Abstract: Objective To observe the changes in the abundance of Lactobacillus reuteri in ovariectomy model rats under the intervention of electroacupuncture, and to explore the possible mechanism of acupuncture in preventing and treating postmenopausal osteoporosis from the perspective of the involvement of Lactobacillus reuteri in regulating bone health. Methods Thirty 3-month-old female SD clean rats were selected and randomly divided into 5 groups, which were blank group, sham-operation group, model group, fixation group, and electroacupuncture group, with 6 rats in each group. The rats in model group, fixation group, and electroacupuncture group received bilateral ovary removal. Fixation group was fed with antibiotics for two weeks, and then Lactobacillus reuteri was added in sterile water and fed for three times per week. Electroacupuncture group received electroacupuncture at the following acupoints: (1) Guanyuan(CV4) + Sanyinjiao(SP6); (2) Shenshu(BL23) + Housanli(ST36), and the acupoints of the two groups were alternated, and electroacupuncture stimulation was performed for 20 min each time, once a day, 5 d per week for a total of 12 weeks. Blank group, sham-operation group and model group only received routine rearing without any special treatments. After 12 weeks, the rats were put to death, and the bone mineral densities (BMDs) of right tibia and femur were determined uniformly by bone densitometer, and the serum levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 were detected by enzyme linked immunosorbent assay (ELISA).The expression of receptor activator of nuclear factor-κB ligand (RANKL) protein in bone homogenate was detected by Western blot, and the structural changes of intestinal flora in the feces of rats were detected by real time quantative polymerase chain reaction. Results Compared with the model group, the BMDs of tibia and femur were significantly increased (P<0.05), the levels of TNF-α, IL-6 and RANKL protein were significantly decreased, and the abundance of Lactobacillus reuteri showed a significant enrichment (P<0.05) in the colonization group and the electroacupuncture group. Conclusions Electroacupuncture intervention can increase the BMD of ovariectomy model rats, down-regulate the expression levels of serum TNF-α, IL-6 and RANKL proteins, and regulate the abundance of Lactobacillus reuteri in the intestinal tract of ovariectomy model rats.

Key words: postmenopausal osteoporosis, bone mineral density, inflammatory factor, Lactobacillus reuteri