Preliminary Investigation On The Changes Of Immune Function In Mice Induced By Hydrogen Sulfide Exposure In Breeding Environment

Hydrogen sulfide?H2S?is a toxic and harmful gas.About 50%of the H2S pollution in environment is from the livestock and poultry industry.The problem of environmental pollution is also becoming more and more serious,which has caused great harm to the living environment and seriously affected the health of humans and animals.Low-concentration exposure mainly stimulates the respiratory tract and eyes,and high concentration exerts a significant effect on the whole body,displaying as central nervous system symptoms and direct inhibition on the respiratory center.H₂S is widely distributed in the living environment of livestock and poultry,which seriously decrease disease resistance and weaken their body.In this study,160 KM mice of 30 days old were selected and divided into 4 groups after 7 days of routine feeding.By simulating the environment of livestock and poultry breeding,H₂S with 5 ppm,10 ppm and 15 ppm concentrations were set in the environment of breeding mice for 21d.The immune organs of mice,the main immune indexes of serum,the transforming function of spleen lymphocytes,the phagocytosis of peritoneal macrophages,and the changes of apoptotic factors in serum and immune organs were detected to obtain the changes of the immune function of the animal body caused by H₂S exposure.It provides a reference for scientifically controlling the concentration of harmful gases in production and improving production performance..The main research findings are as follows:1.Organ index and tissue structure of thymus and spleen.Organ index of thymus and spleen:Three experimental doses of H₂S increased thymus index.Compared with the control group,the thymus index of the experimental group 2 and group 3 were significantly increased?P<0.05?,no significantly change was observed of experimental group 1.The spleen index decreased with the increase of H₂S concentration,and the spleen index of each treatment group was not significantly different?P>0.05?.The histological structure of thymus and spleen:In control group,more thymus lobules were observed and the thymus lobules were normal in structure;In the 5 ppm and10 ppm H₂S treatment group,the cortex area decreased,the medulla occupied most part of the lobules,more thymic corpuscles were seen.In the 15 ppm H₂S treatment group,the boundary between lobules was blurred,the numbers of lobules decreased.The cortex became thicker and the thymic corpuscles increased.The structure of spleen with microscope showed:Compared with the control group,no obvious change was observed in the white pulp structure in the 5 ppm H₂S treatment group,the periarterial lymphatic sheaths thickening and increasing of spleen nodules in size slightly occurred.H₂S of 10ppm decreased the white pulp in size,spleen nodules was clear,more multinuclear macrophage were observed.H₂S of 15 ppm made the structure of spleen and spleen nodules indistinct,decreased the numbers of lymphocytes,while increased the numbers of the multinuclear macrophage.It indicated that the test dose of H₂S delayed the atrophy of the thymus,the proliferation of spleen lymphocytes was impaired,and the immune function of the spleen decreased.2.Changes of serum immune index under different concentrations of H₂S.Compared with the control group,IgG level was decreased in serum?P<0.01?.IgA was decreased under a H₂S concentrations of 5-15 ppm?P<0.05?,and IgM level was decreased under a H₂S concentrations of 15 ppm?P<0.05?,IL-8 level was increased under a H₂S concentrations of 5-15 ppm?P<0.01?,and the level of IL-6?P<0.05?increased with15 ppm concentration of H₂S.3.Changes in phagocytosis rate of peritoneal macrophages and lymphocyte transformation rate of spleenThe phagocytosis rate of peritoneal macrophages in each experimental group showed a significant decrease with the increase of H₂S concentration.Compared with the control group,the experimental group 1,2,and 3 decreased by 23.77%?P>0.05?,70.49%?P<0.05?and 77.05%?P<0.05?respectively.The difference between the three experimental groups was not significant?P>0.05?;with the increase of H₂S concentration,the lymphocyte transformation rate of spleen showed a significant downtrend.Compared with the control group,the experimental group 1,2,and 3 decreased by 28.27%?P>0.05?,60.07%?P<0.05?and 66.08%?P<0.05?respectively.4.H₂S causes changes in the expression of apoptotic factors in serum and immune organs.No significant effect were found on the serum expression levels of apoptotic factors Caspase-3,Caspase-9 and Bcl-2 by experimental dose of H₂S?P>0.05?,and the content of apoptotic factor Bax showed a significant increase with the increase of H₂S concentration?P<0.05?.The results of apoptotic factors in the thymus tested by ELISA showed:15 ppm concentration of H₂S significantly increased the expression of Caspase-3?P<0.01??Caspase-9?P<0.05??Bax?P<0.05?,the expression of Bcl-2 was significantly decreased?P<0.01?with the 10 ppm and 15 ppm concentration of H₂S;The results of apoptotic factors in the spleen tested by qRT-PCR showed:Compared with the control group,the relative expression of Caspase-3?P<0.05??Caspase-9?P<0.05?mRNA decreased in the group of 15 ppm H₂S.The expression of Bcl-2?P<0.05?,Bax?P<0.01?mRNA decreased with 10 ppm and15 ppm concentrations of H2S.Conclusion:1.H₂S above 10 ppm in the environment reduces the humoral immunity and non-specific immune function of the body,induces the body's inflammatory response,resulting in weak constitution.2.The concentration of 15 ppm H₂S in the environment can significantly increase the expression of apoptotic factor mRNA in thymus and spleen,and reduce the immune function of the body by promoting the apoptosis of immune organs in mice.