Quercetin protects HCT116 cells from Dichlorvos-induced oxidative stress and apoptosis

Abstract

The present study was designed to assess the possible protective effects of Quercetin (QUER), a flavonoid with well-known pharmacological effects, against Dichlorvos (DDVP)-induced toxicity in vitro using HCT116 cells. The cytotoxicity was monitored by cell viability, reactive oxygen species (ROS) generation, anti-oxidant enzyme activities, malondialdehyde (MDA) production, and DNA fragmentation. The apoptosis was assessed through the measurement of the mitochondrial transmembrane potential (ΔΨm) and caspase activation. The results indicated that pretreatment of HCT116 cells with QUER, 2 h prior to DDVP exposure, significantly decreased the DDVP-induced cell death, inhibited the ROS generation, modulated the activities of catalase (CAT) and superoxide dismutase (SOD), and reduced the MDA level. The reductions in mitochondrial membrane potential, DNA fragmentation, and caspase activation were also attenuated by QUER. These findings suggest that dietary QUER can protect HCT116 cells against DDVP-induced oxidative stress and apoptosis.

Fig. 1

a Cytotoxic effect of DDVP and QUER on HCT116 cells. Cells were treated with DDVP or QUER at the indicated concentrations for 24 h. Cell viability was determined using the MTT assay and expressed as percentages of viability. Values are significantly different (P < 0.05) from control. b Quercetin reduces DDVP-induced cytotoxicity in HCT116. Cells were pretreated for 2 h with QUER (5, 10, and 25 μM) before DDVP treatment for 24 h (300 μM). Data are expressed as the mean ± SD of three independent experiments. **P < 0.01 vs. DDVP alone

Fig. 2

Effects of Quercetin on DDVP-induced ROS generation. HCT116 cells were pretreated with QUER (5, 10, and 25 μM) for 2 h before DDVP treatment for 24 h (300 μM). The relative intracellular ROS production was evaluated by recording the fluorescence of DCF, the product of DCFH oxidation mainly by H₂O₂. Data are expressed as the mean ± SD of three separate experiments. ##P < 0.01 vs. control, ***P < 0.001 vs. DDVP alone

Fig. 3

Effects of Quercetin on superoxide dismutase (a) and catalase (b) activities. HCT116 cells were pretreated with QUER (5, 10, and 25 μM) for 2 h before DDVP treatment for 24 h (300 μM). Data are expressed as the mean ± SD of three separate experiments. ###P < 0.001 vs. control, **P < 0.01 and *P < 0.05 vs. DDVP alone

Fig. 4

Effects of Quercetin on DDVP-induced lipid peroxidation. HCT116 cells were pretreated with QUER (5, 10, and 25 μM) for 2 h before DDVP treatment for 24 h (300 μM). The peroxidation of lipids was recorded by measuring the accumulation of MDA. Data are expressed as the mean ± SD of three separate experiments. ###P < 0.001 vs. control, **P < 0.01 and ***P < 0.001 vs. DDVP alone

Fig. 5

Effects of Quercetin on DDVP-induced loss of mitochondrial transmembrane potential. HCT116 cells were pretreated with QUER (5, 10, and 25 μM) for 2 h before DDVP treatment for 24 h (300 μM). The mitochondrial potential was assessed by measuring the uptake of rhodamine-123. Data are expressed as the mean ± SD of three separate experiments. ##P < 0.01 vs. control, **P < 0.01 vs. DDVP alone

Fig. 6

a Effects of Quercetin on DDVP-induced caspase-3 activation. b Effects of Quercetin on DDVP-induced DNA damage. HCT116 cells were pretreated with QUER (5, 10, and 25 μM) for 2 h before DDVP treatment for 24 h (300 μM). Data are expressed as the mean ± SD of three separate experiments. ###P < 0.001 vs. control, *P < 0.05 and **P < 0.01 vs. DDVP alone