Abdelfettah El Feki

Exploration des effets cytotoxiques du plomb sur la fonction sexuelle endocrine et exocrine chez le rat pubère mâle et femelle. Mise en évidence d'une action apoptotique

This study deals with the impact of chronic exposure to lead on male and female fertility in rats. Male and female rats (3 months old) were fed on commercial tablets (SICO, Sfax). For drinking, some rats were given distilled water (T = controls), the other ones were given distilled water enriched with lead acetate, either 3 (P1 group) or 6 mg ml-1 (P2 group), for 15, 30, 45, 60 or 90 days. In male rats, absolute and relative weights of testis, epididymis, prostate and seminal vesicles were found to significantly decrease at day 15 in the P2 group and at day 45 in the P1 group. However, at day 60, these absolute and relative weights returned to control values. Lead-induced pathological changes in spermatogenesis were observed at day 15 by histological study: arrest of cell germ maturation, changes in the Sertoli cells, and presence of apoptotic cells revealed by borated toluidine blue in the testis. Presence of lead deposits was observed after histochemical staining using sodium rhodizonate. Serum testosterone level was found to be lowered at day 15 in both (P1) and (P2) groups, to display a peak at day 60, then to return to controls values, in spite of the continuation of the treatment. In female rats, absolute and relative weights of ovary and uterus were found unchanged. The vaginal smears practiced in females revealed the oestrus phase in all groups. Exposed females were mated with control males, and fecundity was assessed 15 days later by counting the number of pregnancies and the number of concepti per pregnancy. Fertility was found to be reduced in females of P1 and P2 groups as compared to control females (T group). Lead level in blood was found to be poorly correlated with the level of poisoning, whereas lead accumulation in tail was found to be dose-dependent. Therefore, lead accumulation in tail appears as a more reliable biomarker of exposure to lead. In summary, our study shows that chronic exposure to lead causes a double sexual disorder in rats: first, disorder deals with the hormonal function, which is affected at the early stages of poisoning, but is rapidly corrected; second, disorder deals with the genital tract, affecting the testis and the ovary, resulting in a reduced fertility in both P1 and P2 females, in spite of the presence of a normal oestrus. The cytotoxic effect of lead in males seems to be related to an apoptotic process.

Total and differential bulk cow milk somatic cell counts and their relation with antioxidant factors

In the present study, the relationship between total bulk milk somatic cell counts (BMSCC), differential BMSCC (macrophage, lymphocyte, and polymorphonuclear leukocytes), and antioxidant enzymes was investigated. Forty-three samples of bulk milk were selected randomly from eight dairy farms in the region of Sfax (Tunisia) in winter, from November 2005 to February 2006. Bulk milk samples were analyzed for antioxidant enzymes such as catalase, SOD and GSHPx activity and differential SCC. After that, milks were allotted according to their total SCC to: group 1, bulk milk with SCC below 1000x10(3) ml(-1); group 2, bulk milk with SCC from 1000x10(3) to 1500x10(3) ml(-1); group 3, bulk milk with SCC above 1500x10(3) ml(-1). BMSCC levels ranged from 400x10(3) to nearly 4000x10(3) ml(-1). Lymphocytes were the predominant cell type in all groups, but their proportion declined with the total BMSCC. Catalase and GSHPx activities were found to be significantly (P<0.001) correlated with total BMSCC and with the PMN population. In contrast, a weak correlation between the activity of the SOD and total or differential bulk milk somatic cells was observed. It has been suggested that milk cells, especially PMN, could generate a situation of oxidative stress in the mammary gland. Specifically, hydrogen peroxide and hydroxyl radicals were probably the most important reactive oxygen metabolites released by PMN.

