The Molecular Mechanism Of Melatonin Affectting The Growth Of Cashmere

The paper studies the implanting melatonin (MT) of Cashmere goats in Inner Mongolia. The changes in production characters and the expression level of growth related gene in skin were studied for three treatments:implanted MT for two consecutive years, implanting MT for1year and stopped implant MT. The analysis results could provide references and basis for the molecular mechanism of Cashmere growth research, and establish the theoretical foundation for the actual production practice of MT. To study the effect of MT on the Cashmere growth traits and the quality of Cashmere, diameter and length of Cashmere and wool were measured monthly; at the same time, study on the influence of implanting MT on the expression level of growth related gene in skin using the RT-PCR and in-situ hybridization techniques. Those results suggested that:The implanting MT shortened the time of Cashmere growth cycle. Starting to implant MT from July, the Cashmere goats depilated Cashmere twice in one year, and four times during two years after implanting MT another year. Stopped implanting MT after the first one year, the Cashmere goats depilated Cashmere three times during two years and delayed depilation in next spring. Although the depilated Cashmere in autumn was shorter than in spring, the length of Cashmere can meet the requirement of production. Implanting MT or stopped implanting had no effect on Cashmere thickness, length and diameter of mature goats in spring; implanting MT for two consecutive years to lamb can decrease the Cashmere diameter. Stopped implanting after one year treatment for lamb made the Cashmere length getting shorter. Implanting MT had no effect on wool length and growth cycle, but decreased the tendency of wool diameter for one year old Cashmere goat in implanting year. The proportion of cashmere and wool had been significantly declined by consecutive implanting MT for two years in lamb, had been improved by implanting MT in mature goat. The Cashmere field improved in the first year of implanting MT, and decreased in the next year after implanting MT for two consecutive years; the Cashmere field had similar trend to control group after stopping implanting MT for Cashmere goat.RT-PCR results showed:In the mature goat skin, the expression levels of TGFβ2, Deltal, Notch1, Wnt10b, MSX-2, p-catenin, FGF5, PDGFA, PDGFRa and RORa had increased during Propagate anagen; TGFβ2, TGFβRâ…¡, Notch1, hairless, Wnt10b, P-catenin, PDGFA, NTRK3, RORa, RORPβå'ŒRORγ had decreased on fast growing stage of Cashmeres; BMPR1B, TGFβ2, Notch1, hairless, Wnt10b, β-catenin, PDGFA, NTRK3, RORα, RORβ and RORγ had decreased in catagen and refractory telogen; BMP2and Delta1had decreased in refractory telogen after increased in telegon; BMP2, TGFβRâ…¡, PDGFA:NTRK3, RORa, RORβ and RORγ had highest in categon.It may related to promote hair follicle cycle in the categon, that Wnt10b gene expression level in mature goat skin was decreased after stopped implanting MT or consecutive implanting MT for two years in Cashmere fast growing stage and refractory telogen. However, implanting MT for1or2years increased the expression level of Wnt10b and decreased the expression level of BMP2in telogen, which induced hair follicle growth initiate earlier. Implanting MT influence the expression of Wnt10b by affecting the expression of RORy gene, this decreased the relativity between Wnt10b and RORy gene, further influence the expression of other signal pathway molecular. In contrast with control group, implanting MT decrease the expression level of RORa, RORP and RORy gene in catagen and telogen, β-catenin gene in refractory telogen and NTRK3gene in telogen, however increased the expression level of MSX-2and FGF5gene. The expression levels of TGFβRâ…¡, NTRK3, Delta1and RORa gene decreased in hair fast growing stage by stopped implanting MT, but the expression level of TGFβRâ…¡ and BMPR1B gene in competent telogen was decreased. For the consecutive implanting MT group, the expression level of BMP2gene in anagen and the expression level of TGFβRâ…¡ gene in telogen were decreased; however increased the expression level of BMPR1B, Notch1and hairless gene in refractory telogen. The expression level of BMP2gene in cetagon and the expression level of TGFβRâ…¡ gene in telogon were decreased by implanting MT from july to mature goat. Wnt10b, PDGFA and RORa gene were related to hair follicle growth cycle which was influenced by implanting MT. The expression level of WntlOb, PDGFA and RORa gene were changed with hair follicle cycle. In the skin, the other signal pathways were regulated by TGFβ signal pathway which through WNT signals.The results of In Situ Hybridization indicated that there was the same expression pattern for BMP2mRNA on the two kind of hair follicle; While BMP2was expressed on Outer Root Sheath and Connective Tissue Sheath over year after implanting MT. Wnt10b mRNA was detected one month earlier on Outer Root Sheath and two months earlier on Connective Tissue Sheath for Secondary hair follicle after fleecing for implanting group than control group.