A study was conducted to investigate the mobilization of murine immunocytes in the thymus, spleen, lymph nodes and blood during voluntary exercise training. Twelve six-week old inbred C57 BL/6 Cr mice used for the experiment were divided into two groups : sedentary controls (n=5), and mice taking voluntary exercise training (n=7) on running wheels. When the mice were 6 weeks at age, a 6 -week period of voluntary exercise training was started. Spleen weight was decreased in mice taking voluntary exercise training, but the weights of thymus and lymph nodes did not change significantly compared with the control group. The percentages of CD 4⁺ and CD 8⁺ immunocytes were increased in blood. The percentage of CD 8⁺ cells was increased in the spleen, but the percentage of CD 45 R/B 220 cells in the spleen was decreased significantly. The relationships between immunocytes in various organs and spleen weight were significant (CD 8⁺ in blood and spleen weight ; P <0.05, CD 8⁺ in thymus and spleen/BW ; PC0.05, CD 45 R/B 220 in spleen and spleen/BW ; P<0.05). The relationships between immunocytes in various organs were correlated with CD 4⁺ cells in blood and CD 4⁺ cells in lymph nodes (r = -0.816 ; P<0.05). These results suggest that the percentages of immunocytes in mice during voluntary exercise training vary among different organs.

DESCENTE SPORTS SCIENCE Vol.17/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE