OBJECTIVETo observe the expression change of mitophagy-related proteins in skeletal muscle in rats with spleen deficiency syndrome and to explain the partial action mechanism of acupuncture at Zusanli (ST 36) for spleen deficiency syndrome.

METHODSForty male SD rats, after normal feeding, were randomly divided into a normal group, a spleen deficiency group, a Zusanli group and a non-acupoint group, ten rats in each group. Except the normal group, the three factors modeling method was used for 14 days to establish the model of spleen deficiency syndrome on the other 3 groups. The rats in the Zusanli group were treated with EA at bilateral "Zusanli" (ST 36), while the rats in the non-acupoint group were treated with EA at bilateral non acupoint (dense-sparse wave, frequency of 2 Hz/100 Hz, 20 min per treatment, once a day for 10 days). The rats in the normal group and spleen deficiency group were treated with immobilization for 20 min per day, and no EA was given. The HPLC method was applied to measure the content of adenosine triphosphate (ATP) and adenosine monophosphate (AMP) in skeletal muscle. The Western blotting method was applied to measure the expression of adenosine monophosphate activated protein kinase (AMPK), p-AMPK, ULK1, p-ULK1，LC3-Ⅰand LC3-Ⅱ in skeletal muscle.

RESULTSThe ATP content in the spleen deficiency group was significantly lower than that in the normal group (<0.01); the ATP content in the Zusanli group was significantly higher than that in the spleen deficiency group (<0.05) but lower than that in the normal group (<0.05), there was no significant difference between the non-acupoint group and the spleen deficiency group (>0.05). Compared with the normal group, the AMP/ATP in the spleen deficiency group and the Zusanli group were significantly up-regulated (<0.01, <0.05). The differences of p-AMPK/AMPK between the spleen deficiency group and the normal group was not significant (>0.05). Compared with the normal group and spleen deficiency group, the p-AMPK/AMPK in the Zusanli group was significantly up-regulated (both <0.05). The p-ULK1/ULK1 and LC3-Ⅱ/LC3-Ⅰin the Zusanli group was higher than those in the normal group and spleen deficiency group (all <0.01).

CONCLUSIONEA at "Zusanli" (ST 36) might activate AMPK and produce stable ULK1/AMPK compound and increase the mitochondrial autophagy, which could regulate spleen-stomach and treat spleen deficiency.