Résumé: Abstract Thyroid hormones play an important role in all tissues of the body, including gonadal function. In Sundevall’s jird, Meriones crassus (Rodentia, Gerbillinea), caught in its natural biotope in the Algerian Sahara Desert, the testis activity was evaluated by testicular and seminal vesicles weights and plasma testosterone level. The thyroid activity was evaluated by plasma concentrations of total triiodothyronine (T3) and thyroxin (T4) using the radioimmunoassay (RIA) method. The testis activity is characterized by a maximum in spring, a regression during summer, a minimum in autumn, and a lower activity in winter. The plasma concentrations of total T3 and T4 varied non-significantly during the seasons. However, thyroid activity varied in contrast to testicular structure, especially during the breeding season when the testis activity is maximum. In order to specify the implication of thyroid function in testis seasonal variations, we investigated the relationship between both activities. This study could further explain the seasonal regulation of testicular function concerning the environmental cues in this jird. Keywords: Plasma T3 and T4, Plasma testosterone, Seasonal variations, Sundevall’s jird

Résumé: Abstract: The Libyan jird (Meriones libycus, 1823) is a wild desert rodent that is a seasonal breeder species adapted to breed when the environmental conditions can satisfy the energy and hydrous requirements of pregnant and nursing females to ensure that births occur at the most favorable time of the year. We assessed gene expression of testicular luteinizing hormone receptor (Lhcgr) correlated to testis activity. The expression of Lhcgr was evaluated using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR and the testis activity by a histological method in adult male Libyan jirds during the nonbreeding and breeding seasons. Our results showed that Lhcgr mRNA expression increased in autumn during the nonbreeding season and decreased in spring during the breeding season. This expression varied in contrast to testicular structure or function and plasma testosterone levels. These results help to elucidate this desert rodent’s seasonal sexual activity, which is correlated with central regulation. Keywords: Libyan jird; mRNA expression; seasons; reproductive cycle; testis Lhcg receptor

Résumé: The molecular mechanisms operating on a seasonal time-scale and regulating functions such as reproduction are poorly understood in animals living in desert environments. Kisspeptin, the product of the KiSS-1 gene, plays a critical role in control of the hypothalamic-pituitary-gonad axis that orchestrates the reproductive system in vertebrates. We report a sequence analysis of KiSS-1 and the pituitary luteinising hormone-beta (LHβ) and follicle-stimulating hormone-beta (FSHβ) in the Libyan jird (Meriones libycus), a seasonal breeding rodent that is sexually active during spring and quiescent in fall. We also assessed gene expression by quantitative real-time reverse transcription-polymerase chain reaction during the non-breeding and breeding seasons. The KiSS-1 cDNA sequence analysis showed high homology between M. libycus and all other rodents (94%) and humans (92%). KiSS-1 expression was higher during the breeding season than that during the non-breeding season. In contrast, LHβ and FSHβ expression levels were higher during the non-breeding season in autumn and varied in an opposite manner with testicular, seminal vesicle weights and plasma testosterone levels. Our results extend the role for KiSS-1 in activating the HPG axis in this desert rodent in its natural biotope by relaying environmental cues as in other seasonal non-desert rodent models.

Résumé: Background: In the context of the valorization of traditional Algerian medicinal plants, the aim of the present study was to compare the different components and the antioxidant activity between the aqueous and methanolic extracts obtained from the leaves of a traditional plant called Suaeda mollis, collected in the district of El Feidh El-Abaid (Khenchela-Algeria). Methods: The two extracts used in this study were obtained by the maceration method, the polyphenols and flavonoids were quantified by spectrophotometric method and the antioxidant activity was evaluated by DPPH assay and FRAP test. Results: Our results showed that the methanolic extract has the highest amount of polyphenols (70.24 mg EAG/g DM) compared to the aqueous extract with (19.30 mg EAG/g DM). The same results were observed. The amount of flavonoids were (96.90 mg EQ/g DM) in the methanolic extract and were (80.67 mg EQ/g DM) in the other extract. The antioxidant results showed that the aqueous extract has a very interesting DPPH free radical scavenging capacity with an IC50 was about 0.39±0.005 mg/mL. These data remain lower than the scavenging capacity of the DPPH radical in the methanolic extract, whose IC50 value was 0.79±0.002 mg/mL. However, in the FRAP assay we found that the iron reducing potential for the methanolic extract is much higher than that of the aqueous extract, which was EC50= 84.71 mg/mL and 434.65 mg/ml) respectively. Conclusion: We can conclude that the aqueous extract of Suaeda mollis collected from the Khenchela-area had a low DPPH radical scavenging capacity and iron reducing potential and a lower amount of polyphenols and flavonoids compared to the methanolic extract. Keywords: Suaeda mollis- Methanolic and aqueous extract- Polyphenols- Flavonoids- DPPH assay- FRAP test.

