Acupuncture ameliorates depression-like behavior of poststroke depression model rats through the regulation of gut microbiota and NLRP3 inflammasome in the colon

This study was conducted to examine the effects of acupuncture on gut microbiota and expression of NLRP3 inflammasome in the colon in poststroke depression (PSD) model rats. Sprague-Dawley male rats were randomized into four groups: sham surgery group, poststroke depression group, acupuncture group, and probiotics group. Acupuncture therapy at Baihui (GV20), Shenting (GV24), bilateral Zusanli (ST36) acupoints in the acupuncture group and probiotic gavage therapy in the probiotics group were performed once per day for 2 weeks. Behaviors of depression were assessed by using weight measurements, sucrose preference test, open field test, and forced swimming test. Histopathological alterations in the colon were determined by hematoxylin-eosin staining, the expression of NLRP3/ASC/caspase-1 pathway-related proteins was analyzed by western blotting. Serum levels of IL-1β and IL-18 were derived from ELISA. The 16S rRNA gene sequencing was performed to examine and analyze the differences of gut microbiota of rats among all groups. Acupuncture was effective to increase weight and ameliorate depressive-like behaviors in PSD rats. Acupuncture increased the diversity of gut microbiota, upregulated the abundance of Bifidobacteriaceae and Lactobacillaceae, and decreased the relative abundance of Peptostreptococcaceae, Rikenellaceae, Eggerthellaceae, and Streptococcaceae at family level. Acupuncture effectively improved the pathological changes in the colon. Meanwhile, acupuncture reduced NLRP3, ASC, caspase-1 protein expressions in the colon, and serum levels of IL-18 and IL-1β. Acupuncture may reduce depressive-like behaviors of PSD by regulating the gut microbiota and suppressing hyperactivation of NLRP3 inflammasome in the colon. Microbiota-gut-brain axis may be an effective target pathway for acupuncture treatment of PSD.