Effect of electroacupuncture on intestinal calcium absorption and expression of transmembrane calcium transport-related receptors in ovariectomized rats / 针刺研究

ABSTRACT

OBJECTIVE: To observe the effect of electroacupuncture (EA) on bone mineral density (BMD) and expression of calcium transport-related receptors in ovariectomized rats, so as to explore its mechanisms underlying improvement of osteoporosis. METHODS: Thirty-two three-month female SD rats were randomly divided into control, sham operation, model and EA groups (n=8 in each group). The ovariectomy model was established by resection of bilateral ovaries. EA (2 Hz/15 Hz, 2 mA) was applied to "Guanyuan"(CV4)+"Sanyinjiao"(SP6) or "Shenshu"(BL23)+"Housanli"(ST36) alternatively for 20 min, once daily (except the weekends) for 12 weeks. BMD of the tibia and femur were detected by using a bone densitometer. The expression levels of transient receptor potential vanillic receptor 5 (TRPV5), transient receptor potential vanillic receptor 6 (TRPV6), sodium calcium exchanger 1 (NCX1), membrane calcium adenosine triphosphate hydrolase (PMCA1b), zonula occludens 1 (ZO-1), occludin and claudin in intestinal mucosa were detected by quantitative real-time PCR and Western blot, respectively. RESULTS: Following modeling, BMD of both tibia and femur, and expression levels of TRPV5, PMCA1b, ZO-1, occludin and claudin mRNAs were significantly decreased in the model group compared with the control and sham operation groups (P<0.05, P<0.01)，while the mRNAs levels of TRPV6 and NCX1 in the model group were increased (P<0.01). After the treatment, BMD of both tibia and femur, and expression levels of TRPV5, PMCA1b, ZO-1 and occludin mRNAs were significantly increased(P<0.01，P<0.05)，and TRPV6 and NCX1 were significantly decreased(P<0.01，P<0.05) in the EA group than those in the model group. Compared with the control and sham operation groups, protein expression levels of TRPV5, PMCA1b, ZO-1, occludin and claudin in the model group were significantly decreased (P<0.05), while the protein levels of TRPV6 and NCX1 in the model group were increased (P<0.05). After EA intervention, modeling-induced decrease of TRPV5, PMCA1b, ZO-1, occludin and claudin protein levels and increase of TRPV6 and NCX1 protein levels were all completely reversed in the EA group relevant to the model group (P<0.05). CONCLUSION: EA intervention can improve bone mineral density and up-regulate the mRNA and protein expression of TRPV5, PMCA1b, ZO-1 and occludin, which may be one of the mechanisms of acupuncture in the treatment of osteoporosis.