OCCURRENCE AND LOCALIZATION OF TRANSFORMING GROWTH-FACTOR-BETA (TGF-BETA-1, BETA-2) DURING RABBIT SKIN DEVELOPMENT

The expression of (TGFbeta-1) and (TGFbeta-2) in adult, fetal, and neo natal rabbit skin has been analyzed by immunohistochemistry. Samples w ere collected from the backs of fetal rabbits (23 and 30 days of gesta tion), newborn rabbits (1 day post-partum) and adult pregnant and nonp regnant rabbits. Forty samples were studied. To identify TGF-beta two antibodies were used: (RAB4) and (CL-B1/29). TGF-beta1 and TGF-beta2 d isplayed distinct distribution and intensity of staining at different stages of development. TGF-beta1 was present in fetal skin (23 days of pregnancy) expressing abundant staining in cells within epidermis, de rmis and hypodermis. Fetal skin (30 days of pregnancy) exhibited weak staining for TGF-beta1; only isolated dermal cells in close proximity to hair follicles and sweat glands expressed intracellular staining. N ewborn rabbit skin showed low expression for TGF-beta1, around hair fo llicles and sweat glands. In contrast adult pregnant and non-pregnant rabbit skin exhibited abundant staining for TGF-beta1 in epidermis, pa pillary dermis, around hair follicles, sweat glands, and blood vessels , no difference was observed among pregnant and non-pregnant rabbits. TGF-beta2 was detected in all specimens and the distribution and inten sity of staining were similar to those found for TGF-beta1 in all grou ps. Our findings demonstrate that the expression of TGF-beta1 and TGF- beta2 is intense during early stages of rabbit skin development when m orphogenesis is taking place and skin appendages are being formed; and less intense when these structures are formed and skin growth predomi nates. These results suggest an important role for TGF-beta1 and TGF-b eta2 in rabbit skin development, probably regulating morphogenesis and growth.