Insulin catalyzes the curcumin-induced wound healing: An in vitro model for gingival repair

OBJECTIVES: Human gingival fibroblasts (hGFs) play a major role in the maintenance and repair of gingival connective tissue. The mitogen insulin with IGFs etc. synergizes in facilitating wound repair. Although curcumin (CUR) and insulin regulate apoptosis, their impact as a combination on hGF in wound repair remains unknown. Our study consists of: 1) analysis of insulin-mediated mitogenesis on CUR-treated hGF cells, and 2) development of an in vitro model of wound healing. MATERIALS AND METHODS: Apoptotic rate in CUR-treated hGF cells with and without insulin was observed by AnnexinV/PI staining, nuclear morphological analysis, FACS and DNA fragmentation studies. Using hGF confluent cultures, wounds were mechanically created in vitro and incubated with the ligands for 48 h in 0.2% fetal bovine serum DMEM. RESULTS: CUR alone showed dose-dependent (1-50 μM) effects on hGF. Insulin (1 μg/ml) supplementation substantially enhanced cell survival through up-regulation of mitogenesis/anti-apoptotic elements. CONCLUSIONS: The in vitro model for gingival wound healing establishes that insulin significantly enhanced wound filling faster than CUR-treated hGF cells over 48 h. This reinforces the pivotal role of insulin in supporting CUR-mediated wound repair. The findings have significant bearing in metabolic dysfunctions, e.g. diabetes, atherosclerosis, etc., especially under Indian situations.