Assessments of Motor Abnormalities on the Grid-Walking and Foot-Fault Tests From Undernutrition in Wistar Rats

Abstract

ABSTRACT. This study was designed to verify whether different lactation conditions influenced nervous system development. The authors used motor tasks to verify changes in exploratory activity and muscle strength of weaned rats from different litter sizes and evaluated the applicability of the grid-walking test for assessing motor abnormalities caused by undernutrition. Alterations in litter size during the suckling period perturbed the nutritional status of pups, which exhibited body weight differences between the groups. Large-litter (L) pups showed significant delays in achieving developmental milestones and neurological reflexes compared to the small-litter (S) and medium-litter (M) pups. The S, M, and L group pups exhibited similar exploratory responses and muscle strength. In the grid-walking and foot-fault tests, the L group pups traveled shorter distances and, consequently, had less footsteps. However, the percentages of foot faults in the L group were higher than S and M groups. These results reflect delayed maturation of structures responsible for sensorimotor responses, such as the cerebellum, because much cerebellar maturation takes place postnatally. This is the first study to report that early undernutrition in pups resulted in suboptimal performances on the grid-walking and foot-fault tests and that the former test was sensitive to alterations caused by nutritional deficiency.

Keywords:

• early undernutrition
• developmental milestones
• neurological reflexes
• motor development
• grid-walking test
• foot-fault test

ACKNOWLEDGMENTS

The authors would like to thank Mr. Victor Chalupe for helping in the animal breeding process, Mr. José Henrique Vallim for experimental procedure assistance, and Ms. Neusa Domingos for animal care assistance.

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).