[Effect of curcumin on TGF-β1 /Smad3 pathway in rat gingival fibroblast treated with cyclosporine A]

The aim of the present study was to investigate the effect of curcumin (Cur) on TGF-β1/Smad3 pathway of rat gingival fibroblast treated with cyclosporine A (CsA) in vitro, and to provide theoretical basis for the mechanism of curcumin inhibiting drug-induced gingival hyperplasia induced by CsA.

Healthy Sprague-Dawley rat gingival fibroblasts were cultured with different concentrations of Cur (0, 5, 10, 20, 30 μmol/L) and Cur (20 μmol/L)+CsA(200 ng/mL), cell proliferation was assessed with CCK-8 assay. The mRNA levels of TGF-β1, Smad3, α-SMA and collagen type Ⅰ in gingival fibroblasts were detected by real-time PCR under Cur(20 μmol/L)+CsA(200 ng/mL); the protein level of TGF-β1, Smad3, p-Smad3, α-SMA and collagen type Ⅰ were determined through Western blot. The effect of Cur(20 μmol/L)+CsA(200 ng/mL) on migration ability of gingival fibroblasts was observed through Scratch wound-healing assay. The data were analyzed with SPSS 23.0 software package.

Cell proliferation and migration ability of rats gingival fibroblasts were significantly reduced under Cur(20 μmol/L)+CsA(200 ng/mL). 20 μmol/L Cur significantly decreased mRNA expression of TGF-β1, α-SMA and collagen type Ⅰ in gingival fibroblasts, and Western blot suggested significantly down-regulated expression of TGF-β1, p-Smad3, α-SMA, and collagen typeⅠ.

Cur may inhibit TGF-β1/Smad3 signaling pathway of gingival fibroblasts activated by CsA, thereby weakening proliferation and migration, reducing secretion of smooth muscle actin and collagen of gingival fibroblasts, and ameliorating gingival hyperplasia.