Original articles
DONG Ji, YAO Chuan-fu, XIAO Yi, WANG Hui, WANG Hao-yu, ZHANG Jing, XU Xin-ping, YAO Bin-wei, ZHOU Hong-mei, ZHAO Li, PENG Rui-yun
Objective To investigate the effects of long-term exposure to multi-frequency microwaves of S band and X band on the immune function of rats. Methods Ninety-six male Wistar rats were randomly divided into four groups： the sham radiation group （Sham）,S-band microwave radiation group （S10）,X-band microwave radiation group （X10） and compound radiation group （SX10）. The S-band and X-band microwaves at an average power density of 10 mW/cm2 were used for 6 min,1 time/d,and 30 d of continuous radiation,respectively,and the compound group was radiated by S-band microwaves before X-band microwaves. At 6 h,7 d,14 d and 28 d after radiation,peripheral blood cells were analyzed by blood counters. The serum immunoglobulins （IgA,IgM and IgG） and complement （C3 and C4） were detected by ELISA. The concentrations of cytokines （IL-2,IL-4,IL-10,IL-12p70,IL-13,IL-17A,TNF-α and IFN-γ） were detected by the multifunctional liquid chromatography platform. Hematoxylin eosin staining and light microscopy were used to observe the tissue structure of the spleen and thymus. Transmission electron microscopy was used to observe the ultrastructure of the spleen and thymus. Results Compared to the sham group,the number of leukocytes and lymphocytes in the peripheral blood of the SX10 group was decreased significantly at 6 h （P< 0.01 or P< 0.001） and was recovered at 7 d and 14 d after radiation,but there was no significant change in the S10 or X10 groups. The concentrations of IgM and complement C3,C4 in serum were decreased significantly at 6 h （P< 0.05 or P< 0.01） but recovered at 7 d or 14 d after radiation in the SX10 group. The concentrations of IL-2,IL-4,IL-10,IL-12p70,IL-13 and TNF-α were significantly increased in the SX10 group at 6 h （P< 0.05,P< 0.001） but recovered at 7 d after radiation. The nuclei of lymphocytes in the thymus and spleen tissues of rats in each radiation group were fragmented at 6 h and 7 d after radiation before being recovered at 28 d after radiation. At 7 d after radiation,mitochondrial vacuolation and cristae breakage were observed in lymphocytes of thymus and spleen tissues of each radiation group,and lysosomes were seen in X10 and SX10 groups. Conclusion Long-term compound exposure to 10 mW/cm2 S-and X-band microwaves can result in suppression of peripheral blood cells,immunoglobulins and complements,with damage to the structure of the thymus and spleen.
