Objective To observe the effect of acupuncture on the expression of proinflammatory cytokines interleukin-1β(IL-1β)

interleukin-6(IL-6)

microglia marker ion calcium adaptor protein(Iba-1) and triggering receptor expressed on myeloid cells 2(TREM2) in the prefrontal cortex of chronic stress-induced depression rats

so as to explore its antidepressant mechanism. Methods Thirty-two SD rats were randomly divided into normal control

model

acupuncture and fluoxetine groups

with 8 rats in each group. The depression model was established by using chronic mild unpredictable stress methods for 6 weeks. Manual acupuncture stimulation was applied to "Baihui"(GV20) and "Yintang"(GV29) for 10 min before modeling for 6 weeks. Fluoxetine(10 mg/kg

1 mg/mL) was given to rats of the fluoxetine group by gavage before stress stimulation

once every day for 6 weeks. The open field test was used to evaluate the behavioral changes of rats. The contents of IL-1β

IL-6 in the prefrontal cortex were determined by enzyme-linked immunosorbent assay(ELISA). Immunohistochemistry was used to determine the expression of Iba-1 in the prefrontal cortex. The TREM2 gene expression in the prefrontal cortex was determined by real time fluorescent quantitative polymerase chain reaction(RT-PCR). Results After modeling

the crossing numbers and rearing times were significantly decreased in the model group relevant to the control group(P<0.05). After the treatment

the crossing numbers were significantly increased in the acupuncture and fluoxetine groups(P<0.05)

while the rearing times in the acupuncture group were significantly increased(P<0.05). Compared with the control group

the contents of IL-1β

IL-6 and the expression of Iba-1 positive cells in the prefrontal cortex were significantly increased in the model group(P<0.05)

while the expression of TREM2 gene in the prefrontal cortex was significantly decreased(P<0.05). After the treatment

the increased levels of IL-1β

IL-6 and Iba-1 positive cells and the decreased TREM2 gene expression were considerably reversed in both acupuncture and fluoxetine groups compared with the model group(P<0.05). Conclusion Acupuncture intervention plays a positive role in anti-depression in rats

which may be related to its effects in inhibiting the activation of microglia

reducing the expression of proinflammatory cytokines

and increasing TREM2 expression in the prefrontal cortex.