| Lactic acid bacteria exopolysaccharides (LAB EPS) produced by lactic acid bacteria is the water solubility exopolysaccharides, existed generally in the leavened food, like in the yogurt and the cheese, and riched in biological activity, such as anti-tumor activity, immunomodulatory activity and regulation of gastrointestinal function and non-toxic side effects, therefore, by the widespread research and application. Currently, more research is on the physical and chemical properties and physiological functions of LAB EPS, but less in-depth study of the molecular and cellular level, also it is little known about immunomodulatory effects of EPS on peritoneal macrophages and intestinal tract macrophages. Macrophages play an important role in the inflammatory response, which produce a variety of cytokines and inflammatory mediators that are the internal mechanism of the inflammatory response, development, coordination and dissipate. In this study we investigated the effect of EPS on proliferation, phagocytosis and secretion of peritoneal macrophages and immunoregulation of intestinal tract macrophages.This study was mainly conducted in the following aspects:(1) Separate mouse peritoneal macrophages and intestinal tract macrophages by intraperitoneal injection and minor adjustments in accordance with the Frangakis method.(2) MTT assay was used to determine the proliferation of J774A.1cells and mouse peritoneal macrophages treated with EPS.(3) The morphologic feature of J774A.1cells and mouse peritoneal macrophages treated with EPS were photographed using an inverted phase microscop.(4) ELISA reader detected the effect of EPS on phagocytosis of J774A.1cells and mouse peritoneal macrophages.(5) Sandwich enzyme-linked immunosorbent assay methods determined the effect of EPS on secretion of mouse peritoneal macrophages and intestinal tract macrophages.(6) ELISA reader detected the effect of EPS on phagocytosis neutral red and production NO of intestinal tract macrophagesResults were showed as follows:(1) EPS could significantly promote the proliferation of J774A.1cells (P<0.05) and the proliferation ratio of J774A.1cells was197%±7.9at the concentration of the EPS400μg/mL,48h. EPS could suppress LPS-induced inhibition of J774A.1cells growth status and the proliferation ratio of J774A.1cells treated with LPS was185%±9.7at the concentration of the EPS450μg/mL,48h. EPS had no effect on proliferation of primary peritoneal macrophages which are limited cell lines different from unlimited cell lines such as J774A.1cells. LPS could slightly reduce the number of primary peritoneal macrophages and EPS could restore LPS-induced the reduction in the number of cells. EPS could be an inhibitor of LPS. (2) EPS could promote the proliferation of J774A.1cells and not change in J774A.1cells morphology. EPS was not cytotoxic effect on cells. The cell morphology was obviously changed by LPS. EPS could decrease the LPS-induced morphological changes.(3) EPS could significantly promote the phagocytosis of J774A.1cells and peritoneal macrophages (P<0.05) and the best concentration of the EPS was400μg/mL. EPS could significantly suppress LPS-induced phagocytosis of J774A.1cells and peritoneal macrophages (P<0.05).(4) EPS could significantly promote the TNF-α, IL-1β and IL-10secretion of J774A.1cells and peritoneal macrophages (P<0.05) and suppress LPS-induced release of TNF-α and IL-1β and promote LPS-induced inhibit of IL-10. Intestinal tract macrophages hardly released TNF-α, IL-1β and IL-10and slightly released TNF-α, IL-1β and IL-10treated with EPS without dose-dependent effect. This is that the maintenance of intestinal immune tolerance is of great significance.(5) EPS could significantly promote the phagocytosis neutral red of intestinal tract macrophages at the concentration of the EPS100μg/mL,200μg/mL and400μg/mL. EPS slightly increased NO in culture supernatants of intestinal tract macrophages. EPS not only promoted the phagocytosis neutral red of intestinal tract macrophages, but also slightly increased NO in culture supernatants of intestinal tract macrophages without intestinal inflammation, which played an important role in the intestinal environmental stability.Conclusion:The EPS of Lactobacillus casei could promote the proliferation of J774A.1cells and influence the phagocytosis and secretion of peritoneal macrophages by tow-way regulation, promote the phagocytosis of intestinal tract macrophages, improve inflammatory response and maintain the balance of the intestinal immune system. |
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