| Rex rabbit is famous for fur and meat production,and has become a new hot spot of aquaculture in China.For Rex rabbit production,skin quality is the most important economic trait for the hair characteristics of short,flat,thick,thin,beautiful and firm.The primary index to evaluate skins of Rex rabbit include wool density,wool length,bristly wool rate,wool fineness and surface area of skin,of which wool density and surface area of skin is the most important index.In recent years,how to improve the quality of fur has become the most important concerns in Rex rabbit production.Research results of goat and mink results had showed that there was a close relationship between the number and structure of the hair follicle and fur quality and yield.As a relative new aquaculture animal,there was few studies of wool density and follicle development on Rex rabbit.Based on the developmental pattern of Rex rabbit's hair follicle,we establish the Rex rattit model in vivo and the organ cultured in vitro,to investigate the role of Wnt10 b on Rex rabbit hair follicle cycle and the effect on hair follicle development and methionine regulation hair follicle development mechanism by using animal feeding test.For the purpose to provide the technical support for nutrition regulation Rex rabbit fur quality and a scientific basis for improving the fur quality of Rex Rabbit.1.The hair follicle development of Rex rabbit from birth to 8-weeks old We investigated the hair follicle development of Rex rabbit through histologic section,and also measured the depth of epidermis and dermis.The results showed that at 0-week old,the hair follicle of dorsal skin is mainly the primary follicle,and there have few second follicle around the primary follicle.At 2-weeks old,the second follicles around primary follicle increased almost to two or three.At 4-weeks old,the second follicles increased unsignificantly but the diameter of primary follicle increased obviously.The second follicles around primary follicle differentiation increased significantly.Structure of lengthwise slip we found that at 0-week old,most of the hair follicles of dorsal skin were in the state of anagen.At 2-weeks old,some of the hair follicles had turn into the catagen.At 4-weeks old,there were three types of hair follicle in dorsal skin,anagen,catagen and telogen.And we also observed the phenomenon that the diameter of hair follicles was significantly larger.Themajority of hair follicles stayed at anagen at 6 and 8-weeks old.The average thickness of epidermis and dermis changed significantly(P<0.05).The least thickness of epidermis lied in 4 and 6-weeks old,while the least thickness of dermis lied in 0 and 4-weeks old.The results indicate that there was the hair follicle cycle of Rex rabbit.2.Expression profiles of hair follicle development related genes in rex rabbits during the first 8 weeks of life We analyzed the genes expression of IGF-I,IGF-IR,EGF,BMP2,FGF-5,Kap3.1,Kap6.1,GHR,TGF?-1,TGF?-2,TGF?-3 in the dorsal skin of Rex rabbit from birth to 8-weeks old.The result showed that all of the genes are expressed in dorsal skin at 0-week old.The IGF-I,EGF,TGF?-2,TGF?-3 transcript levels at 2-weeks old were significant lower than at birth(P<0.05)but gradually increased thereafter.The IGF-IR m RNA expression decreased at first and then increased,the transcript levels were significant lower at 2 and 6-weeks old than 0 and 8-weeks old(P<0.05).The TGF?-1 transcript levels increased significantly at 2 and 4-week old than 6 and 8-week old,and with the highest expression at 2-week old(P<0.05).The Kap3.1 transcript levels increased with age,with the highest expression at 8-weeks old(P<0.05).The Kap6.1 transcript levels remained stable between birth and 4-weeks old but were higher at 6 and 8-weeks old than during the first 4 weeks of life(P<0.05).The GHR(P<0.05),FGF-5(P<0.05)and BMP2(P<0.05)transcript levels were significant higher at 2 weeks old than at birth and decreased at 4-weeks old and then increased.3.The Wnt10 b expression in the hair follicle cycle of Rex rabbit We analyzed the Wnt10 b and ?-catenin m RNA and protein expression in dorsal skin of Rex rabbit from birth fo 8-weeks old.The result showed that there was no difference of Wnt10 b m RNA expression among 0 to 8-weeks old(P>0.05),while the ?-catenin m RNA expression changed significantly(P<0.05).However,the analysis of Wnt10b(P<0.05),?-catenin(P<0.05)and Dsh(P<0.05)protein expression reached the lowest at 2 and 4-weeks old.The protein expression of Wnt10 b and ?