Study On The Changing Rules Of IL-21in The Ostrich Immune Organs Development

Ostrich, all part of the body is of much value, has a high value of feeding. Young ostrich is in the growing period, each organ system is not yet fully developed, and are vulnerable to the invasion of various pathogenic factors, and induce a disease that affects their healthy growth.Immune system is an important barrier of the body to resist external pathogenic factors, it is fulfilling its functions through the T and B cells, the degree of immune organs development determines the ability of the body’s resistance to diseases.The brood stage of ostrich need a long period of time, ostrich growth and development is fast in that period, vulnerable to the invasion of external agents.In order to improve the survival rate of the ostrich brood, to reduce the incidence of this disease, related scholars have done a lot of research. But until now, the regular pattern related to the development of the ostrich immune organs yet not been reported.IL-21is a cytokine discovered in2000by Parrish-Novak et al.,the University of Washington;IL-21secrete mainly by activated CD4+T, NKT cells, it regulate the function of T, B and NK cells, and play a leading role in the immune globulin regulation and production.IL-21studied at internal and abroad mainly in the IL-21and related diseases, while the distribution of IL-21and variation with age in the ostrich immune organs yet has no reported.For these reasons, this test using HE staining and immunohistochemical positioning expression (SABC staining) technology, studied the organization of the ostrich immune organ morphology and developmental variation of IL-21distribution and variation in the immune organs, in order to provide a theoretical basis on ostrich disease prevention and treatment. Results are as follows:Firstly, the histological variation of ostrich immune organs were studied. This experiment select Id,30d,60d,90d and334d health ostrich as test objects, and use of paraffin sections, HE staining, study the organizational characteristics and age variation in thymus, spleen and bursa of the ostrich.Results are as follows:Thymic cortex and medulla area ratio gradually decreased with age increase; in the thymic medulla observed three forms of thymic corpuscles, followed by a single cell type, concentric type and massive thymic corpuscles, single cell type appeared earlier, may be associated with the development of thymus cells, concentric type and lumpish type appeared later, and may be related to the apoptosis of thymocytes.Capsule thickness of the spleen with age growth showing a clear upward trend,and reach the maximum biofilm thickness at334d; the periarterial lymphatic sheath and ellipsoid can be observed at Id spleen, and the periarterial lymphoid sheath and ellipsoid area was significantly increased with age tendency to increase,the splenic follicles of the spleen can be observed in30d, and the number of splenic increased with day age grow.Bursa of the summary area and medulla area increases with age grow,the summary trend of cortical thickness of the capsule first increase and then decrease with age increases. Lamina propria of loose connective tissue with age growth summary transfer to the medulla and at the age of334d,the medulla basic filling with loose connective tissue, the function of the bursa has receded at this time, the bursa fabricius has already begun to atrophy.Secondly, the distribution of IL-21in ostrich immune organs with age variation were studied.This study select Id,15d,30d,45d,60d,75d,90d and334d health ostrich as test objects, use paraffin sections and immunohistochemical techniques,to study IL-21positive cells morphological features, distribution and development change rule in the ostrich immune organs.The results as follows:IL-21-positive cells in the thymus were round and oval, mostly distributed around the thymic corpuscles in the thymic medulla, and also distributed at the cortex and medulla junction and cortex;IL-21expression intensity and the number of positive cells in the thymus with age growth was in the gradual increase and then downward trend, the expression intensity and the number of IL-21positive cells peak at75d.In the spleen,IL-21were mainly distributed around the periarterial lymphoid sheath and ellipsoid around the lymphatic sheath,and its expression intensity and the number of positive cells peak at90d,showing the trend of increased and then decreased with age growth. Compared with the thymus and spleen, the intensity expression of the IL-21in the bursa and the number of positive cells were much lower than them,positive cells were mainly expressed in the lamina propria,and positive cells express intensity first increased and then decreased with age growth, reached its peak in90d.These results suggest that IL-21were distributed in the ostrich thymus, bursa fabricius and spleen,its may be involved in the conversion of the innate immunity to acquired immune,the distribution IL-21has a certain regularity, IL-21expression intensity and expression levels increase with age gradually increased in1to90d.These changes can be inferred of IL-21may be involved in T, B-cell proliferation and differentiation,induce T and B cell apoptosis,thus play an important role in the development of immune organs.