SUBCHRONIC MANCOZEB TREATEMENT INDUCED LIVER TOXICITY VIA OXIDATIVE STRESS IN MALE WISTAR RATS

Mancozeb is a manganese/zinc ethylene-bis-dithiocarbamate fungicide that is widely used in agriculture to control a broad variety of fungal infections of both vegetables and ornamental plants. The present study has been carried out to investigate the possible effect of mancozeb on animal the oxidative stress and some of the biochemical markers in male Wistar rats. In this experiment, adult male rats weighing between 200 and 250 g were treated per os for 4 weeks with two different doses of 800 and 1200 mg/kg per day. Reduced glutathione (GSH) levels were decreased in all treated groups compared to control ones. It has been observed a significant increase in the fresh weight of liver in individuals of both doses. Moreover, mancozeb exposure caused a significant (p < 0.05) fall in aspartic aminotransferase (AST) and alanine aminotransferase (ALT) in group treated with 1200 and 800 mg/kg/day. Similarly, alkaline phosphatase (ALP) activity underwent a significant (p < 0.05) increase in both groups. The obtained observations clearly reveal hepatotoxic effects of mancozeb in rats and constitute, therefore, an environmental health risks to living organisms.

Comparative histopathological effects of ethylene-bis-dithiocarbamate on the testis in rabbits and rats

Maneb is an ethylene-bis-dithiocarbamate fungicide used in the control of the fungal diseases of plants. Males of domestic rabbits Oryctolagus cuniculus and Wistar rats received daily by gavage 2 and 3 mg/kg body weight of Maneb for 3 weeks. At the end of the treatment, the animals were sacrificed and the testis's samples were weighed and placed in formol 10% solution. The histopathology changes study was made in accordance with Martoja and Martoja, 1967 method. The obtained results show a very considerable reduction of the weight of testes in treated animals compared to the control group especially in the rabbits. A very reduction in testosterone concentration was noticed in the treated rabbits. The histological observation showed that no effect was observed in the testes in rats. Then, the testicle of treated rabbits with 2 mg/kg body weight reveal seminal tubules in involution Sertolienne and Leydig cells are a little too visible. White rabbits treated 3 mg/kg indicates that there is no spermatozoa in the epididymis, the most of the tubules are empty as compared to control. The testis in the control show normal spermatogenesis and the mitoses are distributed to all levels and spermatozoa are observed in many tubules and epididymis. In conclusion, administration Maneb with the used doses affects histological deformation in the testis of rabbits.

Hypothyroidism after medium exposure to the fungicide maneb in the rabbit Cuniculus lepus

Dithiocarbamate are widely used as fungicides because of their efficacy against a broad spectrum of fungi and their associated plant diseases. Maneb is one of Ethylenebisdithiocarabamate (EBDCs). Males domestic rabbits received (by gavage) 2, 3, 5 and 8 mg/kg body weight of maneb, for a period of 5 weeks. Total body weights were measured at 48 h interals. At the end of the experimental period, animals were sacrified and some of organs such as, liver, testes, spleen and the kidney were weighted. The obtained data reveal that the used fungicide induces a remarkable increase in body weight of all the treated animals, particularly with the higher dose as compared with control group. An increase in plasma triglycerides, glucose and of cholesterol levels has been recorded. Moreover, a reduction in the weight of kidneys and testes in animals receiving 5 and 8 mg/kg, while a remarkable increase in the weight of the liver has been observed. Thyroxin concentrations underwent a significant reduction in treated individuals. A very significant reduction in, the number, speed and mobility of spermatozoa accompanied with a high ratio of spermatozoa deformation in the treated groups was noticed. In conclusion, administration of maneb causes thyroid pathology and affects the biology of sperms with histological deformation of testes.

The toxicological effects of the herbicide 2,4-DCPA on progesterone levels and mortality in Wistar female rats

The effect of the ester butylglucol of 2,4-Dichlorophenoxyacetic acid (herbicide) on the rate of fertilization and on progesterone levels during gestation in rats, has been studied. The experiments consisted of four groups; one receiving the drug in the drinking water at a concentration of 125 mg/kg/day (the agriculture dose), the second and the third group received per os doses of 50 and 100 mg/kg/day of the herbicide, while the fourth group served as controls. The obtained results show that all treatments lead to a decrease in both indexes of females' fertility and in that of newborn mortality. On the other hand, the index of fertilization has been highly affected by the drug application, with a clear delay in fertilization in animals treated with 100 mg/kg/day and 125 mg/kg/day. Progesterone levels have also been suppressed in individuals receiving the herbicide at 50 and 125 mg/kg/day.

