade) were randomly divided into three groups, normal group, model group and PDTC group. Model and PDTC group were intragastrically given isoniazid 50mg/(kg·d)+rifampin 50 mg/(kg·d) on an empty stomach once daily. Normal group was given equivalent 0.9% sodium chloride. Additionally, PDTC group was given PDTC 50 mg/(kg·d) by intraperitoneal injection, the other two groups received daily intraperitoneal injections of the equivalent 0.9% sodium chloride.8 rats in every group were randomly sacrificed on day 14, The remaining rats in every group were sacrificed after 28 days of continuous above-mentioned treatment. The serum alanine aminitransperase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), total biliary acid (TBA), total bilirubin (TBIL), direct bilirubin (DBIL) were measured. Oxidative stress and lipid peroxidation were assessed by measuring malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity in liver. Histopathological and ultrastructural changes of liver tissues were observed Expression of HMGB1 was detected by Immunohistochemistry. The hepatic mRNA expression of tumor necrosis factor (TNF)-a and bile salt export pump(BSEP)were evaluated by RT-PCR analysis. Electrophoretic mobility shift assay (EMSA) was performed to detect NF-κB activity.Results(1) In comparison with normal group, the serum levels of TBA, TBIL, DBIL, ALP in model group were significantly increased (P<0.01),the activities of ALT and AST were not significantly different(P>0.05);Hepatocyte fatty change,inflammatory cell infiltration in rat livers of model group were observed(P<0.01), damaged structure of mitochondria and endoplasmic reticulum of liver cell, increasedlipiddroplet in cytoplasmic were also observed under the transmission electron microscope; hepatic SOD activity was significantly decreased (P<0.01), MDA content was significantly increased(P<0.01) in model group; the expression of HMGB1 was elevated(P<0.01),and increased expression of HMGB1 is more remarkable on day 28 than that on day 14(P<0.01); TNF-a mRNA was significantly up-regulated and BSEP mRNA was significantly down-regulated(P<0.01); The activity of NF-κB in rat liver tissues was elevated in model group,especially on day 28(P<0.01).(2) In comparison with model group, the serum levels of TBA, TBIL, DBIL, ALP in were significantly decreased in PDTC group(P<0.01);Histopathological and ultrastructural changes of liver tissues were improved significantly(P<0.01); hepatic SOD activity was significantly increased and MDA content was significantly decreased in PDTC group(P<0.01); the expression of HMGB1 was notably reduced; TNF-a mRNA was significantly down-regulated and BSEP mRNA was significantly up-regulated (P<0.01); The activity of NF-κB in rat liver tissues was reduced in PDTC group,and the difference was statistically significant on day 28(P<0.01).Conclusion(1) The activity of NF-κB was elevated in isoniazid-rifampin-induced liver injury in rats and inhibition of NF-κB attenuated hepatic injury effectively,indicated that NF-κB played an important role in isoniazid-rifampin-induced liver injury. (2) Inhibition of NF-κB by PDTC exerts a therapeutic effect on isoniazid- rifampin-nduced liver injury may be associated with antioxidant action, reduced expression of HMGB1, decreasing the expression of TNF-α mRNA and increasing the expression(3) Isoniazid and rifampin combination enhanced hepatic HMGB1 expression, translocation from the nucleus to the cytoplasm, which indicated HMGB1 play a key role in the pathogenesis of isoniazid- rifampin-induced liver injury. |
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