Hormonal And Growth Factor Changes And TGF-β Signaling Pathway In Velvet Growth Stage Of Père David’s Deer

The Père David’s deer(Elaphurus davidianus)has the characteristics of earlier than other deer velvet,but there are few studies on the regulation of Père David’s velvet antler growth.In this study,Père David’s deer was used as the research object to explore the variation rule of antler shed and velvet growth and molecular changes related in the stage of velvet growth of Père David’s deer which provided a theoretical basis for the resource development of Père David’s deer antler velvet.In the experiment,nine healthy Père David’s deer,with similar birth dates,excellent physical condition and similar weight were selected and fed in separate cages before the winter solstice,and the pre-trial period was 14 days.According to the shed of old antlers and the growth of new velvet,the experiment was divided into 5 stages included as the stage with old antlers,the stage before antler shedding,the stage before velvet growth,the stage of velvet growth index,or the stage after velvet growth and the experiment period was 90 days.The experiment results were as follows:1.The growth rule of antler shed and velvet growth of Père David’s deer had shown that: In the velvet growth stage,with the growth of velvet,the length of velvet,the circumference of the trunk,the mouth head length,the length of the eyebrow branches,and the weight of the velvet increased significantly(P<0.05).The vascular content of velvet cartilage increased significantly(P<0.05),while the content of collagen fibers decreased significantly(P<0.05),and the chondrocytes density increased significantly in the stage of velvet growth index(P<0.05)and decreased significantly in the stage after velvet growth(P<0.05).2.Blood biochemical indexes in the stage of antler shed and velvet growth of Père David’s deer showed that: The serum MT,GH and IGF-1 of Père David’s deer before dehorning decreased significantly(P<0.05),E2 increased significantly and then fell back(P<0.05),and serum TP,ALB and BUN content decreased significantly(P<0.05);in the velvet growth stage,MT,E2 and IGF-1continued to increase in the velvet growth stage,and the stage after velvet growth was significantly higher than that in the stage before velvet growth(P<0.05),and the serum contents of TP,ALB,Ca,P or VD were significantly higher(P<0.05),PTH increased significantly(P<0.05)and serum Ca or P content decreased significantly(P<0.05)in the stage after velvet growth.3.The growth factor and TGF-β signaling pathway in velvet growth stage of Père David’s deer showed that: the TGF-β1 content of cartilage tissue in stage of velvet growth index of raw mushroom increased significantly(P<0.05),Bcl-2/Bax increased significantly(P<0.05),and the TGF-β1/Smads/Fox M1 pathway mRNA expression was active,indicating that cartilage proliferation was vigorous;The contents of IGF-1,TGF-β1 and VEGF decreased significantly in the stage after velvet growth of raw mushrooms(P<0.05),and Bcl-2/Bax decreased significantly(P<0.05),indicating that cartilage proliferation slowed down and new angiogenesis decreased.The BMP2/Smad1/Runx2 pathway mRNA expression was active in the stage of velvet index and the stage after velvet growth,and chondrocytes were strongly differentiated.In summary,the antler growth of Père David’s deer exhibited significant changes in appearance and tissue structure,which required complex changes in blood biochemical factors in the Père David’s deer body to regulate.At the same time,the growth of Père David’s deer antler also depended on the proliferation and differentiation of chondrocytes.