Protective effects of Dendrobium officinale superfine powder against LPS-induced intestinal mucosal injury in mice / 中国中药杂志

ABSTRACT

This study aims to investigate the preventive effect of Dendrobium officinale in LPS-induced intestinal mucosal damage. Forty SPF-grade C57 BL/6 J male mice were randomly divided into normal group(NC), model group(LPS), and two superfine powder groups of Dendrobium officinale(DOF)(DOF-L, 0.30 g·kg~(-1)and DOF-H, 0.60 g·kg~(-1), respectively), with 10 mice in each group. DOF superfine powder suspension was given via oral administration to mice for 7 days, while the mice in NC and LPS groups received the same volume of saline for 7 days. On the eighth day, the mice in LPS group and DOF treatment groups were injected with LPS(5 mg·kg~(-1)) by intraperitoneal injection to establish the intestinal mucosal injury model, while the mice in NC group were injected with the same volume of sterile saline in the same manner. Six hours after injection with LPS or saline, plasma and the intestinal tissue were collected. The diamine oxidase(DAO) and D-lactate levels in plasma were detected with a biochemical method. The levels of proinflammatory factors interleukin-6(IL-6) and tumor necrosis factor-α(TNF-α) in plasma were detected by ELISA. The histomorphology and ultrastructure of mouse ileum tissues were observed by hematoxylin-eosin(HE) staining in optical microscope and transmission electron microscope(TEM). The expression and distribution of tight junction(TJ) proteins claudin-1, occludin and F4/80 were detected by immunohistochemistry while the protein expression levels of Toll-like receptor 4(TLR-4) and nuclear factor kappa B p65(NF-κB p65) in jejunum were detected by Western blot. The experimental results showed that continuous intragastric administration of D. officinale superfine powder for 7 days obviously alleviated the damage and ultrastructural changes of intestinal mucosa induced by LPS; significantly decreased DAO and D-lactate levels in plasma in model group(P<0.05); up-regulated the protein expression of claudin-1 and occludin in ileum tissues; down-regulated the protein expression of TLR-4 and NF-κB p65 in jejunum tissues(P<0.01); significantly decreased TNF-α and IL-6 levels in plasma(P<0.05); and decreased the infiltration of F4/80~+ macrophage cells. Our results suggested that D. officinale had significant protective effects on LPS-induced intestinal mucosal damage and reduced intestinal permeability. The mechanism might be related to its effects of inhibiting inflammation via TLR-4/NF-κB p65, and up-regulating the expression of tight junction proteins.