Urinary markers of workers chronically exposed to mercury vapor

The effects of chronic mercury intoxication on urinary markers in workers from northeast Algeria were investigated. Workmen were chosen from highly and moderately mercury-exposed factories, while controls were selected from a nonexposed site. The number of proteinuria cases were higher in the highly exposed subjects, although the nature (glomerular or tubular) of proteinuria remains unclear. However, it appears difficult to assess the degree of renal disturbance among the different exposure levels, such as the amount of excreted proteins, which have not clearly reflected the kidney lesion severity. The results also reveal that urine acidity increased progressively with increased levels of exposure, while a remarkable inverse relationship between urinary pH and urinary Hg in the highly exposed workers has been recorded. Furthermore, the significant differences in blood and urinary mercury concentrations of the three sites reflect the dose-response relationships.

The effect of duration of exposure to short days on the gonadal response to long days in male starlings (Sturnus vulgaris)

Photorefractory male starlings (Sturnus vulgaris) were transferred from a photoperiodic schedule of 18 h light:6 h dark to 8 h light:16 h dark for 2, 4, 6 or 10 weeks, and then photostimulated by exposure to 18 h light:6 h dark. Testicular dimensions were measured at regular intervals by laparotomy. There was no change in testicular volume in birds photostimulated after 2 weeks under a photoperiod of 8 h light:16 h dark, but a cycle of testicular growth followed by regression occurred in the other groups. Testicular volume was increased significantly by 20 days under 18 h light:6 h dark in all three groups; regression began after 45, 65 and 75 days in birds pre-exposed to 8 h light:16 h dark for 4, 6 and 10 weeks, respectively. These results are discussed in relation to other evidence for the progressive development of photosensitivity.

Acquisition of photosensitivity in castrated male starlings (Sturnus vulgaris) under short day photoperiods

Photorefractory castrated male starlings were transferred from a photoperiodic schedule of 18 h light:6 h dark to 1 h light:23 h dark, 5 h light:19 h dark, 8 h light: 16 h dark or 11 h light:13 h dark. Plasma concentrations of LH were measured in blood samples taken at regular intervals, to give an indication of the reacquisition of photosensitivity under these schedules. Concentration of plasma LH increased after 35, 38, 35 and 63 days, respectively; there was a steady increase in LH in all groups, but the increase under 11 h light:13 h dark was much slower than in the other groups. In contrast, birds held under 18 h light:6 h dark showed no increase in LH. Thus, starlings became photosensitive at a similar rate under fixed photoperiods of 8 h light:16 h dark or shorter, but took longer to acquire photosensitivity under 11 h light:13 h dark.

Thyroxine treatment induces changes in hypothalamic gonadotrophin-releasing hormone characteristic of photorefractoriness in starlings (Sturnus vulgaris)

Photosensitive intact male starlings were transferred from short days (8L:16D) to 11L:13D for 16 weeks, and were therefore sexually mature. Experimental groups were (i) held under 11L:13D and given exogenous thyroxine dissolved in the drinking water for 6 weeks or (ii) given thyroxine for 6 weeks and then transferred from 11L:13D to long days (18L:6D) for a further 6 weeks, while control groups were transferred to long days (18L:6D) either (iii) for 6 or (iv) for 12 weeks, or were (v) maintained under 11L:13D throughout. Changes in testicular size and plumage molt were monitored at regular intervals during the 12-week period. At the end of the experiment, the birds were killed and hypothalamic gonadotropin-releasing hormone (Gn-RH) content and testicular mass were measured. Treatment with exogenous thyroxine caused rapid testicular regression followed by plumage molt, and after 6 weeks hypothalamic Gn-RH content was much reduced, to an even greater extent than that in control birds exposed to long days for 6 weeks. After 6 weeks of thyroxine treatment, withdrawal of exogenous thyroxine and exposure to long days for a further 6 weeks caused no increase in testicular size, and caused a further reduction in hypothalamic Gn-RH content to a level similar to that in controls after 12 weeks of exposure to long days. The results confirm previous findings that thyroxine induces a state of photorefractoriness in sexually mature starlings and show for the first time that the treatment mimics the effect of long days in reducing Gn-RH content in the hypothalamus.