23.    Comparison of mRNA expression in hair follicles of hairless with normal rats.
Satoru Tani, Pharmacology, Josai University, Japan

[Introduction] The hairless rat is a mutant of the Wistar rats with short, fine and scattered hairs. Now many hair growth factors were reported. We compared the expression of hair growth factorfs mRNAs in hair follicles of hairless with normal rats. [Methods] RT-PCR was performed using extract of RNA from hair follicle of hairless and normal Wistar rats. Real time PCR was carried out for the quantitative measurement of the mRNA. [Results] Amounts of BMP3-, BMP7-, TGF beta-, IGF1-, IGF2-, and EGF-mRNA in hair follicles were almost equal in hairless and normal rats. However, BMP receptor IA is less expressed in hairless rats than normal rats. Amount of IGF1 and IGF2 receptor-mRNA were almost equal in both rats. HGF-, FGF5-, VEGF- and ephrin A3 receptor-mRNAs were not detected. Beta-actin was less expressed in hair follicles of hairless rat. Amounts of BMP receptor IA-mRNA in bone were equal in hairless and normal rats. Also, amounts of beta-actin-mRNA in the dermal tissue were almost equal. These results suggested that BMP receptor IA and beta-actin were less expressed in hair follicles of hairless rat specifically.
Quantitative analysis by real time PCR, amounts of BMP receptor IA-mRNA and beta-actin were about 1/3 and 1/2, respectively. [Discussion] It was reported that the hair follicle and IRS were reduced in BMP receptor IA KO mice. These results show BMP receptor IA was one of important factors on hair growth. At the same time, a specific function of beta-actin in hair growth is presumed. [Conclusion] Hairless rat is a useful animal for the development of hair restorations, e.g. a stimulator of BMP receptor IA or beta-actin in hair follicles might be a kind of hair restorations.