RESUMEN
OBJECTIVE@#To investigate whether collagen peptides can improve the immune functions of mice under the condition of simulated weightlessness.@*METHODS@#Mouse tail-suspension model was used to simulate the effects of weightlessness. Tail-suspended mice were intraperitoneally injected with 600 mg collagen peptides per kilogram body weight once a day for 10 days. Then, the mice were killed, and white blood cells were counted and classified. Lymphocyte subsets and T lymphocyte proliferations in spleens were analyzed.@*RESULTS@#Compared with normal control group, total and differential count of leukocytes, lymphocytes, T cells，CD4 and CD8 T cells, B cells and NK cells, and splenic T lymphocyte proliferation all decreased in the weightlessness simulated mice (P＜0.05). Except for NK cells, the above-mentioned parameters were increased after administration of collagen peptides, and some of the parameters were recovered to the levels of normal control mice (P＜0.05).@*CONCLUSION@#Collagen peptides can effectively improve peripheral blood lymphocyte distributions and T lymphocyte proliferations of mice under the condition of simulated weightlessness. This study nay provid the experimental basis for improvement of immune functions of astronauts.