Acupoint application therapy alleviates pain by regulating immune function through inhibiting TLR4/MyD88/NF-κB p65 signaling in a primary dysmenorrhea rat model.

Abstract

To investigate the effects of graphene-based warm uterus acupoint paste on uterine Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear transcription factor-kappa B p65 (NF-κB p65) signaling pathway and Th1/Th2 immune balance in primary dysmenorrhea ( PD ) model rats, so as to reveal its immunological mechanisms of relieving dysmenorrhea. Thirty SD female rats were randomly divided into 3 groups：normal group, model group and acupoint paste group, with 10 rats in each group. PD rat model was established by subcutaneous injection of estradiol benzoate for 10 consecutive days. At the same time of modeling, graphene-based warm uterus acupoint paste was applied to the acupoints of "Guanyuan" (CV4), bilateral "Zigong" (EX-CA1) and "Sanyinjiao" (SP6) of rats in the acupoint paste group. The application was continuously applied once daily for 10 d, 5 h each time. On the 11th day, oxytocin was injected intraperitoneally to observe the writhing latency, writhing times within 30 min and writhing score of rats in each group. The spleen and thymus indexes were calculated. The pathological changes of spleen and thymus tissue were observed after HE staining. The contents of serum immunoglobulin (Ig) A, IgG, tumor necrosis factor-α (TNF-α), interleukin (IL)-2, interferon-γ (IFN-γ), IL-4 and IL-10 were detected by ELISA . The protein and mRNA expression levels of TLR4, MyD88 and NF-κB p65 in rat uterine tissue were detected by Western blot and real-time quantitative PCR, respectively. Compared with the normal group, the writhing times and writhing scores within 30 min of rats in the model group were significantly increased(P<0.001), and the rats showed writhing reaction (P<0.01). The spleen index and thymus index were significantly decreased(P<0.01, P<0.05). The spleen and thymus had obvious pathological changes. The contents of IgA, IgG, TNF-α, IL-2 and IFN-γ in serum were significantly increased, while the contents of serum IL-4 and IL-10 were significantly decreased(P<0.001, P<0.01). The expression levels of TLR4, MyD88, NF-κB p65 protein and corresponding mRNA in uterine tissue were significantly increased(P<0.001). Following intervention, compared with the model group, the writhing latency time of rats in the acupoint paste group was prolonged, and the writhing times and writhing scores within 30 min were significantly decreased (P<0.001). The spleen index and thymus index were significantly increased(P<0.01, P<0.05). The pathological changes of spleen and thymus were improved. The contents of serum IgA, IgG, TNF-α, IL-2 and IFN-γ were significantly decreased, while the contents of IL-4 and IL-10 were significantly increased(P<0.001, P<0.05, P<0.01). The expression of TLR4, MyD88, NF-κB p65 protein and the corresponding mRNA levels in uterine tissue were decreased(P<0.001, P<0.01). Graphene-based warm uterus acupoint paste can regulate the immune balance of Th1/ Th2 by regulating TLR4/ MyD88/ NF-κB p65 signaling pathway, repair the pathological damage of immune tissue, improve immune function, and effectively relieve the pain symptoms of PD rats.