Immunostimulatory effects of arginine in normal and injured rats

We have shown in the present experiments that femoral fractures, particularly bilateral fractures, lead to impaired thymic function in rats as assessed by thymic size, numbers of thymic lymphocytes, and ability of thymic lymphocytes to respond to mitogenic stimulation. The in vitro depression in T-cell function appears to be a primary one since it is also observed in serum-free microculture systems. We have also shown that 1% dietary arginine supplementation largely prevents or minimizes the thymolysis and T-cell dysfunction that appear post-trauma. In addition, dietary supplemental arginine significantly increases thymic weight, cellularity, and T-cell blastogenic responsiveness in uninjured rats. This suggests that arginine may be a safe nutritional means of correcting immune depression in injured and/or stressed patients.