Study To Bovine Endometrial Tissue α7-nAChRs Mediated Anti-inflammatory Effects And Mechanism

Dairy cow has energy negative balance situation and major mineral ions of body fluid in lower level during postpartum.The pathogenic bacteria infect endometrium caused endometritis when the uterus was changed in anatomy,physiology and immune status.Bovine endometritis is the most common postpartum disease associated with infertility and subfertility,which leads to serious economic losses to restrict development for the dairy industry in China.It has no uniform and reliably science project to treat and prevent bovine endometritis so far.The antibiotic and hormone are most common to treat bovine endometritis,but as resistance bacteria increased and antibiotic residues influence human healthy,and hormone disorder estrous cycle.Hence,it is important to exploit new drug to treat bovine endometritis.The cholinergic anti-inflammatory pathway(CAP)provides new thought to treat inflammation disease.Alpha-7 nicotine acetylcholine receptors(α7-nAChRs)play a central role in CAP,which is a potential drug target to treat inflammation diseases.However,there has been still no report about endometritis treated by α7-nAChRs.The study aimed to clarify the effect and underlying anti-inflammatory mechanism ofα7-nAChRs in LPS-induced bovine endometritis.The results showed that IL-6 mRNA expression in peak value when LPS treated 12 hours in bovine endometrium,so the study chose 12 hours as LPS stimulation time.The results of immunofluorescence showed that α7-nAChRs was expressed in bovine endometrial tissues,andα-nAChRs expression was decreased when treated LPS.The results showed that the mRNA expression of IL-1β,IL-6,IL-8,and TNF-α in LPS-treated for 8 hours and 12 hours were significantly increased in bovine endometrial tissue compare with control group.α7-nAChRs agonist PNU-282987 in concentration 5 μmol/L,10 μmol/L,15μmol/L inhibited IL-1β,IL-6,IL-8,and TNF-α mRNA expression,while α7-nAChRs antagonist MLA reversed the effective of agonist.Pathological histology results showed that LPS induced part of endometrial epithelial cell shed,and the structure of endometrial gland was destroyed.Alpha7-nAChRs agonist PNU-282987 in concentration 5,10,15 μmol/L can protect the damage of endometrial tissue in different extent,while α7-nAChRs antagonist MLA counteract the effective of agonist.Western blotting results showed that LPS induced phosphorylation of JAK2 and STAT3,the P-JAK2 and P-STAT3 were inhibited when α7-nAChRs activation,and the effective was inhibited by ML A.LPS increased COX-2 and mPGES-1 mRNA and protein expression and PGE2 secretion,α7-nAChRs agonist markedly decreased mPGES-1 mRNA and protein expression and PGE2 generation,while MLA counteract the effective.In COX-2 inhibitor test,COX-2 inhibitor NS398 and CAY10404 significantly decreased COX-2 expression and PGE2 generation,but COX-2 expression and PGE2 generation were markedly increased when activationα7-nAChRs.The results demonstrated that α7-nAChRs can inhibit pro-inflammatory expression and protect damage in bovine endometrial tissue.The activation of α7-nAChRs via JAK2/STAT3 signaling pathway and PGE2(derived from COX-2)inhibited inflammation of bovine endometrial tissue.Therefore,α7-nAChRs can as potential drug target to prevent and treat bovine endometritis.