Effect of electroacupuncture on NF-κB and NLRP3 inflammasome in uterine tissues of rats with primary dysmenorrhea

Abstract

To observe the effect of electroacupuncture (EA) on nuclear factor kappa B (NF-κB) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome in uterine tissues of rats with primary dysmenorrhea (PD), thus to explore the possible mechanism of EA for PD. Fifty female Sprague-Dawley (SD) rats were randomly divided into a normal group, a model group, an EA at non-acupoint group, an EA at acupoint group and a Western medicine group, with 10 rats in each group. Except for the normal group, rats in the other four groups were treated with estradiol benzoate combined with oxytocin for 11 d to establish PD rat models. From day 1 of the modeling, rats in the normal group and the model group were only properly grasped without any intervention; Guanyuan (CV 4) and Sanyinjiao (SP 6) were selected for EA treatment in the EA at acupoint group; rats in the EA at non-acupoint group were treated with EA at 5 mm away from the acupoints selected above; rats in the Western medicine group were treated with ibuprofen via gavage. Rats in each group were treated for 10-day successively. On the 11th day, except for the normal group, rats in the other groups were intraperitoneally injected with oxytocin (2 U/rat), and the writhing number within 30 min in each group was compared; the pathological changes in rat uteruses were observed by hematoxylin-eosin (HE) staining, and the pathological damage scores were evaluated. Protein expression levels of NF-κB p65, phospho-NF-κB p65, NLRP3, cysteine aspastic acid-specific protease 1 (caspase-1), interleukin (IL)-1β and IL-18 were detected by Western blot. Compared with the normal group, the writhing number increased significantly (P 0.05) in the Western medicine group; compared with the Western medicine group, the phospho-NF-κB p65/NF-κB p65 ratio, also the NLRP3, IL-1β and IL-18 protein levels of the uterine tissues decreased significantly in the EA at acupoint group (all P 0.05); there were no significant differences between the EA at non-acupoint group and the model group in any indicators (all P>0.05). EA at acupoints significantly improves the pain and pathological damages of PD rats. The mechanism may be related to the reduced uterine inflammation via inhibiting NF-κB phosphorylation and NLRP3 activation in uteruses of PD rats.