EŠects of Protein Deprivation on a1(I) and a1(III) Collagen and Its Degrading System in Rat Skin

Protein malnutrition aŠects the status of dermal collagen, the major structural protein in the skin. However, the molecular mechanism underlying the alteration of collagen ˆbers in the skin by protein deˆciency remains unknown. In the present study, the eŠect of dietary protein deprivation on collagen metabolism was studied by analyzing the status of the synthesis and degradation of collagen in the dorsal skin of rats. Feeding on a protein-free diet for 8 days caused a dramatic decrease in both types I and III tropocollagen with a concomitant decrease in their mRNA levels, with type III collagen being more severely aŠected. The active form of collagenase was signiˆcantly decreased by protein deprivation, whereas the latent form was not aŠected. The mRNA levels of collagenase and its inhibitors (TIMP-1 and 2) were also decreased by protein deprivation. These results suggest that both the synthesis and degradation of types I and III collagen were aŠected by protein deˆciency.