-catenin did not match to the m RNA expression.It may be related to the post-translational modification of protein.By immunohistochemistry staining,we observed that the Wnt10 b protein expressed specifically in the matrix of anagen hair follicle,and also expressed in the outer and innerroot sheath.In catagen hair follicle of Rex rabbit,Wnt10 b protein expressed in the outer and inner root sheath.In telogen hair follicle,there was rare expressed of Wnt10 b protein in follicle.4.The effect of Wnt10 b in hair follicle cycle of Rex rabbit and the signaling pathway of Wnt10 b To further study the effect of Wnt10 b in hair follicle cycle,we establish the Rex rabbit model in vivo and the organ cultured in vitro.Using whisker hair follicle of Rex rabbit in vitro organ culture,we detected that the elongation length of hair shaft of the cultured whisker hair follicles treated with Ad Wnt10 b were lengthened significantly than control group(P<0.05).After Ad Wnt10 b injected in the Rex rabbit model,the hair growth of injected site growed rapidly than uninjected site,which indicated that Wnt10 b can induce hair follicle growth.XAV-939 can inhibit the Wnt/?-catenin signaling pathway specifically.Using whisker hair follicle of Rex rabbit in vitro organ culture,we detected that the elongation length of hair shaft of the cultured whisker hair follicles treated with XAV-939 were shortened significantly than control group(P<0.05).After XAV-939 injected in the Rex rabbit model,the hair growth of injected site growed slowly than uninjected site,which indicated that Wnt10 b transduce through the Wnt/?-catenin signaling pathway.5.The effect of different Met on the related genes of hair follicle development Two hundred weaner Rex rabbits were randomization into 4 groups with 50 replicates in each group,in which they were fed diet with 0,0.3%,0.6%,0.90% Met addition.The result showed that with the feeding time increasing,the effect of Met level to the genes expression of IGF-I,IGF-IR,EGF,BMP2,FGF-5,Kap3.1,Kap6.1,GHR,TGF?-1,TGF?-2,TGF?-3 was different.We found that the higher Met addition can reduce the BMP2 m RNA expression in the dorsal skin of Rex rabbit after feeding 40 d.The m RNA expression of Kap3.1 only had significantly changes after feeding 60 d and the 0.60% Met treatment was significantly higher than others(P<0.05).While the transcript level of Kap6.1 didn,t match with the expression of Kap3.1.The transcript level of EGF showed significantly after feeding 60 d,the 0.30% and 0.60% Met treatment were significantly higher than others after feeding 60d(P<0.05).The result also showed that the transcript level of TGF?-1,TGF?-2 and TGF?-3 changes with the feeding time increase by different dietary Met levels.The appropriate supplementation of methionine in diet could reduce the the transcript level of TGF?-1 and TGF?-3.We also analyzed the transcript level of GHR,IGF-?,IGF-?R.We found that with the feeding time increase,the RNA expression of GHR,IGF-?,IGF-?R didn,t show some regular dynamic changes.6.The effect and mechanism of Met on the hair follicle development of Rex rabbit.After feeding different Met levels of diet for 60 d,we investigated the hair follicle development of Rex rabbit through histologic section.The result showed that the wool density of 0.30%,0.60% and 0.90% Met add group were higher than the control group(P<0.05).Using whisker hair follicle of Rex rabbit in vitro organ culture,we detected that the elongation length of hair shaft of the cultured whisker hair follicles treated with 30 m M,60 m M,90 m M and 120 m M Met treatment were lengthened significantly than control group and 150 m M treat group(P<0.05).It indicated that appropriate concentration of Met can promote the growth of hair follicle.We detected the protein expression of Wnt10 b and Wnt/?-catenin signaling pathway related protein in dorsal skin of different Met level treatment Rex rabbit.The result showed that with the feeding time increase,the expression of Wnt10 b,total ?-catenin,?-catenin(s33+s37)and Dsh protein had some regular dynamic changes.Appropriate Met level of diet can improve the Wnt10 b,total ?-catenin,?-catenin(s33+s37)and Dsh protein expression level.We also found that the expression patterns of total ?-catenin,?-catenin(s33+s37)and Dsh protein were similar to the expression pattern of Wnt10 b,of which indicated that some relationship between Wnt10 b and Wnt/?-catenin signaling pathway.Conclusion In our study,we found that there was the hair follicle cycle of Rex rabbit.There was time-space interrelation between Wnt10 b and hair follicle cycle through Wnt/?-catenin signaling pathway.We also found that Met can promote the growth of hair follicle in Rex rabbit and it may be play the regulatory role through Wnt/?-catenin signaling pathway. |
PDF Full Text Request