Effects of neem (azadirachta indica) on vascular development in chick embryo area vasculosa.
Kweri, J. K.
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Background: Neem is increasingly being used widely even by expectant mothers in many human products. Yet, its teratogenic effects are being queried since it has been observed to cause anaemia in mature chicks and a wide array of congenital defects in rat, frog embryos and other laboratory animals depending on the doses applied. However, its effects in chick embryo had not been established. Objective: To determine the effects of neem extracts on vascular development in a chick embryo area vasculosa in-vitro. Design and setting: The study was an experimental cohort study carried out in the department of Anatomy, Makerere University. A population of 256 embryo explants were studied. Findings: Neem extracts at doses of 20, 50, 100, 200 and 250µg/embryo were used. The lower doses caucused effects that were related to the stage of embryo development as well as the duration of exposure to the neem cultures. However, doses of 150µg and above were observed to significantly inhibit normal vascular development and the expansion of area vasculosa in a manner that was dependent on duration of exposure but not the dose or stage of embryo development. Blood islands continued to form but their assembly was inhibited, indicating neem interference with the mechanism regulating vascular cellular endothelium, hence its effects were on vasculogenesis and not angiogenesis. Supplementation of neem treated cultures with 354 mmols of Myo-inoisital completely alleviated effects of neem in a dose dependant manner up to a dose of 150µg indicating that phosphatidylinosital second messenger cycle (PI) is involved in vasculogenesis. 62.7% of the embryos so supplemented with myo-inosital remained normal. Supplementation with myo-inosital beyond 6 hours of exposure to neem or above a dose of 150µg neem showed no alleviatory effects. Control explants in both the normal saline and the untreated did not show any significant difference (p=0.0081) as they developed normally but only recording abnormalities in 6.2% that could be attributed to environmental and genetic factors. Conlcusion: Neem is a teratogenic agent in the early stages of vascular development, in a chick embryo depending on doses applied and the embryo stage of development. Recommendation: further studies should be carried out with mice, guinea pigs, rabbits because they are mammals with close relation to humans with a view to establishing the neem teratogenic linkages to humans. Additionally, studies at molecular and genetics level should be conducted to find out the genes involved.