Apolipoprotein A-I Inhibits Increased Activity of Chitotriosidase and β-Glucosaminidase in the Liver of Mice with BCG-Induced Tuberculous Inflammation

The aim of this study was to study the activity of lysosomal chitinases (chitotriosidase and β-glucosaminidase) in the liver of mice on a model of BCG-induced tuberculous inflammation after intravenous administration of apolipoprotein A-I. The study was carried out on CBA male mice weighing 20–22 g. Disseminated tuberculous inflammation was modeled by a single intraperitoneal administration of 0.5 mg of BCG vaccine. The activity of chitinases was determined using 4-methylumbelliferyl-β-D-N,N',N''-triacetylchitotrioside and 4-methylumbelliferyl-N-acetyl-β-D-glucosaminidine fluorescent substrates. BCG infection of animals after 4 weeks caused a significant increase in the activity of endogenous chitinases as compared with the control group. Thus, the activity of chitotriosidase increased by 3.05 times ( p < 0.001), while that of β-glucosaminidase increased by 1.76 times ( p < 0.01). The intravenous administration of apolipoprotein A-I to animals against the background of BCG infection inhibited the increased enzyme activity, the values did not differ significantly from the control values. The results of the conducted studies indicate the ability of apolipoprotein A-I to decrease the increased activity of endogenous lysosomal chitinases in the liver of mice with BCG-induced tuberculous inflammation.