Pretreatment With Berberine Protects Against Lipopolysaccharide-induced Intestine Injury In An α₂-adrenoceptor-independent Manner In Mice

ObjectiveBerberine (Ber) has been demonstrated to protect against intestinal injury induced by lipopolysaccharide (LPS) and activateα2-adrenoceptor. However, it is unknown whetherα2-adrenoceptor activation is involved in protection of Ber against LPS-induced gut damage. The aim of the present study was to investigate the mechanisms responsible for preventing intestinal damage by oral Ber and the role ofα2-adrenoceptor activation in the action of Ber in endotoxemia mice.MethodsMale BALB/c mice were randomly divided into 8 groups:control, LPS, Ber+LPS, Ber+yohimbine(Y, an a2.adrenoceptor antagonist)+LPS, Y+LPS, Ber, Ber+Y and Y. Mice were administered intragastrically with distilled water (0.1 mL/10 g), Ber (50 mg/kg), Ber (50 mg/kg) in combination with Y(2 mg/kg) or Y (2 mg/kg) once a day for 3 days. One hour after intragastrical treatment on the third day, LPS (18 mg/kg) or normal saline was injected intraperitoneally. The histological changes of intestine were observed, and injury score was assessed. The mucosal weight, villus height and the content of plasma D-lactate, diamine oxidase (DAO) in plasma and ileum, macrophage inflammatory protein (MIP-2) expression were also measured. FITC-dextran was used as a probe to detect the intestine permeability.Enterocyte proliferation was identified by immunohistochemical staining for proliferating cell nuclear antigen (PCNA) and apoptotic enterocytes were analyzed by TUNEL. Furthermore, myeloperoxidase (MPO) activity was determined in a spectrophotometric method and the content of MPO, cleaved caspase-3 was estimated by western-blotting. ResultsCompared to the control mice, the mice challenged with LPS showed intestinal injury, including significantly increased injury score, decreased gut mucosa weight, villus height, DAO content in ileum and increased FITC-dextran permeability. Furthermore, enterocyte proliferation was inhibited significantly and enterocyte apoptosis was remarkably enhanced according to the increased apoptosis index and cleaved caspase-3 expression after LPS challenge. Additionally, activity and content of MPO, MIP-2 expression were increased. Pretreatment with Ber and Ber+Y significantly inhibited intestinal injury, attenuated enterocyte proliferation impairment, alleviated enterocyte apoptosis and inhibited LPS-induced an increase in MPO activity and content, cleaved caspase-3 and MIP-2 expression in the ileum. However, no significantly difference in the above parameters between Ber+LPS and Ber+Y+LPS groups. Treatment with Y only did not prevent LPS-induced intestinal injury.ConclusionPretreatment with berberine remarkably inhibits LPS-induced intestinal injury via reducing enterocyte proliferation impairment, apoptosis, MIP-2 expression and neutrophil migration in an alpha 2 adrenoceptor-independent manner.