ABSTRACT
ObjectiveTo investigate the mechanism of Akkermansia muciniphila （A. muciniphila） regulating the visceral hypersensitivity in irritable bowel syndrome （IBS） rats induced by neonatal maternal separation （MS） and water avoidance stress （WAS）. MethodsNeonatal male Sprague-Dawley rats were randomly divided into sham WAS group （blank group）， MS+WAS group （IBS model group） and A. muciniphila group. IBS model was established by MS combined with WAS in both IBS model group and A. muciniphila group. Meanwhile， the rats in the A. muciniphila group were given 1 mL 1×109 CFU/mL A. muciniphila by gavage daily for 10 days. Visceral pain responses were detected by behavioral observations and abdominal withdrawal reflex scores. ResultsCompared with IBS model group， A. muciniphila group exhibited significant increase of body weight and visceral pain threshold， significantly decreased numbers of fecal particles and proportions of unformed stools， significantly higher expression levels of cannabinoid receptor type 2 （CB2R） mRNA in colon tissues. ConclusionA. muciniphila may alleviate the visceral hypersensitivity in IBS rats by regulating the expression of CB2R mRNA in colonic tissues.
ABSTRACT
Cannabinoid receptor type 2( CB2 R),a member of the G protein-coupled receptor( GPCR) superfamily,has a variety of biological activities,such as regulating pain response,resisting inflammation and fibrosis,and mediating bone metabolism. Some CB2 R regulators exhibit a good regulatory effect on bone metabolism. Cannabinoids in Cannabis sativa can cause psychoactive effects despite various pharmacological actions they exerted by targeting CB2 R. Therefore,it is of great significance to discover CB2 R regulators in non-Cannabis plants for finding new lead compounds without psychoactive effects and elucidating the action mechanism of plant drugs. The present study clarifies the discovery,structure,and physiological functions of CB2 R,especially its regulatory effects on bone metabolism,summarized CB2 R regulators extracted from non-Cannabis plants,and systematically analyzes the regulatory effects of CB2 R regulators on bone metabolism in animals,osteoblasts,and osteoclasts,to provide a scientific basis for the discovery of new CB2 R regulators and the development of anti-osteoporotic drugs.