Studies On The Natural Mechanism Of The Anti-Schistosomasis Japonica In Microtus Fortis

To further explore the mechanism of the nature anti-schistosomasis of Microtus fortis , experiments of gene difference expression between mice and Microtus fortis infected with Schistosoma japonicum with cDNA microarrays were done firstly. Gene difference expression of the lung tissues between of mice and Microtus fortis infected with Schistosoma japonicum for 7 days, and the lung tissues and the liver tissues of Microtus fortis infected with Schistosoma japonicum for 12 days were analyzed by cDNA microarrays. The results showed that serine protease inhibitor genes expression were up-regulated and immune-associated genes expression were not obviously changed in the lung tissues of mice. On the contrary, serine protease inhibitor genes expressed constantly in the lung tissues of Microtus fortis infected with Schistosoma japonicum for 7 days and Several non specific immune associated genes (such as lysozyme gene and cathepsin genes) were up-regulated. At the same time, some important specific immune associated genes (such as CD74 MHCⅡand MHC I) were up-regulated, too. The lung tissues and liver tissues of Microtus fortis infected with Schistosoma japonicum for 12 days confirmed the results by enhancing expression of the non specific immune associated genes and specific immune associated genes. Furthermore, in the lung tissues of Microtus fortis infected with Schistosoma japonicum for 12 days serine protease inhibitor genes expression were down-regulated. It was suggested that the mice and Microtus fortis share reverse expression patterns. Meanwhile, apparent characteristics of lungs or livers in mice and Microtus fortis infected with Schistosoma japonicum were observed. dering early 10 days after infection, the bleeding phenomena occurred in lungs of mice and Microtus fortis. 10 days later, the bleeding phenomena disappeared and schistosomula-induced granuloma began to occur in the liver of Microtus fortis , but apparentness of the liver in mice kept normal until eggs-induced granuloma gradually emerged 30 days later. In the liver of Microtus fortis, a few granuloma began to emerge in 6^th day after infection , and more and more serious until infected for 12-14 days. After 20 days the granuloma in liver of Microtus fortis disappeared. That meant Microtus fortis had continuous and active and systemic anti-infectious process.So peculiar immune mechanism of Microtus fortis was paid more attention. The effectiveness of immune mechanism of Microtus fortis were studied by injecting the immune inhibitors, Dexamethasone and Cyclophosphamide, in order to change the level of immunity and explore the function of immunity in nature anti-schistosomasis of Microtus fortis. The results of animal experiments shown that the granuloma caused by Schistosoma japonicum did not display in the liver of Microtus fortis injected with Dexamethasone or Cyclophosphamide, and that Schistosoma Japonic um was still stunted in growth and finally disappeared in the host, comparing with the control experiments. It revealed that other more important mechanism was probably playing more significant role in the nature anti-schistosomisis of Microtus fortisbesides the immune function. After normal mice sera and sheep sera were transferred to Microtus fortis respectively, the longevity of schistososmulum prolonged and the big granuloma appeared. It suggested that the sera from the adaptive host of Schistosoma japonicum contain some materials which could sustain the growth and development of schistosomulum. The results of the studies shown that the mechanism of nature anti-schistosomasis of Microtus fortis included not only the immune function but also certain mechanism that prevent Schistosoma japonicum from obtaining some materials that could sustain the growth and the development.The difference expression genes in cDNA microarrays experiments, like serine protease inhibitor, lysozyme, cathepsin, levamisole and IGF-1, were focused. They were injected into different hosts, like rat, mice and Microtus fortis, respectively, to examine the expected effect. But except that levamisole could enhance schictosomula-killing effect of mice and rat to a lesser extent, other reagents like lysozyme and cathepsin had no effect on mice. Serine protease inhibitor and IGF-1 had not supported the growth and development of schistosomulum. For that, more deep research would be expected.Nitric oxide (NO) was as a major signaling molecule in the immune system and played an important role in modulating immune responses, so NO level in serum of mice and Microtus fortis infected with Schistosoma japonicum was analyzed. The change of serum NO in Microtus fortis showed a integrated and regular cycle, from 100μmol/l to 16μmol/l, then returned 100μmol/l within 20 days. But for mice, serum NO level fluctuated, until 36 days later NO level kept in a low level, 0-10μmol/l. That meant Microtus fortis , infected with Schistosoma japonicum, taken on a more sensitive, continuous and systemic inflammatory response than mice.In the article, author discovered, for the first time, that the dark material in the intestine of Schistosoma japonicum was not only coloring material, but also true organism in substance, called K materia. Using optical microscope and electron microscope, we could clearly see the comma shape of K material and interaction between K material and erythrocyte. K material could adhere to the surface of erythrocyte and produce its own hypha to digest and absorb erythrocytes. After that, the hypha reproduced new comma-like K material. The author thought it was possible that K material decomposed erythrocyte to supply the host with the digested product to maintain the host. Because K material was sensitive to lysozyme and lysozyme gene in the lung of Microtus fortis up-regulated after infection, the author thought that the mechanism of nature anti-schistosomasis of Microtus fortis should include the mechanism of interaction between lysozyme and K material.