{"id":37933,"date":"2025-03-13T00:01:39","date_gmt":"2025-03-13T04:01:39","guid":{"rendered":"https:\/\/beyondpesticides.org\/dailynewsblog\/?p=37933"},"modified":"2025-03-12T17:46:25","modified_gmt":"2025-03-12T21:46:25","slug":"study-of-pesticide-mixtures-and-intestinal-barrier-dysfunction-further-highlights-regulatory-deficiencies","status":"publish","type":"post","link":"https:\/\/beyondpesticides.org\/dailynewsblog\/2025\/03\/study-of-pesticide-mixtures-and-intestinal-barrier-dysfunction-further-highlights-regulatory-deficiencies\/","title":{"rendered":"Study of Pesticide Mixtures and Intestinal Barrier Dysfunction Further Highlights Regulatory Deficiencies"},"content":{"rendered":"

(<\/span>Beyond Pesticides<\/span><\/i>, March 13, 2025) Study results published in <\/span>Pesticide Biochemistry and Physiology<\/span><\/i><\/a> \u201csuggest that combined [pesticide] exposure may further amplify the toxicity and compromise the intestinal barrier.\u201d The researchers studied the toxic effects of the insecticides <\/span>abamectin<\/span><\/a> and <\/span>spirodiclofen<\/span><\/a>, as well as the fungicide <\/span>fluazinam<\/span><\/a>, individually and in combination. In exposing mice and Caco-2 cells to these pesticides,\u00a0<\/span>t<\/span>he results show\u00a0the disruption of intestinal functions and highlight the need to assess potential <\/span>synergistic effects<\/span><\/a> of <\/span>pesticide mixtures<\/span><\/a> as a part of the regulatory review process.<\/span>\u00a0<\/span><\/p>\n

Effects on the intestinal barriers of mice represent a threat to \u201cthe first line of defense against the external environment,\u201d the researchers say. The intestinal mucosal epithelial structure plays an important role in preventing harmful substances from entering the intestines and causing damage to cells.<\/span>\u00a0<\/span><\/p>\n

[<\/span>Caco-2 cells<\/span><\/a> represent a human cell line, derived from a colon cancer patient\u2019s tissue, and mimic the small intestine. These cells are vital in research as a model of the intestinal epithelial barrier.]<\/span>\u00a0<\/span><\/p>\n

\u201cCurrently, most studies investigating the effects of pesticide residues on the barrier function of Caco-2 cells concentrate on the exposure to a single residue, while the potential toxic effects arising from the concurrent presence of multiple pesticide residues remain largely overlooked,\u201d the authors say. As Beyond Pesticides has <\/span>previously reported<\/span><\/a>, scientists and advocates have urged prioritizing further studies on the effect of mixtures on organisms for many decades, given that exposure in the environment is not limited to a single pesticide at a time.\u00a0<\/span>\u00a0<\/span><\/p>\n

“[R]ecent <\/span>studies<\/span><\/a> have increasingly highlighted the toxic effects of abamectin on non-target organisms and human cells,\u201d the researchers state. The combination of pesticides has been widely used due to widespread resistance among red spider mites to individual pesticides. The researchers continue: \u201cCurrently, research predominantly focuses on individual exposure to pesticides, while the interaction effects of three commonly used pesticides remain largely unexplored. Therefore, it is essential to investigate the potential interaction effects of abamectin, fluazinam, and spirodiclofen pesticides with high detection rates in actual samples on the impairment of intestinal barrier function and transepithelial transport.\u201d<\/span>\u00a0<\/span><\/p>\n

The study subjected both mice and Caco-2 cells to concentrations of the three pesticides, representing acceptable daily intake (ADI) values as well as environmental exposure concentrations. After 28 days, histopathological changes in the colon of the mice were evaluated. For the Caco-2 cell cultures, viability assays and an analysis of gene expression were performed.\u00a0<\/span>\u00a0<\/span><\/p>\n

Findings from the histopathological analysis (a microscopic examination of tissues) \u201csuggest that exposure to both individual and combined pesticides may induce structural damage to the mouse colon, with fluazinam and spirodiclofen exposure further exacerbating this damage,\u201d the authors report.\u00a0<\/span>\u00a0<\/span><\/p>\n

Between the mouse models and cell assays, treatment with the pesticide mixtures shows compromised intestinal integrity as well as changes in the transport and uptake of the chemicals. The study reports: \u201c[A]<\/span>nalysis of mouse intestines revealed synergistic damage in those exposed to a binary mixture of abamectin, fluazinam, and spirodiclofen… The studies on the transport in Caco-2 cells revealed that the combined exposure to abamectin and spirodiclofen resulted in transport amounts that were 5.37 and 19.98 times greater than those observed with individual exposures, respectively.\u201d <\/span>These results highlight how the uptake of chemicals into cells can differ not only between single pesticides but also when exposure occurs in combination.\u00a0<\/span>\u00a0<\/span><\/p>\n

The effects of pesticide mixtures seen in this study highlight the importance of considering <\/span>synergy<\/span><\/a> in risk assessments. \u201cThese findings enhance our understanding of the interactions among multiple pesticide residues and further clarify the complexity of these interactions and their impact on human exposure,\u201d the authors conclude. (See additional coverage on health effects from pesticide mixtures <\/span>here<\/span><\/a> and <\/span>here<\/span><\/a>.)\u00a0<\/span>\u00a0<\/span><\/p>\n

Additional research referenced in the study supports the findings of intestinal damage from pesticide exposure. This includes:<\/span>\u00a0<\/span><\/p>\n