Li Shaoyuan, Guo Xiao, Zhang Jinling, Li Liang, Rong Peijing*

(Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China)

Abstract：Objective: Depression is a common and multiple recrudescent psychiatric disorder. Our previous studies indicated that electric acupuncture at auricular could significantly decrease the high level score of 17 Hamilton Depression Scale. In this study, chronic unpredictable mild stimulation for 21 days was applied to make  depression  model.  We’d  like  to  explore  the  mechanism  of  auricular  electric  acupuncture  on  the expression of brain derived neural factor, cell proliferation and apoptosis in hippocampus. Method: 30 SD rats were divided into control (n=10), model (n=10) and auricular electric acupuncture (n=10) group. Except control group, rats in other groups should be under the CUMS for consecutive 21 days to make depression model, including fasting food and water, ice water swimming, tail clip, day and night inversion, wet packing and hot plate. The electric acupuncture is on the auricular conchea with 20 Hz and 2 mA 30 min per day for 28  days.  Hippocampus  of  all  animals  were  collected  by  the  end  of  the  experiments.  Western  blot  and immunohistochemistry were used to explore the expression of BDNF and cell proliferation and apoptosis in hippocampus respectively. Results: Compared with control group, the expression of BDNF in hippocampus of model rats decrease significantly (P<0.01) and electric acupuncture can inverse it obviously (P<0.01); the number  of  proliferation  cell  is  more  than  that  in  control  group  (P<0.01)  and  there  was  no  significant difference between electric acupuncture group and control group(P>0.05). The positive cells of apoptosis in hippocampus are less than control group but electric acupuncture can inhibit the decline of the apoptosis cell(P<0.01).  Conclusion:  Auricular  electric acupuncture  can up-regulate  the  expression  of BDNF and improve the condition of cell proliferation and apoptosis in hippocampus.

Key words: depression, auricular electric acupuncture, hippocampus, proliferation, apoptosis