| One important factor that influences the economical traits of chicken including body weight of is the development of bone, tibial length is positive correlate with the development of whole skeleton system, but diseases come with the improvement of growth rate. It has been reported that skeleton development and maturation were modulated by interact of multiple molecules. BMP6 is one of the members of BMP family, can modulate the development of skeleton system by play a role in SMAD signaling pathway, but whether BMP6 play a role in the development of long bone and whether BMP6 modulates bone development by influence other signaling pathway is still to be explored. The object of current study is to resolve this question.Two broiler breeds including Avian and Yellow bantam which have huge differences on carcass traits were utilized in this study. We first investigated the expression pattern of BMP6 on the femoral growth plate and tibial growth plate on different time point of bone development and analyze the relationship between BMP6 expression and bone growth. We further compared the growth rate and BMP6 expression level of cartilage cell extracted from both breeds. Last, we induced the growth of cartilage cell by treat with growth factor. And knock down the expression of BMP6 by transfect with BMP6 specific siRNA, and investigate the expression of multiple molecules represent for multiple pathways to expand of knowledge of pathways that modulated by BMP6. Results as follow:(1) No marked difference was found after compare the carcass traits measured on both line on embryo and first day after hatch. On day 40, carcass traits (body weight, leg weight, femoral bone weight, tibial weight, femoral bone length, tibial length, femoral bone diameter, tibial diameter) of individuals from Avian are significant higher than individuals from Yellow bantam. On day 70, carcass traits of male chicken from Avian are significant higher than male chicken from yellow bantam except for tibial length and tibial diameter. And female from Avian line possess the higher carcass traits compared with female from Yellow bantam.(2) The difference of BMP6 expression was found to be not significant after compare the femoral growth plate and tibial growth plate of both breeds, suggest BMP6 did not play a critical role on the maturation but may play a role on the differentiation of chicken femoral growth plate and tibial growth plate.(3) After compared the BMP6 expression on cartilage cell extracted from both breed, we found a significant increase on day 4, but the growth curve of cartilage cell were found to be the same between two breeds, and the proliferation rate and expression of BMP6 are also found to be on the same level, indicate BMP6 expression play a role the proliferation and differentiation of chicken cartilage cell.(4) After treated with growth factor, we found cartilage cells were most sensitive to the concentrate of 50ng/?l, the proliferation was significant on 48 hour, expression of BMP6 was also increased significantly(P<0.05). After knock down of BMP6, expression of Col ? and ColX were significantly (P<0.05) decreased on 48 and 72 hours after transfect. Hence, we think BMP6 play a role on the differentiation of cartilage cell.(5) When cartilage cell was inhibited by the reduced expression of BMP6, expression of IGF1R?JAK2?PKC?PTH and PTHrP respectively was not significantly different on 48h after transfect with BMP6 siRNA, but significantly(P<0.05) decrease on 72h compared to control. Expression of Ihh was significantly decreased on 48h and 72h time point. These results suggest that IGFlR/JAK2/PKC/PTH/Ihh/PTHrP genes contribute to the proliferation and differentiation of cartilage cell modulated by BMP6.In general, BMP6 can contribute to the differentiation and development of chicken skeleton system on early phase, and may due to the regulation of IGF1R/JAK2/PKC/PTH/Ihh/PTHrP genes. |
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