Impact du thé vert “Camellia sinensis” sur les effets du vanadium sur la croissance et l’appareil génital du ratWistar mâle

ResumeCertains métaux lourds sont susceptibles de générer un stress oxydant et d’altérer les fonctions sexuelles et reproductrices mâles. L’apport d’antioxydants dans la nourriture semble être un moyen de limiter les effets cytotoxiques du stress oxydant.Dans ce cadre nous nous sommes proposés d’explorer l’impact de la consommation du thé vert «Camellia sinensis» riche en antioxydants (poly phénols …) sur les effets du vanadium sur la croissance corporelle et l’appareil génital du rat mâle.Pour cela, nous avons soumis pendant 90 jours des rats mâles de soucheWistar à un traitement par le méta vanadate d’ammonium (0,46g/l) en présence ou en absence de thé vert.Chez les rats exposés au toxique seul, l⇃sorption chronique, par voie orale, de vanadium a induit un ralentissement de la croissance corporelle et des organes génitaux (testicule, épididyme, prostate et vésicules séminales). Parallèlement, une diminution de la motilité et du nombres des spermatozoïdes a été observée. L’étude histologique des testicules a montré que les tubes séminifères étaient atrophiés, les différents stades de la spermatogenèse étaient perturbés, ce qui conduisait à une absence de spermatozoïdes dans plus de la moitié des tubes séminifères. Par ailleurs, nos résultats montrent que les taux de testostérone sérique, évalués par un dosage radio-immunologique, étaient diminués du 2ème au 20ème jour de traitement. Ces taux sont, chez les témoins, de 0,717±0,107 ng/ml de sérum; 4,366±0,666 et 1,979±0,42 respectivement à 2j, 10j et 20j. Après traitement par le vanadium, ces taux passent à 0.043±0.012; 2,494±0,17 et 1,086±0,53 respectivement pour les mêmes dates de traitement.Il faut cependant noter que la plupart de ces perturbations morphologiques (poids), histologiques et fonctionnelles (spermatozoïdes immatures, baisse du taux de testostérone) ne sont significatives qu’au début du traitement (2ème au 10ème jour). Du 30ème au 90ème jour, ces perturbations tendent à disparaître, ce qui est en faveur d’un phénomène d’adaptation.L’absorption orale de vanadium chez des rats buvant du thé n’a pas entraîné de modification de la croissance corporelle. Au niveau du tractus génital, seule l’étude histologique a mis en évidence une augmentation modérée de la fréquence de tubes séminifères atrophiés avec absence de spermatozoïdes.Nos résultats sont en faveur d’un effet protecteur du thé vis à vis du vanadium lorsqu’ils sont pris par voie orale. Le thé vert est riche en poly phénols qui peuvent chélater le fer et former des complexes insolubles. Nous suggérons que ces poly phénols peuvent également former avec le vanadium des complexes insolubles qui sont éliminés au niveau des fèces, ce qui pourrait expliquer la diminution et/ou la disparition des effets nocifs du vanadium en présence du thé.AbstractSome heavy metals are known to exert harmful effects by generating an oxidative stress which, in turn, can affect the sexual and reproductive functions of male animals. The addition of antioxidants to the diet could decrease the cytotoxic effect related to oxidative stress (in the presence of heavy metals as food or water contaminants).As a contribution to this problem, the protective effect ofCamellia sinensis green tea, which is know to be rich in antioxidant compounds (polyphenols, etc.), was studied in vanadium-treated adult male rats, with particular attention to growth and genital tract function.White male Wistar rats were given ammonium metavanadate in drinking water (0.46 g/L) for 90 days One group of animals received green tea supplement in drinking water and the control group did not.Chronic vanadium intoxication (without green tea supplement) induced a low growth rate and relative atrophy of the testes, epididymis, prostate and seminal vesicles. Motility and number of spermatozoa were also decreased. Histological examination of the testes revealed atrophy of the seminiferous tubules and defects of spermatogenesis leading to the absence of spermatozoa in 50% of seminiferous tubules. Blood testosterone levels, evaluated by radioimmunoassay, were also decreased from day 2 to day 20. In control animals, these levels were 0.717±0.107 ng/ml; 4.366±0.666 ng/ml and 1.979±0.42 ng/ml on day 2, day 10 and day 20, respectively. After vanadium treatment, they were reduced to 0.043±0.012 ng/ml, 2.494±0.17 ng/ml and 1.086±0.53 ng/ml, respectively, at the same periods.These morphological, histological and functional disorders mostly occured during the first phase of the intoxication period (day 2 to day 10) and were subsequently attenuated, indicating adaptation to the poisoning.In rats receiving green tea, vanadium ingestion did not modify growth rate compared to control animals. Very minor changes were observed in the genital tract. Testicular atrophy and absence of spermatozoa were observed in only some seminiferous tubules.Our results underscore the protective effect of green tea on vanadium poisoning. Polyphenols, which are abundant in green tea, are known to chelate iron. It is proposed that polyphenols may also form insoluble complexes with vanadium, allowing it to be eliminated in the feces. This could explain the decreased effects of vanadium poisoning under our experimental conditions.

