| Avian feathers cover a wide range of carapace surfaces and play an important role in insulation,body protection and flight,making them an ideal model for bird biology and poultry science.Based on external morphology and distribution characteristics,feathers are usually classified as ortho,down and cilia.As a light and warm textile material,goose down feathers are widely used in everyday life,mainly for the production of down clothing,duvets and other textile products,which have a high economic value.The formation of goose feathers is closely related to the physiological development of the feather follicles and is regulated by a variety of signalling pathways and growth factors.Among them,Wnt and MAPK signalling are the initial signals for hair follicle growth and are mainly involved in regulating the development of feather follicles in goose embryonic skin,whose growth and development are affected by various factors.ERK phosphorylation and has been widely used in the life sciences as well as in clinical research.Therefore,this thesis firstly investigates the pattern of feather growth and development and hair follicle morphogenesis in Jilin white goose embryos;secondly,it investigates the expression pattern of ERK/Wnt pathway genes in the skin feather follicles of Jilin white goose embryos;secondly,it investigates the effect of embryonic egg injection of AZD6244 on the development of skin feather follicles and feather growth of goose embryos using goose embryos as a model and the preliminary mechanism,aiming to provide a theoretical basis for the genetic improvement of feather traits in Jilin white goose.The aim was to provide a theoretical basis for the genetic improvement of feather traits in Jilin white geese.The content and main results of the study are as follows.(1)The aim was to investigate the pattern of feather growth and development in the embryonic stage of Jilin white goose.A mathematical model(Logistic,Gompertz,Von Bertalanffy)was used to assess the embryonic feather growth and development of Jilin white geese and to predict the quality and length of back,chest and belly feathers at different embryonic ages.The results showed that the primary feather follicles developed at E14 and the secondary feather follicles at E18,and that the primary hair follicle density showed a trend of increasing and then decreasing,while the secondary feather follicle density was on a continuous increasing trend.Logistic curve models fit best in embryonic feather growth and development in Jilin white geese.(2)The aim was to investigate the expression pattern of ERK/Wnt signaling pathway in the embryonic skin feather follicles of Jilin white goose.In this study,immunohistochemical staining techniques,fluorescence quantitative polymerase chain reaction and Western-blot assays were used to localize and quantify key genes and proteins of the ERK/Wnt signalling pathway in the back skin of Jilin white goose embryos(E12,E14,E16,E18,E20,E22,E24,E26,E28,E30).catenin,FZD4,LEF1,TCF4).The results showed that the expression of β-catenin and LEF1 proteins increased and then decreased,and the expression of TCF4 protein showed an overall up-regulation trend,and the expression of TCF4 protein was significantly higher in late embryonic development(E22-E30)than in early embryonic development(E12-E20)(P<0.05).the expression trend of FZD4 protein showed an "M" pattern;while the expression of ERK protein trend was "V" shaped,with lower expression at E20,E22 and E24,with no significant difference(P>0.05).β-catenin and ERK immunohistochemical results were generally consistent with protein immunoblotting assays.mRNA expression of ERK,c-Myc and FZD4 genes were up-regulated with increasing embryonic age,but mRNA expression of LEF1 and TCF4 genes.However,the mRNA expression of LEF1 and TCF4 genes was down-regulated,and the mRNA expression of β-catenin genes showed a trend of increasing and then decreasing.(3)The aim of this study was to investigate the effect of in-egg injection of AZD6244 on the development of feather follicles and feather growth in goose embryos and the preliminary mechanism.In this study,samples were collected from back,chest and belly feathers and skin tissues of Jilin white goose embryos on day 21.5(inflection point of feather growth,E21.5)by intra-egg injection of different doses of the small molecule inhibitor AZD6244,and immunohistochemical staining techniques,fluorescence quantitative polymerase chain reaction and Western-blot assay were used to investigate the role of the ERK/Wnt pathway in regulating goose embryo The results showed that the ERK/Wnt pathway played a significant role in the regulation of feather morphogenesis in goose embryos.The results showed that the AZD6244 injection group significantly inhibited feather width and feather follicle diameter compared with the BLANK and CK groups(P<0.05),and blocked the Wnt/β-catenin signalling pathway by inhibiting ERK protein phosphate levels,which in turn down-regulated the expression of FZD4,β-catenin,TCF4 and LEF1 proteins in the feather follicles of the chest and belly skin(P<0.05).The positive expression of β-catenin and p-ERK protein was significantly reduced in the AZD6244 injection group(P<0.05),and the positive expression of β-catenin and p-ERK protein was mostly concentrated in the epidermis and feather ridge.In addition,embryonic egg injection of AZD6244 significantly downregulated the protein expression and mRNA expression of PCNA in the feather follicles of the chest and belly skin(P<0.05);embryonic egg injection of 5 mg/kg AZD6244 and 15 mg/kg AZD6244 groups significantly down-regulated the relative expression of Bcl-2 and Bax proteins in the feather follicles of the chest and belly skin(P<0.05).Among them,the Bcl-2/Bax ratio in the chest skin feather follicle injection group was significantly lower than all other groups(P>0.05),and the Bcl-2/Bax ratio in the 15mg/kg AZD6244 group in the belly skin feather follicle was significantly lower than all other groups(P>0.05),showing induction of apoptosis.In conclusion,this study found that the embryonic feather growth of Jilin white geese showed a slow-fast-slow trend,and the logistic curve model could better fit the embryonic feather growth and development process of Jilin white geese.The embryonic egg injection of AZD6244 significantly affected feather width and feather follicle diameter,and blocked the Wnt/β-catenin signalling pathway by inhibiting ERK protein phosphate levels.In addition,the above study provides a theoretical basis for elucidating the mechanism of action of small molecule inhibitors in the growth and development of feather follicles in poultry. |
PDF Full Text Request