Experimental evaluation of cytoprotective effect of probiotic metabolites and selection criteria of Bacillus Subtilis strains for development of new immunotropic biohepatoprotector

The present work concerns a study of cytoprotective effect of biologically active substances (BAS) produced by probiotic microorganisms from the Bacillus genus. These substances were obtained from a sterile fugate of probiotic Bacillus subtilis VKPM B-3679 culture (a biosporicin-producing strain) and added to the culture of isolated hepatocytes, when modeling their in vitro toxic damage. Sterile buffered culture of Bacillus subtilis B-3679 was prepared by sterilizing filtration of the culture supernatant of this strain. The work was carried out using a passageable L-41 cell culture strain, which allows to assess toxicity of various substrates upon cell cultures and protection against toxic effects at different concentrations. At the first stage of study, the maximal non-toxic dose of sterile fugate and the minimal toxic dose of CCl4 established for the cultured L-41 cells. At the next stage, cytoprotective effect of BAS originating from the of B. subtilis B-3679 strain fugate, was studied and tested with L-41 cell line. Cytoprotective and regenerative effects of BAS containing in the fugate of B. subtilis B-3679 strain were demonstrated in the model of toxic damage using the culture of isolated hepatocytes. In preclinical studies, to assess the toxicity and safety of the experimental sample of a new biohepatoprotector for experimental animals, we have found that the complex of biologically active substances (metabolites) is non-toxic and safe for laboratory animals when administered intragastrically and intraperitoneally, and it does not cause any pathological changes in their internal organs and tissues. The basis of the new biohepatoprotection effect, which may provide a multifunctional action, allowing to effectively restore depressed liver functions, with simultaneous normalization of immunological parameters, is its active biocomponent, i.e., metabolites of probiotic spore-forming bacteria, which, when if brought to the body, produce a complex of biologically active metabolites (antibiotics, proteolytic, amylolytic, and other enzymes, immunoglobulins, as well as interleukins, vitamins, proteins, amino acids, and others bioactive substances). Due to experimentally established cytoprotective effect of the complex of BAS, the components of fugate culture of B. subtilis strain B-3679, will allow us to develop new promising medical immunobiological drugs that may provide a protective effect on human organs and tissues. As a result it was found that BAS, as components of fugate from B. subtilis B-3679 strain show both a pronounced cytoprotective effect, and a positive action upon regenerative abilities of liver cells, which is a significant factor for the future use of this strain as a biocomponent of a new immunotropic biohepatoprotector.