In vitro induction of 60-kDa and 70-kDa heat shock proteins by endosulphan and monocrotophos in sheep blowfly Lucilia cuprina.

The effect of two most commonly used and highly toxic organic pesticides, endosulphan (organochlorine) and monocrotophos (organophosphate), was studied in a blowfly, Lucilia cuprina, to test whether these pesticides induce the stress response and, if so, whether the intensity of the response, in terms of induction of heat shock proteins (HSPs), HSP60 and HSP70 in particular, is pesticide concentration dependent. The in vitro exposure of larval and adult tissues to varying concentrations of these pesticides (endosulphan: 1.0-4.0 ppm for larva and 0.05-0.50 ppm for adult; monocrotophos: 0.0005-0.0050 ppm for larva and 0.0001-0.0010 ppm for adult) revealed that both compounds were able to induce the expression of HSP60 and HSP70 proteins. Western blot analysis of these HSPs indicated that the induction of expression was tissue-specific. The trypan blue staining of pesticide-exposed tissues demonstrated monocrotophos to exert more severe effect than endosulphan, as the former compound induced both HSP60 and HSP70 significantly at a much lower concentration than that of the later. The pattern of expression of these HSPs, in general, appeared in direct correlation with the pesticide concentration. Gut tissues were found relatively more sensitive to pesticide toxicity than other tissues, as revealed by trypan blue staining, and hence, they might serve as primary targets for early detection of pesticide toxicity. The results indicated that either of these HSPs or both could serve as a potential biomarker toward assessment and monitoring of toxicity induced by these pesticides.