The effects of glyphosate-resistant genetically modified soybean on protein metabolism and on rats’ antioxidant system.

Study: http://www.inenbiol.com/images/stories/dusert/2021/Chorna/Chorna_dis.pdf

Author(s): Chorna I.V.

Article Type: Study

Abstract:

One of the transgenic crops widely used both in agriculture and in the food industry is genetically modified soybean (GTS 40-3-2 line) with the new Roundup Ready trait. This transgenic soybean is resistant to Roundup herbicide due to the introduced gene of the Agrobacterium tumefaciens bacterium. The GM-soybean synthesizes bacterial 5-enolpyruvylshikimat-3-phosphate synthase (EPSPS) replacing the herbicide-inhibited enzyme in the plant, hence, after Roundup herbicide application in the field, the transgenic soybean continues to grow, whereas weeds die. The widespread use of Roundup Ready transgenic soybean and Roundup herbicide gives rise to concern about their safety for the environment, animal and human health. The thesis is devoted to the study of the long-term effects of glyphosate-resistant genetically modified soybean untreated and treated with Roundup herbicide and of the herbicide itself on female rat reproduction for two generations, on rat postnatal development and massometric parameters, on protein metabolism indicators (alanine transaminase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), creatinine, urea, uric acid and total protein) in tissues, urine and blood of three generations of rats. The content of carbonyl derivatives in tissues of three generations of rats and the state of their antioxidant protection system (concentrations of superoxide dismutase, catalase, glutathione and glutathione-dependent enzymes activity) were studied as one of the criteria for safety assessment of genetically modified organisms. The comprehensive study of the common effect of Roundup herbicide (the main active substance is glyphosate) and genetically modified soybean GTS 40-3-2 on histochemical and biochemical parameters of tissues, blood and urine of three generations of rats has been carried out for the first time; the impacts of both factors separately have been also investigated. The thesis has confirmed the negative effects of Roundup herbicide and transgenic soybean GTS 40-3-2 treated with herbicide on both structure and function of rat kidneys and livers, namely, causing reversible cellular swelling in kidney and liver cells, which is the most pronounced in the third generations of rats. The results of the dissertation research show the ability of soybean seeds to accumulate the herbicide “Roundup”, which can be partially neutralized due to heat treatment. It was found that long-term feeding of GM soy treated with the herbicide and the use of the herbicide “Roundup” together with drinking water leads to increased mortality of rats of the next two generations, especially in the first two months of life. In addition, the changes in their massometric parameters (an increase in liver mass among the experimental groups), especially in the F1 and the F2 generations of rats were established.

Analysis of biochemical data of rat blood and liver obtained during carrying out the thesis work confirms the hepatocytes structure disruption, namely, some damage to their cell membranes, as evidenced by an increase in the aminotransferase level in the blood (especially ALT). An іncrease in alanine aminotransferase activity and decrease in coefficient De Ritis Ratio (AST/ALT ratio) indicates the liver origin of this enzyme. Some changes in other biochemical parameters, in particular, an increase in the level of average molecules in blood (as indicator of intoxication) prove the toxicity of this herbicide. Studies have shown that in two experimental groups (groups IV and V) the level of oxidative modification of proteins increases, as evidenced by a decrease in the content of SH groups and an increase in carbonyl derivatives, which subsequently become sensitive to proteolysis. The obtained results testify to the increase in the number of reactive oxygen species, contributing to the initiation of free radical processes in the liver and kidney cells of the rats received the herbicide with drinking water and the rats fed with soybean seeds, containing the herbicide residues. The depletion of antioxidant protection system and the oxidant-antioxidant system imbalance have been also observed. The glutathione peroxidase and glutathione transferase activities also decreased in blood, livers, and kidneys of the rats received the Roundup herbicide with drinking water and of the rats fed with transgenic soybean treated with herbicide. The decrease was more pronounced for the F1 and F2 generations of rats. For the rats fed with untreated transgenic soybean the antioxidant protection enzymes activity remains almost unchanged compared to the control group.

Keywords: genetically modified organisms, transgenic organisms, glyphosate-resistant, hepatocytes, Roundup herbicide, detoxification, rat, rats, rodent, rodents, GMO, soy, soybeans, soybean

Citation:

Chorna I.V. (2021). The effects of glyphosate-resistant genetically modified
soybean on protein metabolism and on rats’ antioxidant system.

Category:

• Health effects