The splenic sinuses

lymphocytes and antigen presenting cells in the spleen of rat stimulated by He-Ne laser acupuncture were observed by using TEM to investigate the ultrastructural changes of them.The width of endothelial interstice was increased

hence a lot of blood cells oozed out of the splenic sinuses. There were numerous activated T cells which contained abundant mitochondria and ribosome in the periarterial lymphatic sheaths. The B cells were gradually differentiated into large lymphocytes

immature and mature plasmatic cells with a lot of endoplasmic reticula. They were prominently increased in the splenic nodules. The macrophages had short processes with numerous folds and microvilli and tended to neighboring lymphocytes. The nucleus pores were increased. There were a lot of vacuoles

phagosome and mitochondria were closed to macrophages and lymphocytes. In conclusion the activities of the cellular immunity and humoral immunity were enhanced by laser