Résumé: Abstract: The Libyan jird (Meriones libycus, 1823) is a wild desert rodent that is a seasonal breeder species adapted to breed when the environmental conditions can satisfy the energy and hydrous requirements of pregnant and nursing females to ensure that births occur at the most favorable time of the year. We assessed gene expression of testicular luteinizing hormone receptor (Lhcgr) correlated to testis activity. The expression of Lhcgr was evaluated using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR and the testis activity by a histological method in adult male Libyan jirds during the nonbreeding and breeding seasons. Our results showed that Lhcgr mRNA expression increased in autumn during the nonbreeding season and decreased in spring during the breeding season. This expression varied in contrast to testicular structure or function and plasma testosterone levels. These results help to elucidate this desert rodent’s seasonal sexual activity, which is correlated with central regulation. Keywords: Libyan jird; mRNA expression; seasons; reproductive cycle; testis Lhcg receptor

Résumé: The study of both thyroidhormone and receptors, suggested the role of thyroid during acquisition of sexual maturity. Presence of thyroid hormone-β1 receptors has been shown in the cytoplasm of Sertoli cells in the first three months after birth, after presence of these receptors decreased, to be finally absent in adult Sertoli cells [54] . Narrow interrelations were observed between testosterone-receptors and TSH- receptors [54]

Résumé: Abstract : It is now evident that thyroid hormone (TH) plays an important role in the growth and metabolism of individuals. Numerous data show that thyroid hormones affect steroidogenesis and spermatogenesis. Sertoli cells are the units of functional seminiferous tubules that control germ cell development, maturation, and division. The role of triiodothyronine (T3) in supporting the control of cell proliferation and functional maturation is well recognized, as is its role in postnatal Leydig cell differentiation and steroidogenesis. The aim of our work was to detect thyroid receptors (TRs) alpha-1 by immunohistochemistry in male desert rodent the Libyan jird (Meriones libycus) testis during growth. The results show an intense staining of the cytoplasm and Sertoli cells nuclei around the seminiferous tubules during the first three months of animal’s life according to the stage of cell proliferation. However, this coloration is less important and is absent even in prepubertal and adults ; this suggests that thyroid hormones play a role in sexual maturation in male Libyan jird. Key words : Thyroid hormones (THs) receptors- Sertoli cells- growth- Desert rodents

Résumé: La présente étude est une synthèse des travaux effectués sur les variations saisonnières des activités testiculaire et thyroïdienne chez trois de rongeurs déserticoles de la famille des gerbillidés: Gerbillus gerbillus, Meriones crassus (nocturne granivore) et Psammomys obesus (diurne herbivore) et celle de m’actité de reproduction chez Meriones Libycus. Chez ces quatres espèces, l'activité testiculaire a été évaluée par les poids testiculaire et des vésicules séminales et par les tenneurs plasmatique de testostérone. L'activité thyroïdienne a été évaluée par les concentrations plasmatiques de triiodothyronine totale (T3) et de thyroxine (T4), par la méthode de dosage radioimmunologique (RIA) en utilisant des anticorps specifiques. Pour les espèces nocturnes, il existe un cycle saisonnier de la fonction endocrine du testicule, faible au printemps-été et élevé en automne-hiver. Chez l’espèce diurne cette activité est inverse et est elevée en autumn hiver et faible au printemps – été. La fonction thyroïdienne des espèces nocturnes varie dans des proportions faibles et semble active tout au long de l’année alors que celle du rat du sable, espèce diurne, est de moindre activité en autumn- hiver (saison de reproduction) et semble varier en opposition de phase par rapport à celle des testicules; lorsque l'activité testiculaire est maximale, l’activité thyroidienne decline. Sur le plan moléculaire, l’étude a été faite sur Meriones libycus en période de repos et d’activité sexuelle. Nous avons mis en evidence les mécanismes de régulation centrale par la quantification des messagers du kisspeptine hypothalamique, des GTH (FSHβ et LHβ) hypophysaire et de Lhcgr testiculaire par la technique de qPCR-TR en utilisant des amorces spacifiques. En période de reproduction, on observe une diminution de l’expression des gènes des GTH hypophysaires (FSH et LH) en période de repos sexuel et une augmentation en période d'activité repos sexuelle. L’exprression des GTH exerce, un feedback positif sur l’expression des gènes du KiSS-1 en période de reproduction et négatif en période de repos sexuel. L'expression de l'ARNm de Lhcgr est élevée en automne et diminuée au printemps et varie de manière opposée aux structures des testicules et des vésicules séminales qui a été complétée chez Mertiones libycus par une étude histologique qui suivent le même profil que celui des messager du kisspeptine hypothalamique. La causalité des relations unissant les facteurs de l’environement (notamment la photopériode et le régime alimentaire) et les variations saionnières de la fonction de reproduction semblent complexe ; ceci laisse penser que d’autres paramètres , (notamment le GnRH, la leptine, la mélatonine et les oeserogènes….); méritent d’être étudiés afin de mieux comprendre la régulation des variations saionnières de la fonction de reproduction chez les rongeurs déserticles. Mots clés : Messagers de Kispeptine FSHβ LHβ et Lhcgr, Plasma Testostérone; T3 et T4, Rongeurs de desert, Variations saisonnières.