| Immunity of human usually decreases as aging and the decline of immunity has several bad effects: the decrease of resistance to pathogenic microorganisms, the decrease of response to the vaccine, the occurrence of infectious diseases and autoimmune diseases. Exploring the mechanism of immunity's decline as aging would have great significance in improving the quality of life for elderly people.In the course of evolution, fishes first have equipped with immune system which like human immune system. Most fishes have got adaptive immune system based on T cells, B cells and IgM antibodies. Nothobranchius is annual teleost from African continent which exhibit short life cycle and become a vertebrate model for aging and anti-aging research. Therefore, we take advantage of this annual fish for the research of age related changes of immune system. Resveratrol, a naturally polyphenols found in grape, extended lifespan of yeast, nematodes and fruit flies and have been reported to improve immune function in several animals. However, the effects of resveratrol on age-related changes of immune system in Nothobranchius keep unclear. The effects of resveratrol on immune system as aging process were explored in the fish via the detection of relevant indicators.N. guentheri was divided into experimental group and control group when they are grown to 3 months old, the experimental group was fed with supplement of resveratrol and no resveratrol was added to the food in control group. The fish was killed on ice at the age of 3, 6 and 9 months old and kidney, spleen and blood was harvested. Then, effects of resveratrol on immune organs, lymphocytes and cytokines were detected. The results as following:1. Kidney index of the fish decreased while spleen index increased as age. Resveratrol improved kidney index and reduced spleen index. For histological structure of kidney, tubular and renal interstitial cells arranged closely and lots of hematopoietic tissue could be seen in 2.5 and 4 months group; in 9 and 11 month group, the wall of renal tubules and collecting tubules thickened, the number of epithelial cells decreased and their arrangement disordered, renal interstitium came fibering with hematopoietic tissue loss. For spleen, in 2.5 and 4 months group, there was little connective tissue, abundant lymphocytes and hematopoietic tissue; in 9 and 11 month group, there was a significant reduction of lymphocyte count with some enlarged nuclei; and fibrous tissue and mononuclear(macrophage) cells increased. Resveratrol significantly delayed these aging changes mentioned above.2. The blood cells of N. guentheri contain red blood cells, lymphocytes, neutrophils, eosinophils, monocytes(macrophages) and thrombocyte. The size of these cells are similar than that in zebrafish. There is a significant reduction in number of lymphocyte as aging process, but the number of neutrophils and thrombocyte did not change significantly. Lymphocyte count increased significantly by long term resveratrol treatment at 9 month group.3. The activities of alkaline phosphatase(AKP), acid phosphatase(ACP), lysozyme( LSZ) and catalase(CAT) were examined in fish at 3, 6 and 9 month old. The results showed that activities of the four enzymes decreased as aging. Resveratrol treatment significantly increased activities of AKP and ACP in serum and LSZ and CAT activities in kidney.4. The changes of activity of NOS, levels of NO and COX-2 with aging and effects of resveratrol on them were detected. The results showed that the activity of iNOS and the level of COX-2 were significantly increased as aging. Resveratrol significantly inhibited iNOS activity and level of COX-2.In short, resveratrol delayed aging changes of immune organs histologically, improved lymphocyte count and the activities of immune-related enzymes, and regulated the activities and level of some cytokines in the fish. This implied that resveratrol can delay age-related change of immune system in the fish. |
PDF Full Text Request