Hepatotoxicity Induced by Isoniazid-Lipopolysaccharide through Endoplasmic Reticulum Stress, Autophagy, and Apoptosis Pathways in Zebrafish

Isoniazid (INH) is a first-line antituberculosis drug. The incidence of adverse reactions accompanied by inflammation in the liver during drug administration to tuberculosis patients is high and severely affects clinical treatment. To better understand the mechanism of hepatotoxicity induced by INH under the inflammatory state, we compared the differences in levels of hepatotoxicity from INH between normal zebrafish and zebrafish in an inflammatory state to elucidate the hepatotoxic mechanism using different endpoints such as mortality, malformation, inflammatory effects, liver morphology, histological changes, transaminase analysis, and expression levels of certain genes. The results showed that the toxic effect of INH in zebrafish in an inflammatory state was more obvious than that in normal zebrafish, that liver size was significantly decreased as measured by liver fatty acid binding protein (LFABP) reporter fluorescence and intensity, and that alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were significantly increased. Hematoxylin and eosin (HE) staining and electron microscopy showed that hepatocyte injury was more obvious in the inflammatory state. In the inflammatory state, INH significantly increased the expression levels of endoplasmic reticulum stress (ERS)-related factors (GRP78, ATF6, PERK, IRE1, XBP1s, GRP94, and CHOP), autophagy-related factors (be-clin 1, LC3, Atg3, and Atg12), and apoptosis-related factors (caspase-3, caspase-8, caspase-9, Bax, p53, and Cyt) in larvae. Correlational analyses indicated that the transcription levels of the inflammatory factors interleukin-1b (IL-1b), tumor necrosis factor beta (TNF-beta), cyclooxygenase 2 (COX-2), and TNF-alpha were strongly positively correlated with ALT and AST. Furthermore, the ERS inhibitor sodium 4-phenylbutyrate (4-PBA) could ameliorate the hepatotoxicity of INH-lipopolysaccharide (LPS) in zebrafish larvae. These results indicated that INH hepatotoxicity was enhanced in the inflammatory state. ERS and its mediated autophagy and apoptosis pathways might be involved in INH-induced liver injury promoted by inflammation.