Effects of growth factors and L-arginine on ischemic skin flaps in rats

This study determined the effect of the polypeptide growth factors transforming growth factor-beta (TGF-beta), insulin-like growth factor-I (IGF-I), and growth hormone (GH) alone and in combination with dietary L-Arginine HCL (ARG) on skin flap survival in rats. Caudally based dorsal skin flaps were created in 110 Sprague-Dawley rats. The rats were randomly assigned into three treatment groups, based on drinking water supplementation. Group 1 (n = 50) received ARG in their drinking water, group 2 (n = 50) received tap water alone, and group 3 (n = 10) received N-omega-nitro-L-arginine (L-NA) and hydralazine. Groups 1 and 2 were divided into subgroups of 10 rats each based on treatment with either: TGF-beta, IGF-I, GH, or IGF-I + GH. All subgroups that received GH had significantly greater (P < .0001) median body weight gains when compared with subgroups not receiving GH. L-arginine HCL when added to IGF-I negated the positive effects of IGF-I on both flap survival and weight gain. Although the rats in all subgroups from groups 1 and 2 had an increase in mean percent skin flap survival when compared with the water alone subgroup, only rats receiving IGF-I, or the combination of ARG with either TGF-beta or GH, had statistically significant enhanced skin flap survival. Rats in group 3 did not show an increase in skin flap survival when compared with the control subgroup.