comprehensive analysis of zinc derivatives pro-proliferative, anti-apoptotic and antimicrobial effect on human fibroblasts and keratinocytes in a simulated, nutrient-deficient environment in vitro

Zinc as therapeutic agent in skin and wound care has been known for centuries, but its role is controversial and comprehensive investigations in nutrient-deficient environments are lacking. we aimed to provide a broad analysis of different zinc derivatives on proliferation, apoptosis and antimicrobial properties in a simulated nutrient-deficient environment in vitro. human fibroblasts (crl2522) and keratinocytes (hacat) were treated with a broad concentration range (10 – 0.0001 μg/ml) of zinc-sulfate (znso4), -gluconate (zngluc) and -histidine (znhis) for 1-6 days under nutrient-deficient media conditions. cell proliferation was investigated by xtt assay. targeted analyzes in proliferation (e2f1, pcna) and apoptosis (tp53) associated genes were performed via qrt-pcr and apoptosis was determined via facs (annexin v/7-aad staining). antimicrobial efficacy was investigated using a quantitative suspension method against s. aureus, p. aeruginosa, e. coli, and c. albicans. the results indicated that 0.1 to 0.001 μg/ml zn increased cell proliferation in both cell lines. fibroblasts were more susceptible with significant proliferation peaks on days 2 & 6, and days 1 & 4 for keratinocytes. no relevant changes in gene expression were detected for e2f1 and pcna nor for tp53. annexin-v/7-aad-staining of fibroblasts revealed a small, yet insignificant reduction of apoptosis induction for zngluc and znso4. zngluc and znso4 (0.1%) achieved high microbial reductions (4-5 log10 reductions) against tested pathogens. zngluc and znso4 showed relevant pro-proliferative and antimicrobial, as well as tendential anti-apoptotic features in a simulated nutrient-deficient microenvironment in vitro. this further validates a potential benefit of local zinc treatment in deficient wound microenvironments.