| المستخلص: |
Herbicides are widely used for farming purposes such as increasing crops and reducing undesirable weeds. Although, health and safety guidelines have been created already, herbicides can be misused by farmers, which can lead to health risks if they are exposed to herbicides through the skin or via inhalation. Glyphosate (G) is an active ingredient in the most common formulation, Roundup® (R), which is the largest selling herbicide around the world. R contains Polyethoxylated tallowamine (POEA) as the major surfactant, and it has the highest toxicity in prior testing either by itself or in combination with G in the formulation R. The aim of this study was to investigate the cytotoxicity and genotoxicity of G and R on skin and lung cells. The cytotoxic effect was investigated using human skin keratinocyte (HaCaT), which were previously derived from a 62 year old man, and human Fetal Lung Fibroblast (MRC-5) cell lines, which previously derived from a 14 week old male fetus aborted from a 27 year old woman. Cells were exposed to G and R for 1, 4 and 24 hours and the cytotoxicity observed based on the mitochondrial activity and nuclei staining. This was achieved by use of the MTT and Crystal Violet assays. The genotoxic impact was investigated using human skin keratinocyte (HaCaT) only. HaCaT cells were exposed to G and R for 24 hours for detecting DNA damage, apoptosis and necrosis using The cytokinesis-block micronucleus cytome assay (CBMN assay). In the present findings, R was more toxic than its active ingredient G. The MTT and Crystal Violet assays results showed that HaCaT cells exposed to R induced cell killing at the dose of 0.05 and 0.005 M after 1, 4 and 24 hours treatment while G caused only weak effects at the same concentrations. All times of exposure except 24 hours, resulted in significantly decreased (P < 0.002) the cell survival, when assessed using the MTT assay and significantly decreased (P < 0.005) cell number when assessed by the Crystal Violet assay. MRC-5 had almost the same results in toxicity effects as HaCaT cells for the 1 and 24 hours treatment with G and R assessed by the MTT assay. Both R and G induced DNA damage on HaCaT cells. The frequency of micronuclei (MNi) in R was more than G exposure at 24 hrs. In 24 hours exposure of G and R, apoptosis and necrosis were shown for both R and G and elevated in R at 1x10-4 M to nearly 5% and with 0.5x10-4 M to 13% necrosis. Nuclear bud and bridge were only observed following treatment by R at 1x10-4 M after 24 hours exposure. In conclusion, Roundup has the potential to cause cytotoxicity and genotoxicity in HaCaT and MRC-5 cells more than glyphosate. Hence, Roundup likely poses more hazard if exposed via skin or inhaled in occupational settings.
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