Study On Immune Organ Damage And Expression Of HSP70/HSP27 In Heat Stress Chicks

Heat stress Phenomenon caused by the feeding of chicks under high temperature conditions,the production performance and immune function of chicks were seriously affected.During the course of heat stress,as universal cytoprotection proteins,HSPs may enhance tolerance to stress,and increase the survival rate of stressed cells.According to this,this paper selection one hundred and twenty 1-day-old lingnan yellow broilers were allotted randomly into control group and heat stress group.Heat stress group with high temperature treatment every day 8:00-20:00 was given to 34-1 Deg.C,respectively,at 14 d,21 d,28 d,35 d slaughtered their thymus?Spleen and bursa.The preparation of paraffin section and projection electron microscopic observation of tissue and cell microstructure,immunohistochemical detection of HSP70 and HSP27 protein in 3 kinds of immune organs in distribution and localization,expression and detection of HSP70 HSP27 mRNA fluorescent quantitative PCR method.Test results show that:1?Histological observation showed: Compared with the control group,the organization structure of heat stress group chicken thymus and spleen and bursal showed varying degrees of damage,caused by the decrease in the number of thymocytes.Hassall's bodies severely degraded in the spleen;The spleen nodule germinal center is not obvious,the tissue becomes delivery,and the peripheral l ymphatic sheath becomes thinner;The number of lymphoid follicles in the bursal decreased,the skin and medulla were fuzzy,compared with the same age,the immune organs of the heat stress group were poor,and the tissue damage was obvious.2?Observation of cell ultrastructure: The apoptosis and necrosis of the thymus were increased in heat stress group,and most of the chromatin in the nucleus of the thymus cells had aggregation phenomenon,and the cytoplasmic organelles were swollen and degenerated;The loose structure of lymphocytes in the spleen,nuclear heterochromatin decreased,most of them show the edge set trend,increased number of mitochondria,abnormal structure;The lymphocytes in the bursal also had the phenomenon of chromatin aggregation.THE middle concentration trend is obvious.The rough endoplasmic reticulum in the cytoplasm of the ribosome shedding phenomenon obviously,mitochondrial swelling and vacuolization,most cells arranged loosely,early signs of apoptosis.3?Immunohistochemistry test results showed that: HSP70 protein positive signal in the cytoplasm of thymus and spleen cells is obvious,and the bursal is mainly concentrated in the nucleus.The positive signal intensity of heat stress group at 4 days of age were higher than that of control group.THE increase of thymus and spleen was large,and the bursal of HSP70 was not obvious.The expression intensity of HSP27 was close to that of normal thymus,spleen and the bursal of fabricius.The cytoplasm and nuc leus of the thymus cells had positive signals,HSP27 in the spleen was mainly expressed in the nucleus,And the positive signal of HSP27 in bursal was mainly expressed in the cytoplasm.The expression intensity of HSP27 was also greatly increased under heat stress,but there was no obvious linear relationship between the age and the age.4?HSP70 and mRNA HSP27 expression detection results show that: In heat stress group,the expression of HSP70 mRNA in thymus and spleen showed a decreasing tendency with the increase of day old,while the bursal of showed an increasing tendency,which was obvious higher than that in control group(P < 0.05).From the HSP27 mRNA expression distribution trend can be seen that the expression of HSP27 mRNA in spleen and bursal of heat stress group was decreased with the increase of day old.The rate of decline has slowed down gradually.There was no difference between the control group of HSP27 mRNA in the bursal to 35 d(P>0.05).There was no obvious correlation between the changes of HSP27 mRNA in the thymus and the days old,but the expression of heat stress group was obvious higher than that of the control group.However,the expression of heat stress group was obvious higher than that in control group.May prompt that the body in the long-term Under thermal stimulation,has been produced the tolerance phenomenon.Heat shock protein auxiliary cell repair and other anti-stress function is no longer the main means of anti-stress.In summary,heat stress can cause obvious damage to the Immune organ tissue structure of chicken,which leads lymphocyte apoptosis or necrosis,and decreased proliferation ability;The distribution and expression of HSP70 and HSP27 protein in lymphocytes were obvious up-regulated,and the expression of HSP70 and HSP27 mRNA of organization was also increased.The expression of HSP70 mRNA in the thymus and spleen was positively correlated with the expression of HSP70 protein,but there was no obvious correlation between the expression of HSP27 mRNA and prote in synthesis.The above results can provide a theoretical basis for the study of the mechanism of heat stress injury.