Effect of Amino Acid L - leucine On the Musculo - Skeletal Changes during Cast - Immobilization in Adult Male Albino Rats . Physiological and Histological study

The relation between muscle atrophy and bone osteoporotic changes due to immobilization are still not completely understood. This study tried to throw more light on this association and to probe the ability of amino acid Lleucine, to limit these changes in a trial to accelerate rehabilitation. Adult male Albino rats weighing 180-210 g were used and classified into three groups, I-control group, II-cast-immobilized group and III-immobilized-L-leucine treated group. Right hind-limb cast immobilization was performed for 15 days in groups II&III, while L-leucine, was given by oral gavage in a dose 0.7g/kg/day concomitant with immobilization in group III. The initial and final body weights were determined. Blood samples were used for determination of serum levels of total calcium, CPK, ADH, TNFα and Cortisol as well as for plasma MDA and glucose level. In the immobilized right hind-limb after removing the cast, the gastrocnemius muscle was identified, dissected, weighed. Then the right gastrocnemius muscle was prepared for light and transmission electron microscopic studies and the right tibia was prepared for both decalcified and un-decalcified light microscopic studies. Cast-immobilized group II showed significantly increased serum calcium, LDH, CPK, cortisol, TNFα and plasma MDA with non-significant change in blood glucose level. Also immobilization resulted in significantly reduced body weight, reduced gastrocnemius body weight ratio and resulted microscopically in both skeletal muscle atrophy in the gastrocnemius muscle and osteoporosis in the tibia cancellous bone compared with control group. Immobilized -Leucine treated group-III exhibited significantly reduced LDH, CPK, MDA and glucose levels but the levels of calcium was non-significantly altered compared to immobilized non treated group. Although serum cortisol and TNFα levels in leucine treated group were reduced non-significantly compared to immobilized non treated group, microscopically Leucine administration to cast-immobilized rats of group III markedly prevented skeletal muscle atrophy and partially prevented cancellous bone osteoporosis. It is concluded that increased MDA, Cortisol, TNFα with immobilization may explain in part the associated changes in muscle and bone. Leucine prevented these changes which could be attributed to its direct anabolic effect or its ability to reduce oxidative stress and /or its ability to counteract the effect of Cortisol and TNFα rather than reducing their levels. Overall, these data suggesting that leucine intake may represent a nutritional strategy for limiting muscle and bone protein loss as a consequence of immobilization. [Bataa, M.A.EL-Kafoury, Nagwa Kostandy Kalleny and Ghada Galal Hamam. Effect of Amino Acid L-leucine On the Musculo-Skeletal Changes during Cast-Immobilization in Adult Male Albino Rats. Physiological and Histological study. Life Science Journal,. 2011; 8(2):776-892] (ISSN: 1097-8135). http://www.lifesciencesite.com.