Research On The Expression And Mechanism Of IGF-1 Family In Skin Tissues Of Cashmere Goats

In this research,16 adult healthy Liaoning cashmere goats (2-3 years old) were selected as the research animals. Skin samples were collected at the body side in the Catagen (February), the Telogen (April), the Proanagen (August) and the Anagen (November), respectively. Using real-time fluorescence quantitative PCR and Western-blot method to measure the expression of mRNA and protein in skin tissue of IGF-1 family. Then by means of hair follicle culture in vitro, hair follicle growth was measured and it was observed their morphological changes. In addition, it was measured that the expression of IGF-1 family genes in hair follicles at different concentrations of IGF-1. The study was conducted to determine the function and mechanism of IGF-1 family genes and proteins in cashmere fibre growth at molecular level in Liaoning Cashmere goat. Results showed that:(1) The expression levels of IGF-1 and its receptor IGF-1R genes was significantly higher in the Anagen than that in the Telogen and the Catagen. The mRNA level of IGFBP-5 gene was highest in the Telogen, which was significantly higher than in the Anagen. The expression of IGFBP-3 gene was higher than that in other stages, and the difference was significant. (2) The expression of IGF-1 and its receptor IGF-1R proteins was significantly higher than that in other stages. The level of IGFBP-5 protein was highest in the growth period, and was significantly higher than that in the growth stage. There was no significant change in the expression of IGFBP-3 protein in the different period of the growth of the villi. (3)Addition of 1 ng/mL and 10 IGF-1 ng/mL in vitro had a significant effect on the growth of hair follicles, were conducive to maintaining the hair follicle morphology, but the high-dose group added (100 ng/mL) had no significant effect on the growth of hair follicles. (4) IGF-1 increased the mRNA levels of IGFBP-5, IGF-1R and IGF-1. Compared with the blank group, the mRNA expression of IGFBP-3 in the 10 IGF-1 ng/mL group was decreased, what in the 1 and 100 ng/mL groups was significantly enhanced.These results indicate that the expression of IGF-1 family genes and proteins was regular in different periods of cashmere fibre growth, and IGF-1 family genes and protein involved in the cyclical growth of cashmere fibre. In the Anagen, mRNA expression of IGF-1 was increased by combined with its receptor IGF-1R, meanwhile, the expression of IGFBP-5 was suppressed. In the Catagen and the Telogen, the expression of IGFBP-5 was increased while the expression IGF-1 and IGF-1R were suppressed.