Abstract:

 This study aimed to investigate the regulation of IGF-1 on promoting hair growth and development by studying the effect of IGF-1 on alpaca skin fibroblasts. In this study: (1)Analyzing the expression of IGF-1 and its receptor IGF-1R in the alpaca skin and cultured fibroblasts by using immunohistochemical and immunocytochemistry techniques. (2) Observing the effect of recombinant human IGF-1 in vitro with different concentrations on the proliferation and morphological changes of cultured alpaca skin fibroblasts. (3) Detecting the expression quantity of IGF-1,TGF-β1 and KGF genes in fibroblasts cultured in different IGF-1 concentrations by using QRT-PCR technology. Result: (1)The result of IGF-1 and its receptor IGF-1R protein expression was positive in the alpaca skin and cultured fibroblasts. (2) Adding IGF-1 had significant growth promoting effect on the quantity and morphology of fibroblasts, especially the addition of 10 ng·mL^-1. (3)IGF-1 could affect the gene expression of IGF-1R,transforming growth factor β1(TGF-β1) and keratinocyte growth factor(KGF) in alpaca skin fibroblasts. Compared with the control group, when IGF-1 at the concentration of 10 ng·mL^-1, the expression level of KGF was 3.332 times and IGF-1R expression level was 4.479 times. TGF-β1 gene expression level was the lowest, 0.405 times at 10 ng·mL^-1,0.813 times at 1 ng·mL^-1 and 0.434 times at 100 ng·mL^-1. The results indicate that alpaca skin fibroblasts are the target organ of IGF-1,as well as endocrinal organ.IGF-1 can induce the proliferation of alpaca skin fibroblasts, while improving expression level of IGF-1R and KGF genes, reducing the expression of TGF-β1 gene, which indicate that IGF-1 can modulate the growth and development of alpaca hair by regulating the expression of its receptor and endocrine factors.