Protective Effect of Ginsenosides Rg1 and Rb1 Against Intestinal Epithelial Barrier Injury Induced by Lipopolysaccharide in Vitro / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate the effects of ginsenoside Rg1 and ginsenoside Rb1 on the release of inflammatory factors of human myeloid leukemia monocytes （THP-1） induced by lipopolysaccharide （LPS） and their protective effects on the inflammatory injury of intestinal epithelial cells （Caco-2） induced by THP-1 cell activation based on the co-culture system of THP-1 and Caco-2. MethodFirstly，the microfluidic chip of co-culture of THP-1 and Caco-2 cells was prepared. In the experiment， a blank group， an LPS group， and drug intervention groups were set up.The cells in the blank group were cultured conventionally. In the LPS group，LPS （1 mg·L-1） was added to the lower THP-1 cells after the upper Caco-2 cells formed a monolayer barrier. On the basis of the LPS group， 33 mg·L-1 ginsenoside Rg1 and 33 mg·L-1 ginsenoside Rb1 were added to THP-1 cells respectively. After the co-culture of THP-1 cells and Caco-2 cells for 24 hours， the fluorescein isothiocyanate （FITC）-Dextran fluorescence value in the lower chip channel was detected by FITC-Dextran tracer method. A blank group， an LPS group，and drug intervention groups were set up in the THP-1 cell experiment. THP-1 cells in the blank group were cultured conventionally. In the LPS group， LPS （1 mg·L-1） was added to THP-1 cells.Ginsenoside Rg1 and ginsenoside Rb1 of the corresponding doses （11，33，100 mg·L-1） were added to the drug intervention groups respectively on the basis of the LSP group. After 24 hours of cell culture， the activity of THP-1 cells was detected by cell counting kit-8 （CCK-8）. Real-time quantitative polymerase chain reaction （Real-time PCR） was used to detect the expression of inflammatory cytokines such as interleukin-6 （IL-6）， interleukin-1β （IL-1β）， and tumor necrosis factor （TNF）-α of THP-1 cells. A blank group， an LPS group， and drug intervention groups were set up in the Caco-2 cell experiment. Caco-2 cells in the blank group were cultured conventionally， and in other groups， the corresponding cell supernatant in the second part of the THP-1 cell experiment was employed in Caco-2 cells. After 24 hours of cell culture，the activity of Caco-2 cells was detected by CCK-8. Real-time PCR was used to detect the expression of IL-6，interleukin-8 （IL-8）， TNF-α， and Occludin of Caco-2 cells. The expression of tight junction protein Occludin in Caco-2 cells was detected by Western blot. ResultBoth ginsenoside Rg1 and ginsenoside Rb1 could effectively protect LPS-induced intestinal epithelial barrier permeability in the co-culture system of THP-1 and Caco-2 cells （P<0.01）. Ginsenosides Rg1 and Rb1 antagonized LPS-induced increased expression of IL-6，IL-1β， and TNF-α in THP-1 cells （P<0.05）. When the supernatant of THP-1 cells treated with ginsenosides Rg1 and Rb1 was co-cultured with Caco-2 cells， the expression of IL-6，IL-8， and TNF-α in Caco-2 cells was significantly reduced （P<0.01）， and the expression of tight junction protein Occludin was up-regulated. ConclusionIn the co-culture system of THP-1 and Caco-2 cells simulating the intestinal epithelial barrier function in vitro，ginsenosides Rg1 and Rb1 play a protective role against LPS-induced intestinal epithelial barrier injury by regulating the release of inflammatory cytokines by THP-1 cells， thereby regulating the inflammatory response and cell barrier integrity of Caco-2 cells.