Study On Different Hair Types Of Inner Mongolia Cashmere Goat In Periodic Changes Of Skin And Hair Follicles And Related Molecular Mechanisms

Inner Mongolia Cashmere goat is a cashmere-producing goat and the cashmere is a precious textile material because of its soft fibers,good gloss,light and comfortable products.Therefore,cashmere is known as "soft gold" and "fiber gemstone".Previous analysis depended on production performance records and hair and cashmere quality records of Inner Mongolia Cashmere goats showed that hair length had a significant impact on other important economic traits of Inner Mongolia Cashmere goats.According to Inner Mongolia Cashmere goat's hair type,the analysis results showed that Inner Mongolia Cashmere could be divided into short hair type,middle hair type and long hair type.Reserving long-hair individuals for seed use can accelerate the genetic progress of many economic traits of cashmere goats,and further realize the objective of indirect selection of other important economic traits by hair length.Based on the previous research results,we selected long-hair type and short-hair type Inner Mongolia Cashmere goats(Aerbas type)to explore the regulation mechanism of the variation of different hair types of Inner Mongolian Cashmere goats' skin and hair follicle from the level of apparent traits,transcriptome and histomorphology et al.The main conclusions are as follows:1.Measuring the growth length of hair and cashmere in each month,we found that the hair and cashmere did not grow from March to May,the old cashmere fell off in May;the hair began to grow in June and cashmere could be observed from skin in July.September was the month that hair growth longest of two hair type cashmere goats and gain the most difference between two hair types,this may conclude that September was an important period affecting the difference in the length of cashmere between the two hair types;November and December were the longest month for cashmere growth while short-hair cashmere goat was November and long-hair cashmere goat was December.2.To make paraffin sections of skin tissue of long-hair type cashmere goats and short-hair type cashmere goats for 12 months,stain with Sacpic method and observe them under microscope.The results showed that the growth cycle of secondary follicles in Inner Mongolia Cashmere goats could be divided into three stages:anagen(April to November),catagen(December to January of the next year)and tclogen(February to March).There was no difference in skin structure and composition between two hair types cashmere goats.However,the active S/P(active secondary hair follicle/primary hair follicle)value of long-hair type cashmere goats was significantly lower than that of short-hair type cashmere goats from August to October in growth period;the active S/P value of long-hair type cashmere goats was significantly higher than that of short-hair type cashmere goats from late anagen to catagen;the secondary follicle density of long-hair type cashmere goats was significantly higher than that of short-hair type cashmere goats from August to September in anagen.Heredity is the main factor affecting different hair type of Inner Mongolia Cashmere goats.3.We extracted total RNA from skin tissue of two hair types cashmere goats for 12 months and sequenced by transcriptome on Illumina X Ten sequencing platform.A total of 550.73G filtered bases were obtained and 31379 transcripts were annotated.There were 448 different expression genes(DEGs)between two hair types cashmere goat in each month and 108 repeated DEGs.4.The GO enrichment analysis showed that the biological processes of DEGs were mainly enriched in protein import into nucleus,protein targeting to nucleus,protein localization to nucleus,lipid metabolic process;the main cellular components of DEGs were mainly enriched in intermediate filament,intermediate filament cytoskeleton,cytoskeletal part;and the molecular functions were mainly concentrated in dynein binding,protein homodimerization activity,identical protein binding etc.KEGG pathway enrichment results showed that DEGs were mainly concentrated in the biosynthesis of unsaturated fatty acids,fatty acid metabolism,alpha-linolenic acid metabolism and PPAR signaling pathways.5.Through differential expression analysis,GO and KEGG enrichment analysis,five DEGs were found:LOC108637647,LOC108635030,LOC108633182,Nove102382 and SCD,which may be related to the variation of different hair types of cashmere goats.The relative expression of LOC108637647,LOC108635030,LOC108633182 and Nove102382 in short-hair cashmere goats was higher than that in long-hair cashmere goats.It could conclude that LOC108637647,LOC108635030,LOC108633182,Nove102382 and SCD were the important influence factors of different hair types of cashmere goats.6.The expression of SCD1 in skin follicles was determined by immunohistochemical.The results showed that SCD1 was mainly expressed in root sheath of primary hair follicle,hair stem of secondary hair follicle,subcutaneous adipose tissue and dermal papillary layer in the skin tissues of two hair types cashmere goats in September while a little expressed in connective tissue sheath of primary hair follicle.In December,SCD1 protein was mainly expressed in root sheath of primary hair follicles,hair stem of secondary hair follicles and subcutaneous adipose tissue of two hair types cashmere goats,but no positive signal was found in dermal papillary layer.In March,SCD1 was mainly expressed in subcutaneous adipose tissue of two hair types cashmere goats,and expressed a little in root sheath and connective tissue sheath of primary hair follicles and hair stem of secondary hair follicle.