Morphometric studies of cardiac myocytes of rats chronically treated with an organophosphate.

Organophosphate intoxication induces an acute cholinergic syndrome, but the long-term effects of these compounds in the cardiocirculatory system are not known. The objective of the present work is to investigate if experimental chronic exposition to repetitive sublethal doses of organophosphate methamidophos can induce morphological changes in rat's hearts. Wistar albino adult male rats received a weekly enteral sublethal dose of the organophosphate methamidophos for 12 consecutive weeks. After that we have performed histological and morphometric studies of their hearts. We have observed hypertrophy of cardiac myocites in treated animals, which was confirmed by morphometric studies (measure of smaller diameter of cardiac myocites). One of the possible explanations for the cardiac hypertrophy would be persistent systemic arterial hypertension in treated animals. However, another possible explanation would be direct sympathetic stimulation.