Figure 5
Elevated nitric oxide level produced by mesenchymal stem cells with p53 deficiency may be responsible for the proliferation promotion of hypotrophic scar fibroblasts. Mesenchymal stem cells (MSCs) with or without p53 knockdown were treated with or without interferon gamma (IFNγ) and tumor necrosis factor alpha (TNFα) (10 ng/ml each) for 24 hours. (A) Inducible nitric oxide synthase (iNOS) mRNA was measured by real-time PCR. (B) Total nitrate was measured by Griess. (C) Conditioned medium from MSCs treated with IFNγ and TNFα for 24 hours was added to cultured hypertrophic scar fibroblasts with or without treatment with 1 mM NG-monomethyl-l-arginine acetate salt (L-NMMA). Cells were trypsinized and counted 48 hours later on the indicated days. n = 3, *P <0.05 vs. p53 shRNA group. Data shown are representative of three individual experiments. Ctrl, control.