Early life exposure to poly I:C impairs striatal DA-D2 receptor binding, myelination and associated behavioural abilities in rats.

ABSTRACT

Early-life viral infections critically influence the brain development and have been variously reported to cause neuropsychiatric diseases such as Schizophrenia, Parkinson's diseases, demyelinating diseases, etc. To investigate the alterations in the dopaminergic system, myelination and associated behavioral impairments following neonatal viral infection, the viral immune activation model was created by an intraperitoneal injection of Poly IC (5 mg/kg bw/ip) to neonatal rat pups on PND-7. The DA-D2 receptor binding was assessed in corpus striatum by using 3H-Spiperone at 3, 6 and 12 weeks of age. MOG immunolabelling was performed to check myelination stature and myelin integrity, while corpus callosum calibre was assessed by Luxol fast blue staining. Relative behavioral tasks i.e., motor activity, motor coordination and neuromuscular strength were assessed by open field, rotarod and grip strength meter respectively at 3, 6 and 12 weeks of age. Following Poly IC exposure, a significant decrease in DA-D2 receptor binding, reduction in corpus callosum calibre and MOG immunolabelling indicating demyelination and a significant decrease in locomotor activity, neuromuscular strength and motor coordination signify motor deficits and hypokinetic influence of early life viral infection. Thus, the findings suggest that early life poly IC exposure may cause demyelination and motor deficits by decreasing DA-D2 receptor binding affinity.