Destructive Processes and Fibrotic Complications in the Liver of Mice with BSG-Induced Granulomatosis Treated with Anti-Tuberculous Drugs

Three months after infection with Mycobacterium tuberculosis (MBT) from BCG vaccine, male BALB/с mice were treated with isonicotinic acid hydrazide, dextrazide (oxidized dextran), and liposome-encapsulated dextrazide intraperitoneally or in inhalations in a dose of 14 mg/kg (calculated for isoniazid) twice a week for 6 months. All these drugs exhibit different antimycobacterial efficiency. In the liver parenchyma, an up to 5-fold decrease in the number of destructed hepatocytes was observed depending on the efficiency of treatment. No destructive processes were observed in granulomas. Type I and III collagens were revealed around the granulomas; their content in the liver parenchyma was negligible. TNFα, IL-6, MMP-1, ТIMP1 were expressed only by granuloma macrophages. As the number of damaged hepatocytes and size of inflammatory infiltrates in the liver parenchyma decreased, the content of both types of collagen decreased. No evidence of hepatotoxicity of MBT degradation products in macrophages in vivo was obtained; the assumption that fibrotic complications are only the post-destruction process was not confirmed. Fibrotic complications are supposed to be an “excessive” systemic nonspecific adaptive process aimed at the maintenance the so-called structural homeostasis initiated by activated М2-macrophages in granulomas.