Analysis of the influence of biphenyl, chlorinated/chlorohydroxybiphenyls, and their biotransformation products on the immune response and morphofunctional state of the liver

It has been established that biphenyl and PCB 12 (3,4-dichlorobiphenyl) suppressed humoral immunity by reducing the number of antibody-producing cells in the spleen. After microbial degradation of the investigated compounds by the Rhodococcus ruber 25 strain over 7 and 14 days, the metabolites of PCB 12 and biphenyl continued to exert an inhibitory effect on the number of antibody-producing cells. Mixture R, consisting of chlorinated and hydroxylated derivatives of biphenyl, did not influence the humoral response but stimulated the cell-mediated response; this effect was negated following microbial degradation. Histological studies indicated that biphenyl, PCB 12, and mixture R led to the development of chronic hepatitis in the liver, characterized by signs of fatty and focal hydropic (centrolobular) dystrophy of hepatocytes. Vascular responses were observed, including congestion with signs of hemolysis of erythrocytes. Perivascular lymphohistiocytic infiltration was noted. Under the influence of metabolites formed during the degradation of the investigated compounds by the R. ruber P25 strain over 7 to 14 days, dystrophic changes in hepatocytes persisted (without necroinflammatory reaction), and signs of reparative regeneration developed.