Abstract

Objective: To compare long-term cardiac and neurodevelopmental outcomes of early postnatal growth restriction followed by varying degrees of catch-up growth in neonatal rats.
Methodology: This experimental study was conducted at the Anatomy Department, CIMS Multan on 120 neonate Wistar rats. A rodent litter size manipulation model simulated human extrauterine growth restriction (EUGR) and subsequent catch-up growth. For the first 10 days, 30 pups were fed normally (Group N), while 90 were undernourished (Group R) to mimic EUGR. From days 11 to 21, the undernourished rats either had normal growth (RN, n=30) or catch-up growth (RC, n=60). The RC subgroup was further divided into accelerated (RCA) and slow (RCS) catch-up growth based on growth velocity. Somatic growth was assessed throughout the study, and neurodevelopment was evaluated on day 55 using the Y-maze test. On day 60, gross cardiac parameters were assessed after euthanasia. Group comparisons were made using ANOVA.
Results: Undernourished rats with RCA weighed more than normally-fed rats (N) by the end of the catch-up period and continued to weigh more after being shifted to ad libitum feeding. The RCA subgroup exhibited significantly lower neurodevelopment, as measured by the maze test, compared to RN and RCS. Cardiac parameters, including absolute heart weight, heart weight-to-body weight ratio, and standardized heart weight, were significantly higher in RCA and RCA pups compared to RN and N (p

Key words: Extrauterine growth restriction, catch-up growth, neurocognitive, development, cardiac, Y-maze test.