The effect of environmental factors of the coking plant on the enzymatic activity of rabbit oral mucosa.

Histochemical methods were used to investigate the activities of some intracellular enzymes in the oral mucosa of the rabbits which had been kept in selected work-stands of a coking-plant for 3 months. The findings were compared with the results for the enzymatic activity of the oral mucosa of control rabbits. The epithelium of the oral mucosa of the experimental rabbits was found to be proliferated acanthotically; moreover, there occurred some other morphological changes of the mucosa which often resembled precancerous states of leukoplakia type. In comparison with the control group, the activities of the studied enzymes, i.e. reduced NAD dehydrogenase (NADD), glucose-6-phosphate dehydrogenase (G6PD), lactate dehydrogenase (LDS), succinate dehydrogenase (SD), cytochrome oxidase (CO), and phosphorylase a+b in the epithelium and the connective-tissue cells of the studied mucosa of the experimental animals were as a rule markedly lowered, this decline being especially pronounced for the three last-mentioned enzymes. It was only the proliferating stratum basale of the experimental rabbit epithelium that frequently exhibited enhanced activities of NADD and LDS. Besides, the activities of NADD, G6PD and LDS were of a markedly diverse intensity in the cells of the chaotically proliferating stratum spinosum of the experimental rabbit mucosa. The results point to the noxious modifying effect of chemical and physical agents of the investigated environment on the oral mucosa of the animals studied.