Immunomodulatory and radioprotective property of glucans isolated from lactobacillus species

Bacterial exopolysaccharides (EPS) have been reported to protect the radiation induced damage during radiotherapy. Recent studies suggested that, lactic acid bacteria (LAB) and their secreted products have unique radioprotective properties. In the present study, we evaluated the ability of EPS isolated from two LAB species i.e., Lactobacillus acidophilus and Lactobacillus plantarum as a radioprotective agent against radiation induced mice small intestinal damage. EPS was isolated, identified as glucan and named as glucan A (GA) derived from Lactobacillus acidophilus and glucan P (GP) derived from Lactobacillus plantarum. GA and GP were subjected to in vitro immunomodulatory and in vivo radioprotective activity. Both GA and GP exhibited significant mitogenic activity and increased interleukin-2 (IL-2) and interleukin-10 (IL-10) secretion in a dose dependent manner. Similarly, after 9Gy whole body irradiation, glucan pre-treated mice showed improved spleen weight, reduced radiation induced hematopoietic disorder and radiation enteritis when compared to the irradiation control mice. Both glucans were also protected mice from early death and increased survival rate when compared to irradiation control. As a result, it is possible that glucan from Lactobacillus acidophilus and Lactobacillus plantarum could be served as a novel radioprotective agent to inhibit radiation-induced intestinal damage.