Oral exposure to the organophosphorus insecticide, Monocrotophos induces intestinal dysfunction in rats

There is limited experimental evidence to imply the role of organophosphorus insecticides on intestinal
dysfunctions. Residues of Monocrotophos (MCP), above maximum residue limits (MRL), have been
reported in fruits and vegetables from various parts of India. Hence, in this study, we investigated the
potential of MCP to induce intestinal dysfunction in rats. MCP was administered orally to rats at sublethal
doses (0.45, 0.9 and 1.8 mg/kg b.w/d) for 30 days. MCP at the highest dose significantly increased the unit
weight of the small intestine. MCP increased the activities of intestinal brush border disaccharidases,
intestinal alkaline phosphatase, glycyl-glycine dipeptidase, and Na+/K+-ATPase while it decreased cholesterol:
phospholipid ratio. Histology and scanning electron microscopy of small intestine of MCP treated
rats revealed disruption in terms of congestion, increased length of villi, goblet cell hyperplasia, infiltration
of inflammatory cells and necrotic villi tip. Further, the intestinal transit rate was found to be
increased in MCP treated rats. Collectively, our findings provide evidence that repeated oral intake of
MCP has the propensity to alter small intestinal structure and functions, which might lead to intestinal
dysfunctions and abnormal nutrient uptake and thereby affect the human health. Although we have
employed doses, which are higher than those likely to be encountered as residues, we speculate that further
studies should be performed to determine whether MCP residues in foods in the long-term will
interfere with the digestive capacity of the small intestine and thus exert adverse effects on the health
of human.