Detrimental effects of 6 months exposure to very low doses of a mixture of six pesticides associated with chronic vitamin deficiency on rats.

This study aimed to evaluate the long-term low-dose effects of exposure to a mixture of 6 pesticide active substances (diquat, imazamox, imazethapyr, tepraloxydin, bentazone, acifluorfen) and to elucidate if chronic vitamin deficiency can influence their toxicity. Two hundred Wistar rats were divided in 4 groups: a vitamin-sufficiency control group, a vitamin-deficiency control group, a vitamin sufficiency test group and a vitamin-deficiency test group. The test groups were treated with the aforementioned pesticides at doses 100 times lower than the corresponding NOAEL. After 6 months, ten rats from each group were sacrificed and a complete evaluation of blood and urine biochemistry, biomarkers of oxidative stress, xenobiotic detoxification enzymes and lysosomal enzymes and organ histopathology was performed. The pesticides mixture and vitamin deficiency determined an increase in alkaline phosphatase levels and urinary calcium levels, abnormal serum lipid profile, and a decrease of total blood proteins levels, red blood cells, haematocrit and haemoglobin. The combination of the two stressors up-regulated CYP1A1, CYP1A2, CYP2B1 and GST levels. This study provides a new proof for the need to move forward from single chemical testing to a more complex approach to account for the multitude of stressors that can challenge the setting of real safety levels.

The Use of the Adaptation Potential Reduction Model for Reproductive Toxicity Research In Vivo.

The modeling of adaptation potential decrease in rats due to modification of the diet's vitamin-mineral composition allows to increase animals' sensitivity to toxic load in reprotoxicological experiments. The threshold values of vitamins B1, B2, B3, and B6 and mineral substances Fe3+ and Mg2+ in the diet, which lead to a considerable reduction of laboratory animals' adaptation potential, have been determined as 19% (from the basic level in the diet) for males and 18% for females. The efficiency of this model has been confirmed in a reprotoxicological experiment with glyphosate as a toxic factor: the action of the toxic factor against the background of reduced availability of B vitamins and salts Fe3+ and Mg2+ led to significant changes in such indicators of reproductive function as mating efficiency, postimplantation loss, and the total number of alive pups, while the toxic effect of glyphosate was not so pronounced against the normal level of essential substances. The obtained results prove that this adaptation potential reduction model can be recommended for the research of the low-toxicity objects reproductive toxicity in rats and for the safety assessment of novel food, in particular.

The effect of chronic vitamin deficiency and long term very low dose exposure to 6 pesticides mixture on neurological outcomes - A real-life risk simulation approach.

We investigate the long-term effect of very-low dose exposure to a mixture of six pesticides associated with hydrophilic vitamin deficiency on the neurobehavioral outcomes of rats. Two hundred Wistar rats were divided into four groups, two control groups, a vitamin sufficient control group and a vitamin deficiency control group and 2 test groups, a vitamin sufficient test group, and a vitamin deficiency group. The test groups were exposed for 9 months to a mixture of diquat, imazamox, imazethapyr, tepraloxydin, bentazone and acifluorfen in doses of 0.01xNOAEL (mg/kg bw/day). After 9 months of exposure, the behavior changes were evaluated by open field test and elevated plus maze test and the memory was assessed by passive avoidance test. Chronic vitamin deficiency decreased locomotor and special orientation activity and increased anxiety-like behavior in rats. Exposure to very low doses of a mixture of 6 pesticides caused central nervous effects, manifested as decreased locomotor activity, and increased anxiety levels. Vitamin deficiency and low dose chronic pesticides mixture exposure thus affected the central nervous system, especially long-term memory.

Model of vitamin and mineral deficiency for toxicological research: Apoptosis activity under conditions of CCL4 intoxication.

The apoptosis activity and clinical state in vitamin and mineral supplemented male Wistar rats was evaluated after carbon tetrachloride exposure (CCL4). The animals were divided equally into 6 groups (3 control groups and 3 exposure groups) with the control groups (C-75, C-30, C-19) receiving AIN-93, a specific diet for rodents, consisting of a 75%, 30% and 19% ratio of vitamins (B1, B2, B3, B6) and minerals (Fe3+ and Mg2+) and exposure groups (E-75, E-30, E-19) receiving the same diet paradigm as with the control groups but with the additional CCL4 administered once a week as an olive oil solution (control groups received the same ratio of olive oil without CCL4) for a duration of 64 days. The systemic condition of the male Wistar rats was evaluated based on morphological parameters and hematological and biochemical analysis, whereas the apoptosis activity in the liver was evaluated via comet assay techniques. The apoptosis activity in the liver of control and exposure groups increased compared to the decrease in the essential substance provisions with the E-75 group reaching 129% (p < 0.05) higher levels compared to the C-75 group, and 98% (p < 0.05) and 23% (p > 0.05) higher in the E-30 and E-19 groups compared to the C-30 and C-19 groups, respectively. From the apoptosis results and clinical state evaluation, it is clearly demonstrated that the effectiveness of using apoptosis activity as a biomarker after CCL4 exposure and the vitamin and mineral absorption capability in male Wistar rats can be applied as an evaluating method for toxicological research.