Hepatic, renal, and pancreatic damage associated with chronic exposure to oral and inhaled 2,4-dichlorophenoxy acetic acid (2,4-d): an environmental exposure model in rats

2,4-D Herbicide-Induced Hepatotoxicity: Unveiling Disrupted Liver Functions and Associated Biomarkers

2,4-dichlorophenoxyacetic acid (2,4-D) is a widely used herbicide worldwide and is frequently found in water samples. This knowledge has prompted studies on its effects on non-target organisms, revealing significant alterations to liver structure and function. In this review, we evaluated the literature on the hepatotoxicity of 2,4-D, focusing on morphological damages, toxicity biomarkers and affected liver functions. Searches were conducted on PubMed, Web of Science and Scopus and 83 articles were selected after curation. Among these studies, 72% used in vivo models and 30% used in vitro models. Additionally, 48% used the active ingredient, and 35% used commercial formulations in exposure experiments. The most affected biomarkers were related to a decrease in antioxidant capacity through alterations in the activities of catalase, superoxide dismutase and the levels of malondialdehyde. Changes in energy metabolism, lipids, liver function, and xenobiotic metabolism were also identified. Furthermore, studies about the effects of 2,4-D in mixtures with other pesticides were found, as well as hepatoprotection trials. The reviewed data indicate the essential role of reduction in antioxidant capacity and oxidative stress in 2,4-D-induced hepatotoxicity. However, the mechanism of action of the herbicide is still not fully understood and further research in this area is necessary.

Digestive tract toxicity associated with exposure to 2,4-dichlorophenoxyacetic acid in rats

2,4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide of the chlorophenoxy class and the second most widely used herbicide applied to several different crops worldwide. Environmental factors, especially those related to diet, strongly affect the risk of developing cancer of the gastrointestinal tract. There is currently no evidence to determine whether there is an association between 2,4-D exposure and gastrointestinal disorders. We evaluated the histological effect of chronic oral and inhalation exposure to 2,4-D on the digestive tract of rats. Eighty male adult albino Wistar rats were divided into 8 groups (n=10): two control groups, one for inhalation and one for oral exposure, and 6 groups exposed orally or by inhalation at three different concentrations of 2,4-D [3.71×10-3 grams of active ingredient per hectare (gai/ha), 6.19×10-3 gai/ha, and 9.28×10-3 gai/ha]. The animals were exposed for 6 months. The esophagus, stomach, and intestine were collected for histopathological analysis. Animals exposed to 2,4-D had hyperkeratosis of the esophagus, regardless of the exposure route. All animals exposed to a higher concentration of 2,4-D orally presented mild dysplasia of the large intestine. In the small intestine, most animals exposed to moderate and high concentrations of 2,4-D had mild dysplasia. No gastric changes were observed in any of the groups studied. Chronic exposure to 2,4-D, especially at moderate and high concentrations, regardless of the exposure route, caused reactive damage to the esophagus (hyperkeratosis) and dysplastic changes to the intestine.

The antioxidant study proprieties of Thymus munbyanus aqueous extract and its beneficial effect on 2, 4-Dichlorophenoxyacetic acid -induced hepatic oxidative stress in albino Wistar rats

Herein, we investigated the antioxidant and hepatoprotective effects of thyme (Thymus munbyanus: AETM) on 2,4-dichlorophenoxyacetic acid (2,4 -D) - induced liver oxidative damage in rats. The phytochemical study of AETM revealed potent antioxidant properties owed to its richness in phenolic compounds including flavonoids, tannins, and phenolic acids. Further, in vivo animal study was conducted on 24 Wistar rats divided equally into control group and three treated groups, receiving orally AETM (10 ml/kg body weight (b.w), 2,4-D (5 mg/kg (b.w) and AETM + 2,4 - D (combined treatment) for 30 consecutive days. The results showed a significant increase in the enzymatic activity of transaminases (AST, ALT), alkaline phosphatase (ALP), gamma-glutamyltransferase (γ-GT), lactate dehydrogenase (LDH), and the levels of malondialdehyde (MDA) and carbonyl proteins (CPO), along with a significant decrease in plasma total protein, albumin, hepatic glutathione (GSH) contents, and the enzymatic activity of the hepatic antioxidant markers (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione- S- transferase (GST)) in 2,4- D treatment compared with control. Moreover, no significant changes in these parameters were noticed in AETM treated animals as compared to control, and hence the combined treatment (AETM + 2,4- D) showed a marked enhancement in the above altered hepatic functional and antioxidant parameters and liver histopathology. In conclusion, AETM, owing to its richness with phenolic compounds proved to be an efficient antioxidant against 2,4-D - induced liver oxidative damage, and hence complementary studies would be needed to appear the use of these compounds as supplements in treating liver impairment.