Study On Expression Of VEGF MRNA In Hair Follicles Cycling Of Liaoning Cashmere Goats

Liaoning cashmere goats originate from Liaodong Peninsula,and mainly distribute in Gaizhou and its adjacent regions,such as Youyan,Liaoyang,Benxi,Fengcheng,Kuandian,Zhuanghe,and Wafangdian.The cashmere yield of Liaoning cashmere goats is about 1860g,and it is the highest.Liaoning cashmere goat is famous for its fine cashmere quality,large body,high cashmere yield,well adaptability,and stable genetic character.Through systematic breeding of 30 years from 1980s,now there have been two lines of perennial and seasonal cashmere types.The cashmere wool is high-grade textile materials,and generated from secondary follicles.The structures of skin and hair follicle have important effect on the cashmere yield and quality.The reconstruction of hair follicles start from the connection between epithelial cells and mesenchymal cells,and the secondary follicles appears with group during this process.The thickness of epidermis show periodic change.The depth, density,and S/P of hair follicle and the width,and growth speed of hair bulb are main factors which affect the cashmere yield.Recent years,associating with increasing of cashmere price,the amount of cashmere goats are also increasing year by year,but overgrazing causes severe damage of vegetation.How to improve the cashmere yield,reduce the number of cashmere goats,and understand the molecular mechanism and so on are getting more attention of government and researchers.So,the further study on skin structure,the histology endocrinology,and molecular mechanism of cashmere is helpful to explain the regulatory mechanism and improve breed.4 ewes were selected from nucleus herd in breeding center of Liaoning cashmere goats in Liaoning province.The skin on right side of scapular trailing edge,the 1/3 of connection between center line on back and center line on abdomen were sampled from 20^th to 23^rd on October and December in 2006,February, April,June,and August in 2007.HE staining was used and thicknesses of epidermis and dermis,depths, densities,bulb width,and S/P ratio of primary and secondary follicles were observed and counted.The morphology change law of hair follicles was studied within one year.The results showed that,the anagen was from April to October,catagen was from Noveber to December,and telogen was from January to March,and they lasted seven,two,and three months,respectively.The anagen was longest and catagen was shortest.But in catagen,most of hair follicles were highly active,the cashmere was still growing,especially during earlier tage(October and Noveber). RT-PCR technique was used to study the relative expression of VEGF in the follicles of two lines of perennial and seasonal cashmere types.Total RNA isolation method from the skin of cashmere goats was studied,and then the total RNA was used as template to amplify the VEGF gene,and its relative expression was determined.The results showed that VEGF expressed in the follicles of both two lines,and the differential expression between two lines was not significant(P＞0.05).But VEGF expression level was highest in February,and there was significant difference compared to other months(P＜0.05).The VEGF expression level maintained highly all around year,besides in February.It may explain why perennial type can make cashmere perennially.