Abstract
Purpose: :
To determine the impact of grape seed extract (GSE) on canine lens epithelial cells (LEC) following exposure to ultraviolet (UV) radiation.
Methods: :
Primary cultures of canine LEC (n=4) were pretreated with 0 or 50 µg/mL GSE prior to UV exposure (300 J/m2), and allowed to recover. In concurrent experiments, cultured LEC (n=4) were UV irradiated and allowed to recover the presence of GSE (doses ranging from 0 - 50 µg/mL). Cell viability in all treatment groups was assessed via MTT assay. To evaluate LEC apoptosis, a cytochrome c release assay and a caspase-3 activity assay were used. Immunoblot analysis was performed to evaluate the expression of phosphorylated JNK (pJNK) in LEC following UV and GSE treatments. Nonparametric statistical tests were used to compare outcomes accounting for treatment group and UV exposure status.
Results: :
Both LEC pretreated with GSE prior to UV irradiation and LEC allowed to recover from UV exposure in the presence of GSE, demonstrated a significant increase in cell viability compared to controls (p<0.05). Following irradiation, apoptosis in LEC was increased; treatment with GSE significantly (p=0.002) reduced UV-induced LEC apoptosis. In addition, GSE was able to significantly (p=0.002) lower pJNK protein expression relative to irradiated control LEC, in which pJNK expression was increased.
Conclusions: :
GSE was capable of reducing UV induced LEC apoptosis, potentially through the pJNK signaling pathway. In combination with previous data, there is evidence that GSE could potentially protect LEC from the damaging effects of UV and subsequent oxidative stress.
Keywords: antioxidants • apoptosis/cell death • oxidation/oxidative or free radical damage