Gelam Honey Protects against Gamma-Irradiation Damage to Antioxidant Enzymes in Human Diploid Fibroblasts

Tengku Ahmad,Suzana Makpol,Zakiah Jubri,Khairuddin Rahim,Yasmin Yusof,Nor Rajab

doi:10.3390/molecules18022200

Tengku Ahmad, Suzana Makpol + Show 4 more

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https://doi.org/10.3390/molecules18022200

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Abstract

The present study was designed to determine the radioprotective effects of Malaysian Gelam honey on gene expression and enzyme activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) of human diploid fibroblasts (HDFs) subjected to gamma-irradiation. Six groups of HDFs were studied: untreated control, irradiated HDFs, Gelam honey-treated HDFs and HDF treated with Gelam honey pre-, during- and post-irradiation. HDFs were treated with 6 mg/mL of sterilized Gelam honey (w/v) for 24 h and exposed to 1 Gray (Gy) of gamma rays at the dose rate of 0.25 Gy/min. Gamma-irradiation was shown to down-regulate SOD1, SOD2, CAT and GPx1 gene expressions (p < 0.05). Conversely, HDFs treated with Gelam honey alone showed up-regulation of all genes studied. Similarly, SOD, CAT and GPx enzyme activities in HDFs decreased with gamma-irradiation and increased when cells were treated with Gelam honey (p < 0.05). Furthermore, of the three different stages of study treatment, pre-treatment with Gelam honey caused up-regulation of SOD1, SOD2 and CAT genes expression and increased the activity of SOD and CAT. As a conclusion, Gelam honey modulates the expression of antioxidant enzymes at gene and protein levels in irradiated HDFs indicating its potential as a radioprotectant agent.

Highlights

Ionizing irradiation is known to induce oxidative stress due to overproduction of reactive oxygen species (ROS) causing disturbances to cellular metabolism
The relative expression value (REV) of SOD1 gene was significantly decreased in human diploid fibroblasts (HDFs) exposed to
SOD2 gene was up-regulated in honey-treated HDFs and irradiated HDFs with pre-treatment of Gelam honey as compared to irradiated HDFs without honey treatment

Summary

Introduction

Ionizing irradiation is known to induce oxidative stress due to overproduction of reactive oxygen species (ROS) causing disturbances to cellular metabolism. Earth or from cosmic rays or is synthetically produced at radiation facilities such as nuclear reactor plants, by X-rays, CT scans and radiotherapy [1,2]. It is estimated that 80% of radiation exposure was received from natural sources [3]. The exposure from artificial sources was low as compared to exposure from natural sources, the increase in radiation applications has resulted in increased numbers of humans exposed to radiation. The level of radiation exposure for radiation workers is monitored, they are more frequently exposed to radiation as compared to the public and may have higher risk to face radiation accidents. For patients who undergo radiotherapy treatment, the radiation does kill the cancer cells and produced side effects whereby the irradiated cancer cells will directly transmit damaging signals to normal non-irradiated cells and produce similar effects as in the irradiated cancer cells [5]

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