الفهرس 
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Abstract
The present investigation explored the problem of human exposure to very low concentrations of pesticides during the critical stages (e.g., gestation and lactation), and the protective effect of an antioxidant substance (e.g., vitamin E), not only in adult females but also in the born offspring. For these purposes, three pesticides (e.g., atrazine, chlorpyrifos and endosulfan) and their tertiary mixture were used. The ameliorative effect of co-administration of vitamin E (α- tocopherol) in conjunction with the tested pesticides was also investigated. Each pesticide was mixed in the rodent diet at its respective “Acceptable Daily Intake, ADI” (e.g., 31.0, 44.0 and 30.0 mgkg-1 b.w/day, respectively, for atrazine, chlorpyrifos and endosulfan). Other quantities of feed were enriched with the three pesticides. Finally, the rodent feeds were formulated in nuggets and the practical added pesticides were analyzed by conventional methods. Vitamin E was administered orally to the mouse dams. The work included two separate experiments; namely gestation and lactation experiments. In gestation experiments, the mouse dams were treated during gestation period only (21 days) while in lactation experiments the mouse dams were treated during lactation period only (21 days). After the weaning (42 days), pups and dams were killed and selected organs and blood samples were collected for analyses. Either during gestation or lactation, the experimental mouse dams consisted of 10 groups: group1: diet free of pesticides (control group), group 2: diet free of pesticides+ oral vitamin E ( vit group), group3: diet enriched with ATZ (31.0 mg kg−1 bw), group 4: diet enriched with chlorpyrifos (44.0 mg kg−1 bw), group 5: diet enriched with endosulfan (30.0 mgkg-1 bw), group 6: diet enriched with the three pesticides ( mixture group), group 7: diet enriched with atrazine+ oral vitamin E (100 mg kg−1 per mouse); group 8: diet enriched with chlorpyrifos + oral vitamin E (100 mg kg−1 per mouse); group 9: diet enriched with endosulfan + oral vitamin E (100 mg kg−1 per mouse), and group 10: diet enriched with the pesticide mixture + oral vitamin E (100 mg kg−1 per mouse). Drinking water was allowed ad libitum up to 42 days.
Each of gestation and lactation experiments included 20 sub-groups designated for male and female pups. These pups were considered exposed indirectly to the above mentioned treatments applied to the mouse dams. The criteria of evaluation included: body and internal organs weights, liver and kidney biochemical determinations, and histopathological examinations.
Generally the tested pesticides caused alterations in organs weights (e.g., liver, kidney, heart, spleen, ovary and testes), biochemical parameters (e.g. AST, ALT, ALP, BuChE, Urea, MDA, SOD and CAT), and histopathological changes in the internal organs. These alterations were occurred in the all tested animals received the pesticidal treatments. Compared with the control results either in dams or their pups, the tested pesticides induced high elevation in AST, ALT, ALP, urea and MDA and high decline in BuChE, SOD and CAT activities. Biochemical alterations (e.g., MDA and BuChE) recorded for the mouse dams treated with the mixture, for example, during gestation were generally higher than those during lactation, while the opposite was obtained for SOD and CAT. The pups either from gestation or lactation treatments were more affected than the dams with respect to alterations in MDA and BuChE activities, while the opposite was achieved with respect to SOD activities. Alteration in catalase activity for dams was nearly equaled to that for pups. No obvious gender-related effects. The ameliorative effect of vitamin E, based on estimating the “Amelioration Index; AI” revealed the powerful effect of this vitamin in alleviating the oxidative stress exerted by the tested pesticides.
The estimated biochemical parameters were affected to different degrees based on the tested pesticide, the concerned biochemical parameter, the stage of animal treatment (e.g., gestation or lactation), as well as the stage and gender of the tested mouse (e.g., dams, female pups and male pups). Since mouse pups from dams exposed to pesticides during lactation were dependent only on breast feeding, the findings of the present investigation reveal that toxic effects of these pesticides, as well as ameliorative effect of vitamin E, occurred via lactation process. In pups from dams exposed to pesticides during gestation, the toxic effects, as well as ameliorative effect of vitamin E, occurred mainly via gestation and probably through the mother’s milk also. In light of the results of the present study, it may be difficult to conclude, in a general statement, which exposure stage was much affected following exposure to each of the tested pesticides. But we can suggest which stage was more vulnerable to alteration in a specific parameter (e.g., MDA, SOD, CAT, BuChE, etc.). Based on changes in the levels of the biochemical parameters following exposure to the tested pesticides, the obtained results could be elucidated. The effect of ATZ (in terms of percent of change) as example on MDA was more pronounced in exposure during lactation (16.4%), while the percent of change for SOD in gestation was nearly equaled to that in lactation stage (ca. 23.5%). On the other side changes in MDA level was higher in males (27.4%) than in females (21.3%) with respect to gestation treatment while the opposite was obtained for the pups in lactation treatments. Histologically, the tested pesticides induced impairment in tissues of the experimental dams and their offspring, both in those exposed during gestation and lactation. Taking into consideration that exposure of dams to the tested pesticides during gestation was followed with a withdrawal period (ca. 21days), this may lead us to consider that lactation stage was more affected than gestation stage.