Protective effect of trans-resveratrol on dexamethasone-induced changes in matrix metalloproteinases expression by human potential mechanisms

• Main Author: Normie Aida Mohd Nasir (Author)
• Format: Thesis Book
• Language: English
• Published: Sungai Buloh, Selangor Universiti Teknologi MARA. Faculty of Medicine 2019
• Subjects: Polyphenols > therapeutic use; Dexamethasone; Metalloproteases; Trabecular Meshwork
• Online Access: Click Here to View Status and Holdings.
• Item Description: UiTM Digitized
• Physical Description: xviii, 183 pages illustrations (some color), charts 30 cm
• Bibliography: Includes bibliographical references (page 131-167)

Matrix metalloproteinases (MMPs) can regulate extracellular matrix (ECM) turnover in the trabecular meshwork (TM) of eye. Reduced MMP secretion increases ECM deposition in TM, which is associated with increased intraocular pressure (IOP). Increased IOP is the major risk factor for glaucoma, the leading cause of irreversible blindness, worldwide. Previously trans-resveratrol was shown to reduce IOP in normotensive and oculohypertensive rats. The dose- and time-dependent effects of trans-resveratrol on human TM cells (HTMCs) viability, MMP-2 and -9 secretion and the mechanisms involved remain unknown and hence these effects were investigated in the present study. HTMCs were cultured and divided into 11 groups that received treatment with DMSO (0.1%), dexamethasone (100 nM), and trans-resveratrol (3.125, 6.25, 12.5, 25 and 50 uM) either in the presence or absence of dexamethasone for 2, 5 and 7 days. To study the role of Aj adenosine receptors (AJAR) and nuclear factor kappa B (NFKB) in trans-resveratrol mediated effects on MMP secretions, additional groups of HTMCs were pre-treated with dipropylcyclopentylxanthine (DPCPX), a specific AjAR antagonist and curcumin, an inhibitor of NFkB. Cell viability was determined by using MTS assay while MMP-2 and -9 expressions were investigated using western blot. AjAR expression was determined using western blot and ELISA while NFkB activation was determined using immunocytochemistry and ELISA. This study demonstrated that incubation of HTMCs with trans-resveratrol up to a concentration of 25 um does not affect the viability but at 50 uM, it significantly reduces viability of HTMCs both in the presence and absence of dexamethasone. This effect of trans-resveratrol on the viability of HTMCs was dose-dependent but not time-dependent. Dexamethasone reduced MMP-2 and -9 expressions after 5- and 7-days treatment, compared to untreated group (p<0.01). Incubation with 12.5 uM trans-resveratrol for 5 days in the presence of dexamethasone increased MMP-2 and - 9 level compared to dexamethasone-treated group (p<0.05). Significant reduction of AJAR expression was seen in dexamethasone-treated group compared to untreated group (p<0.01). Trans-resveratrol significantly increased AjAR expression compared to dexamethasone treated and DPCPX-treated groups (p<0.001). Dexamethasone significantly reduced NFkB activation compared to the untreated group (p<0.001). Increased nuclear localization of phospho p65 NFkB was seen in trans-resveratrol treated group in the presence and absence of dexamethasone. In conclusion, trans- resveratrol counteracts the effects of dexamethasone on MMP-2 and -9 levels of HTMCs, which could be mediated by AjAR and NFkB