Proliferative, anti-apoptotic and immune-enhancing effects of L-arginine in culture of skin fibroblasts

Semi-essential amino acid L-arginine may be of fundamental importance in various intracellular and intercellular pathways related to skin repair and wound healing. Our current study was aimed to explore the effect of L-arginine on skin fibroblast (L929) signaling pathways involved in cell proliferation (Akt-pAkt kinase, Erk/pErk1/2 kinase, JNK/pJNK kinase and pStat-1), apoptosis (Bcl2 and Bax) and immune defense (NF-κB and CD26). Significant upregulation of Erk (p<0.011), pErk (p<0.017) and JNK (p<0.002) was documented, while the rise was not significant for pJNK kinase. The Akt/pAkt signaling pathway did not change significantly for the above-mentioned time and dose, while pStat-1 was significantly down regulated (p<0.011). The exposure of skin fibroblasts to L-arginine increased anti-apoptotic Bcl2/Bax stoichiometry ratio (p<0.05), obtained by calculation of their individual quantities. L-arginine was able to elicit NF-κB signaling through the increase of p65 active subunit level (p<0.004), while CD26 surface antigen level was not significantly changed. In conclusion, the exposure of skin fibroblasts to L-arginine may help in maintaining and stimulating skin fibroblast proliferative, anti-apoptotic and immune defense function. Therefore, the proposed L-arginine dose may be used for tissue regeneration application, which would be of importance in regenerative medicine, skin rejuvenation approaches and wound healing.