Effects of early and later hUC-MSC injections on systemic levels of pro-inflammatory and pro-fibrotic cytokines Serum concentrations of the pro-inflammatory cytokines IL-6 and TNF-α and the pro-fibrotic cytokine TGF-β1 were compared for Non-DM, DM + NS and DM + hUC-MSC groups for the in vivo experiments of 10 weeks and 18 weeks duration (Fig. 7). The gene discussed is IL6; the disease is diabetes mellitus.