[Effects of Acupuncture Intervention on Levels of T Lymphocyte Subsets in Plasma and Thymus in Stress-induced Anxiety Rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) intervention on the levels of CD 4+ and CD 8+ lymphocytes in the plasma and thymus in anxiety disorder rats, so as to explore its mechanism underlying favorable regulation of immune function.
METHODS: Thirty-four SD rats were randomly divided into control (n = 10) , model (n = 12) and EA (n = 12) groups. The anxiety model was established by using chronic unpredictable emotional stress stimulation (fasting, water-deprivation, shaking, tail-clamping, forced warm- and cool-water swimming, electrical shock stimulation, etc.) for 15 days. EA (15 Hz/ 25 Hz) was applied to "Neiguan" (PC 6) and "Shenmen" (HT 7) for 15 min, once every other day for 15 days. The anxiety-like behavior was measured by elevated plus maze test. Anxiety reduction in the plus-maze is indicated by an increase in the proportion of time spent in the open arms (time in open arms/total time in open or closed arms) , and an increase in the proportion of entries into the open arms (entries into open arms/total entries into open or closed arms). While the contents and expression of CD 4+ and CD 8+ in the plasma and thymus tissues were measured by ELISA and immunohistochemistry, respectively.
RESULTS: The values of proportions of open-arm entries (OE%) and the content of plasma CD 4+ lymphocytes were obviously lower in the model group than in the control group (P < 0.05), and were significantly higher in the EA group than in the model group (P < 0.05). Whereas, the content of plasma CD 8+ lymphocytes was obviously higher in the model group than in the control group (P < 0.05) and markedly down-regulated in the EA group after the treatment (P < 0.05). The ratio of CD 4+/CD 8+ was decreased in the model group in comparison with the control group (P = 0.054), and was significantly up-regulated in the EA group after EA stimulation (P < 0.01). Compared with the control group, the expression levels (optical density, OD values) of CD 4+ and CD 8+ lymphocytes in the thymus tissue were obviously decreased in the model group (P < 0.01). After EA, the expression levels of thymus CD 4+ and CD 8+ were remarkably up-regulated in the EA group (P < 0.05). No significant changes were found in proportion of open-arm time (OT%, P > 0.05).
CONCLUSION: EA can effectively relieve anxiety disorder in anxiety rats, which may be related to its effects in up-regulating plasma CD 4+ , thymus CD 4+ and CD 8' levels as well as CD 4+/CD 8+ ratio, and down-regulating plasma CD 8+ content.