الفهرس 
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Abstract
Lead is an environmental pollutant and metabolic poison with a wide variety of toxic effects and adverse influence on reproduction (Thomas and Brogan, 1993). The present study aimed to investigate the toxic effect of lead acetate on male rat reproduction and protective effect of vitamin E and pumpkin seeds oil through studying the effect of lead acetate on body weight, male reproductive organ weight, hematological parameters, lead residue in testes, antioxidant enzymes, testosterone hormone, sperm gram, expression of Nrf2 (nuclear related factor) and histopathological changes of testes. Sixty male albino rats were used in this study. These rats were divided into 4 groups each one contains 15 rats as the following:
Group I: kept as control and given olive oil by stomach tube for 65 day.
Group II: was given 1.5gm/L lead acetate daily in drinking water for 65 day.
Group III: was given 1.5gm/L lead acetate plus 600mg/kg.bwt vitamin E dissolved in olive oil 3 times/week by stomach tube for 65 day.
Group IV: was given 1.5gm/L lead acetate plus 288mg/kg.bwt pumpkin seeds oil dissolved in olive oil 3times/week by stomach tube for 65 day.
The experiment were continued to 65 day, during the experiment all groups observed daily, weighed weekly. Mean body weight was calculated by weighting rats every 2 week. Collection of blood samples were performed at the end of the experiment. Blood samples were divided into: blood for hematological studies collected in clean blood collecting tubes with EDTA as an anticoagulant and serum stored at -20Co for detection of testosterone hormone. Tissue specimens from testes were taken at the end of the experiment and preserved at -80Co for antioxidant enzymes, lead residue, molecular study and histopathological changes on testes. For sperm gram (sperm viability and sperm abnormality) head of epididymis were taken and putted in normal physiological saline. Hematological examination include erythrocytic count, hemoglobin concentration, packed cell volume (PCV %), MCH, MCHC, total leukocytic count and differential leukocytic count, while serum for testosterone hormone. Tissue specimens from testes were taken for antioxidant enzymes include GSH, GST and MDA, lead residue in testes, molecular study of mRNA expression of Nrf2 by Real time PCR. Specimen from epididymis taken immediately after scarification and put in normal physiological saline for sperm gram and specimens from testes were collected immediately after scarification and kept Bowen’s reagent for histopathological examination.
The results obtained in this study could be summarized as the following:
There is no statistical difference of mean body weight at first and second weeks of experiment, while from 4th week to 8th week there were significant decrease of mean body weight in group П (rats administrated lead acetate), but in groups III (administrated lead acetate plus vitamin E) and in groups IV (administrated lead acetate plus pumpkin seeds oil) there was non significant decrease in body weight of rats compared to control group. The initial body weight of rats in different groups was nearly similar. There were statistical difference in the final body weight of rats in treated group of experiment .The weight gain of group II showed significant decrease compared with control group, while the weight gain in group III and group IV showed non significant decrease compared to control group. Regarding organ weight (gm) in different groups of experiment, there was no significant change in right testis, left testis and right cauda epididymal weight in all groups compared to control group, while significant decrease in left cauda epididymal weight in all experimental groups compared to control group. There was significant decrease in RBCs, Hb, PCV, MCH and MCHC in group II compared with control group, while there was no significant difference in group III and group IV compared with control group. Total leukocyte count level was high significant increase in group II compared with control group, while in group III and group IV was significant increase in compared to control. Lymphocyte, monocyte and granulocyte were high significant increase in group treated with lead acetate compared with control group, while significant increase in group III and group IV were detected compared with control group. The antioxidant study revealed a significant decrease in level of GSH and GST in group II, while non significant decrease in group III and group IV was detected comparing to control group. There was high significant increase in level of MDA in group II, while non significant increase in group III and group IV was detected comparing to control group. Lead residue in testes showed a significant increase in group II compared to control group, while non significant increase in group III and group IV was detected in comparison to control group. There was significant decrease in serum testosterone level in group II compared to control group, while non significant decrease in group III and group IV was detected compared with control group. There was significant decrease in live sperm% in group II, while non significant decrease in group III respectively compared to control group. The rats of group IV showed non significant increase in live sperm compared to group II and less significant decrease in live sperm compared to control group and group III. There was significant increase in dead sperm % in group II compared to control group, while non significant decrease in group III compared to control group. Group IV showed non significant decrease in dead sperm compared to group II and non significant increase in dead sperm compared to group I and group III. There was significant decrease in percentage of normal sperm in group II compared to control group, non significant difference in group III and group IV compared to control group. There was significant increase in head sperm abnormality(%) in group II treated with lead acetate compared to control group as small opened hock, abnormal sperm with broken neck and abnormal opened hock, while non significant difference in group III and group IV compared to control group. There was significant increase in tail sperm abnormality in group II compared to control group as bent tail and bent tail in eight manner, while non significant difference group III and group IV compared to control group. The relative quantities of Nrf2 relative to GAPDH mRNA were determined compared to the normal control group, the expression of Nrf2 was up-regulation in group II, while non significant difference in group III and group IV compared with control group. The histopathological examination of testes showed focal degeneration with lose of spermatogenic series that were noticed in some of the seminiferous tubules in group II compared with control group, while group III and group IV showed no histopathological alteration and the normal histological structure of the mature active seminiferous tubules with complete spermatogenic series compared with control group.