Morphogenesis Of Eyelash Follicle And Construction Of Anagen Dermal Papilla CDNA Library In Bovine Eyelash Follicle

Hair follicle is complex and dynamic organ for growing hair shaft , which make up of multicell including the epidermal cells in differentiating phase and the mesenchyma cells. The dermal papilla of hair follicle is designated"central oscillators"of"hair cycle clock", these specialized mesenchyma cells play a key role in hair follicle morphogenesis and regulation of hair cycle. Wnt/β-catenin signaling pathway is critical for both inducing hair follicle morphogenesis and maintaining proliferation and differentiation of the stem cell in hair cycle. The slower growth of eyelash result from the eyelash hair follicle very short anagen and longer telogen,so eyelash follicle is a kind of special hair follicle. The diameter of eyelash is determined by dermal papilla size. Few paper can be found on eyelsh follicle research as yet.Our study on the eyelash follicle morphogenesis and the mechanism of the dermal papilla in control of the hair cycle in bovine is important and significative not only for understanding the molecular mechanism of epithelia-mesenchyma interaction but also elucidating of regeneration of the tissue and the organs as well.We use bovine embryonic eyelids as experimental material firstly to study eyelash follicle morphogenesis and detect the expression ofβ-catenin qualitatively by immunohistochemical method of paraffin section .The construction of anagen dermal papilla cDNA expression library in neonatal bovine eyelash follicle is a basis of further research on eyelash dermal papilla. The result and conclusion are as follows:1. Morphogenesis of the eyelash follicle is similar to other peripheral follicle but earlier than them.The placode and the hair bud of eyelash follicle emerged during embryonic age week 12～14; The hair peg shaped primarily during E week14～16 and was going on during E week 16～20; The hair follicle completed during E week 24～28 eventually. The mature eyelash follicle has larger diameter of dermal papilla and abundant sebaceous gland than the peripheral follicle in bovine embryos .2. Our results suggest thatβ-catenin may plays an important role in the eyelash follicle placode patterning and differentiating of hair follicle stem cell.β-catenin is detected in the placode, the hair bud and the hair peg during the early( E week 12～14) and middle phase (E week 14～20) of bovine eyelash follicle development, the bulge and the matrix are strongly positive ; the bulge , the outer and inner root sheath close to the bulge are strongly positive while expression ofβ-catenin in the matrix decrease during the late phase of eyelash follicle development(E week 20～24) and maturing phase (E week 24～28) .3. The construction of anagen dermal papilla cDNA library in neonatal Hostein cattle eyelash follicle are successful and first in world. Detection results shows that capability of the primary library and secondary library are 2.3×105pfu/mL and 3.3×107 pfu/mL respectively;The recombination rate is 95%(>80%) and the tittering is larger than 105.These result indicate that the high quality library has been constructed and lay the research foundation of cDNA microarray-based screening of differentially expressed genes on anagen dermal papilla and elucidating the molecular mechanism of gene expression regulation during the eyelash follicle morphogenesis .