Mesona chinensis Benth polysaccharide improves intestinal barrier function in dextran sodium sulfate-induced human Caco-2 cells and its molecular mechanisms

Mesona chinensis Benth is a traditional medicinal and edible plant commonly used in China. Previous studies have found that Mesona chinensis Benth polysaccharide (MBP) can exhibit anti-inflammatory and antioxidant activities, also alleviate colitis development in mice. To further investigate the effects of MBP on intestinal cell and intestinal barrier, dextran sodium sulfate (DSS)-induced inflammation models in Caco-2 cells were constructed. Our investigation results showed that DSS induced strong cytotoxicity on Caco-2 cells, while MBP intervention enhanced cell viability and alleviated cell damage through inhibiting lactate dehydrogenase (LDH) production. Moreover, DSS induced a dysregulated oxidative stress state, which can be ameliorated by MBP intervention through enhancing superoxide dismutase (SOD) activity, decreasing reactive oxygen species (ROS) content and reducing the secretion of inflammatory factors such as tumour necrosis factor-α (TNF-α) and interleukin 6 (IL-6), as well as decreasing the expression of cyclooxygenase (COX-2) protein. Additionally, MBP can ameliorate cell cycle arrest and attenuate apoptosis which was caused by DSS via the Caspase-3/Bcl-2/Bax pathway. Furthermore, MBP intervention could maintain the integrity and stability of Caco-2 monolayer cell, which was indicated by fall of fluorescent yellow permeability, rise of trans-epithelial electrical resistance (TEER) value and expression content of tight junction proteins (TJs) such as ZO-1, Occludin, and Claudin. These findings suggested that MBP may be developed as an intestinal protective agent, which will expand the application range and value of Mesona chinensis Benth.