Incidences de la restriction calorique et du Nickel sur l'aromatase testiculaire du rat

ResumeDes études épidémiologiques chez l’homme ont montré qu’il existait, depuis 1960, des signes d’augmentation de certaines pathologies génitales masculines. La contamination croissante de l’environnement par des composés chimiques semble être un facteur de causalité. Par ailleurs, divers auteurs avancent l’hypothèse que la restriction calorique a un effet bénéfique sur la reproduction masculine.Ce travail a pour objectif de comparer les effets du nickel sur les processus de reproduction, entre autres l’étude de l’aromatase, chez des rats mâles nourris soit tous les jours, soit un jour sur deux, afin d’évaluer les possibles effets bénéfiques, ou non, d’une restriction calorique sur la fertilité des rats mâles.Dans ce but, nous avons utilisé des rats mâles de souche « Wistar » nourris, soit tous les jours (groupe N), soit un jour sur deux (jeûne intermittent) (groupe J). Après un mois de ce traitement, les rats des deux lots (N) et (J) sont répartis chacun en deux groupes: l’un injecté intra-péritonéalement avec du NaCI 9‰ (groupes NO et JO), l’autre injecté intra-péritonéalement avec du NiCl2 à raison de 4mg/kg (groupes NNi et JNi). Le jeûne intermittent se poursuit parallèlement au traitement par le nickel, et ceci durant 1, 3, 5 et 10 jours.Nous avons choisi pour notre étude comme biomarqueurs sexuels: dosage sérique des oestrogènes, dosage des ARN totaux et l’exploration moléculaire de l’ARNm de l’aromatase testiculaire.L’étude de l’aromatase montre que le nickel seul stimule l’activité de l’aromatase testiculaire et provoque la dégradation des ARN totaux durant le 3èmeet le 10ème jours de traitement.Le jeûne intermittent seul n’induit pas de variations significatives. Dans le cas où le nickel est associé au jeûne intermittent, il semble que pour le taux des ARN totaux testiculaires, l’effet du jeûne l’emporte, pas de dégradation des ARN totaux, d’où ses effets bénéfiques en protégeant les ARN totaux des effets délétères du nickel. On note aussi une surexpression de l’ARNm de l’aromatase vers le 10ème jours de traitement.L’effet hypocalorique du jeûne intermittent pourrait être à l’origine de l’inhibition des effets cytotoxiques du nickel, métal classé parmi les stress oxydants.AbstractThis study was designed to determine whether intermittent fasting induces malnutrition that, according to many authors, accentuates the cytotoxic effects of environmental pollutants, or caloric restriction that reduces these effects.Ninety six male Wistar rats (180g) were divided into two groups: one group was fed daily (N) and the other group was fed every second day (J) for one month. At the end of one month, each group was then divided into two subgroups, one subgroup received an injection of 0.9% NaCI (groups NO and JO), the other subgroup received an injection of 4 mg/kg NiCIb2 (groups NNi and JNi).Intermittent fasting was continued in parallel to treatment for 1, 3, 5 and 10 days.Under these experimental conditions, nickel increased testicular aromatase activity and altered total RNA, while no alteration of these biomarkers was observed with intermittent fasting.The combination of these two factors, nickel and intermittent fasting, did not amplify these effects. In contrast, protection of RNA by intermittent fasting was observed, especially overexpression of aromatase mRNA.