Neurotoxicological effects of deltamethrin on the postnatal development of cerebellum of rat.

ABSTRACT

Deitamethrin (DLT) has been accepted to be 10,000 times less toxic to man than to insects. While toxicity of DLT in adult animals has been studied using biochemical and electrophysiological tools, reports on its developmental neurotoxicity are rather scanty. Wistar rat pups were exposed to DLT (0·7 mg/kg body wt/day, i.p., dissolved in propylene glycol) from postnatal day 9-13. Equal number of age matched pups were used as vehicle controls. The animals were weighed and perfused intracardially on postnatal days 12, 15, 21, and 30 and their brains dissected out. Cerebellum along with the brainstem was separated by a transverse section at the tectal level and processed for morphometric and toxicological studies. The micro- and inter-neurons in the cerebellum are known to differentiate and mature, both morphologically and biochemically, during the postnatal life of rats. Postnatal exposure to DLT has been observed to delay the cytogenesis and morphogenesis of these neurons. In addition to this, damage to the developing vasculature has also been recorded in the form of thrombus and haemorrhage. Focal degeneration and spongy appearance of the tissue in the vicinity of the damaged blood vessels have also been recorded. The study has opened up several questions on the safety of this substance to the pregnant mothers and infants in the habitats where this substance is in use for vector control.