Anti-Inflammatory and Pro-apoptotic Effects of Curcumin and Resveratrol on the Human Lung Fibroblast Cell Line MRC-5

Abstract

Background: The naturally occuring polyphenols curcumin and resveratrol are considered to be powerful antioxidants and anti-inflammatory compounds and both inhibit the proliferation of different types of cancer cells. In the present study, we investigated possible anti-inflammatory and pro-apoptotic effects of curcumin and resveratrol on the human lung fibroblast cell line MRC-5. Methods: MRC-5 cells were stimulated for 6 h with interleukin (IL)-1β or phorbol 12- myristate 13-acetate (PMA) in the absence or presence of different concentrations of curcumin or resveratrol. The release of interleukin (IL)-6 was quantified by enzyme-linked immunosorbent assay (ELISA). The modulation in phosphorylation of the transcription factor nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) such as p38 and ERK1/2 were analyzed by Western blot. Cytotoxic and pro-apoptotic effects of curcumin and resveratrol were monitored by the measurement of lactate dehydrogenase (LDH) activity and by Annexin-V/7-AAD staining. Results: Both curcumin and resveratrol effectively attenuated IL-1β and PMA-induced IL-6 expression in MRC-5 cells. Furthermore, curcumin treatment induced apoptosis via caspase-3 signaling and caused endoplasmic reticulum (ER) stress. Salubrinal, an inhibitor of serine/threonine phosphatase PP1, and antioxidants such as N-acetyl-cysteine (NAC), reduced glutathione (GSH) and sodium hydrogen sulfide (NaHS) diminished the cytotoxic effects of curcumin on MRC-5 cells. In contrast to curcumin, resveratrol had no negative effects on cell viability