The Effect of Malnutrition on Hippocampal Neuronal Density in Juvenile Wistar Rats: An Experimental Model Relevant to Northeastern Nigeria

Malnutrition during early development is associated with cognitive impairment, and neuroanatomical correlates of this impairment are increasingly being identified in animal models. The hippocampus, a brain structure central to learning and memory, is particularly vulnerable to nutritional deprivation during the critical period of brain growth. The North East geopolitical zone of Nigeria has among the highest rates of childhood malnutrition in the country, yet experimental anatomical data specifically modelling this nutritional context remain limited. This study aims to evaluate the effect of protein-energy malnutrition on hippocampal neuronal density and morphology in juvenile Wistar rats. Forty Wistar rat pups will be randomised into a malnourished group receiving a 5 percent protein diet and a control group receiving a standard 20 percent protein diet for eight weeks. At sacrifice, histological sections of the hippocampus will be prepared using haematoxylin and eosin and cresyl violet staining. Neuronal density, nuclear diameter, and pyramidal cell layer thickness will be quantified in the CA1, CA2, CA3, and CA4 fields using stereological methods. The study anticipates demonstrating measurable reductions in hippocampal neuronal density in the malnourished group, providing a neuroanatomical basis for cognitive deficits observed in malnourished Nigerian children.

Keywords: malnutrition, hippocampus, neuronal density, Wistar rat, developmental neuroscience