SEM study on cytotoxic effect of monocrotophos (MCP) on lungs of rat.

Monocrotophos (MCP) on oral administration (0.28 mg/100 g of body wt. i.e. 1/5th of LD50) to female rats for 15 and 30 days damaged alveolar walls lined by type II cells (great alveolar cells); clara cells (non-ciliated cells) lining bronchiolar epithelium; and emphysematous lesions due to loss of inter-alveolar walls. This led to increase in surface tension in lung due to decrease in secretion of surfactant as a result of necrosis of great alveolar cells and clara cells resulting in hypoxia. This effect was time dependent. In R group (15 days without pesticide after 30 days daily oral treatment), the toxic effects mentioned above still persisted which revealed non-repair of necrosis caused by MCP.