Effect of Chlorpyrifos On The Skeletal System Development Of Chick Embryo

Abstract

newline Introduction: Chlorpyrifos is an organophosphate insecticide, acaridae and miticide used primarily to control foliage and soil-borne insect pests on a variety of food and feed crops. Humans are exposed to such pesticides through the food they intake, the air they breathe and even by the nature of their job, they get exposure and get affected adversely. While the influence of Chlorpyrifos effects on humans has been widely documented, but less is known about its influence on bones. newlineAim: To analyze the effect of chlorpyrifos and its metabolites (3,5,6-trichloro-2-pyridinol) on the skeletal system of the chick embryo. newlineMaterials and methods: Fertilized Leghorn eggs were obtained from the Poultry Research Station (PRS), Madhavaram and were incubated in a humidified incubator (Hamburger and Hamilton) (Misske et al., 2007). The test substances used were chlorpyrifos (99.9% purity) and its metabolite 99.7% of 3, 5, 6 trichloro-2-pyridinol (Sigma Aldrich, Chennai, India). All other reagents used were of the highest analytical grade were dissolved in 0.9% sterile saline. The chick embryos were exposed to different concentrations of CPF and TCPy or 0.9% sterile saline (control) for1.5days was carefully injected into a small hole made in the air chamber of the egg until day 18. The surviving embryos were harvested for skeleton stainings like histopathology, Immunohistochemistry, Angiogenesis assay and Gene expression study. newlineResults: Exposure to parent compound chlorpyrifos and its metabolite 3, 5, 6 trichloro-2- pyridinol shows dose depended on variations in developing bone of chick embryo. H and E staining of proximal phalanx showing reduced in the total length of the phalanx and increased in growth plate length. Mineralized parts of the phalanx were decreased in CPF and TCPy exposed groups when compared to control. Cell proliferation was more in the proliferative zone, whichever exposed to CPF and TCPy exposed. Apoptotic cells in the hypertrophic zone were reduced in CPF and TCPy exposed group, which in turn reduce the mineralization capacity of Phalanx. In bones, blood islands reduced which directly proposal to decreased mineralization in CPF and TCPy exposed group. newlineConclusion: We have used invivo experimental approaches to demonstrate that CPF and TCPy exposure shortened embryonic long bones. CPF and TCPy exposure alters the chondrogenesis and apoptosis of chondrocytes in the growth plate. CPF and TCPy interfere in ossification by inhibiting the vascular invasion and reduce the mineralization capacity of bones. Gene expressions for the development of bones are down-regulated, followed by the exposure of CPF and TCPy. newlineKeywords: Chlorpyrifos, 3, 5, 6-trichloro-2-pyridinol, Phalanx, mineralization, bone length. newline