Effect of undernutrition and rehabilitation on the postnatal growth of skeletal muscle and nerve in the rat
Gopinath, G.; Roy, S.; Karmarkar, M.G.
Indian Journal of Medical Research 77: 702-712
1983
ISSN/ISBN: 0019-5340 PMID: 6618542 Document Number: 206861
The effects of undernutrition on the skeletal muscle and peripheral nerve were studied in neonatal rats on the 10th, 15th, 20th and 40th postnatal days. Undernutrition was induced by increasing the litter size and reducing the suckling time or diet. The tissues were also studied from 40 day-old rats rehabilitated after 10, 15 and 20 days of undernutrition. Significant reduction in the body weight and muscle diameter were recorded in the undernourished rats. Diameter reduction was more marked after the 15th postnatal day, as the muscle growth in control was rapid during this period. Though the rats rehabilitated after 10 days showed better recovery of muscle volume, complete restoration of the muscle volume was not achieved in any of the rehabilitated groups. Normal growth pattern of the nerve fibers and myelin of the sciatic nerve was also affected as a result of undernutrition. Both axonal and myelin growth was delayed resulting in more number of thin fibers (0-1.5 .mu.m) and reduced myelin thickness. Significant growth retardation persisted in the nerve fibers after rehabilitation. Myelin showed normal values in rats rehabilitated after 10 days of undernutrition while rats rehabilitated later showed a retarded myelin growth. No other structural alterations were evident in these tissues. The study demonstrated that the nutritional requirement for a timely growth of the tissues needs to be made available during the early postnatal period. The adequate recovery of the myelin in the rats rehabilitated as early as 10 days suggests that myelin growth is initiated later than the growth of the muscle and axons.