Chlorpyrifos and its metabolite modulates angiogenesis in the chorioallantoic membrane of chick embryo

: Background Chlorpyrifos (CPF) is an organophosphate insecticide, acaricide, and miticide used primarily to control foliage and soilborne insect pests on a variety of food and feed crops. Since trace amounts of these compounds are found in water and food products, they easily enter into the organ system unnoticed. In the same way, the compound or its metabolite gets transmitted from the parent to the embryo mainly through blood vessels. Since blood vessels form the major route of transport, it is pertinent to study the effect of these compounds during angiogenesis. The effect of CPF and 3,5,6-trichloro-2-pyridinol (TCPy) on the angiogenesis of chick embryo was evaluated in the chorioallantoic membrane (CAM) using an ex vivo model. Methods Nine-day-old incubated eggs where inoculated with various doses of CPF and TCPy. After 48 h of incubation, the CAM layers were retrieved and analyzed using angiogenesis software to obtain the density of blood vessels. Histomorphometric studies were performed to measure the thickness of vessel walls. The expression of VEGF, VEGFR2, and N-cadherin genes responsible for angiogenesis were analyzed. Results The exposure to the parent compound CPF and its metabolite TCPy promoted angiogenesis in groups administered with lower concentration of the pesticide and its metabolite, whereas a decline in angiogenesis was observed at higher concentrations. These observations were made by analyzing the density, histomorphometry results, and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) results. The density, thickness, and lumen size of blood vessels in the groups with low concentration of CPF and TCPy were 28.34, 9 μm, and 30 μm, respectively, whereas in the groups with higher CPF and TCPy concentrations, they were 12, 3 μm, and 9 μm, respectively. Conclusions Hence, CPF and its metabolites interfere with angiogenesis in the CAM of chick embryos. Because of their estrogen-mimicking ability, pesticides are the prime etiological suspects of increasing alteration in blood vessel formation. These results may be of help in future studies on the effect of CPF in embryonic growth, wound healing, diabetes, and tumors.