Evidence of melatonin ameliorative effects on the blood-testis barrier and sperm quality alterations induced by cadmium in the rat testis.

Herein, we further document the protective action of melatonin (MLT) in mitigating cadmium (Cd)-induced toxicity on male adult rat testis. Cd treatment provoked testicular injury, that was documented by histological and biomolecular alterations, i.e., decrease of serum and testicular testosterone concentration and modified sperm parameters. Mainly, both the cytoarchitecture of the blood-testis barrier (BTB) and germ cell morphology were perturbed, as highlighted by impairment in structural (OCN, VANGL, Cx43) and regulative (Src and FAK) protein levels and/or activation. The study focused on the involvement of the autophagy pathway, that was enhanced especially in the Sertoli cells, probably in response to the disorganization of the BTB. Results obtained with the MLT co-treatment demonstrated that its administration decreased the level of oxidative damage caused by Cd, with reversal of all the observed changes. Moreover, the beneficial effects of MLT alone were evidenced by an increase of sperm quality, in term of motility and DNA integrity. The combined results, obtained in rat, strongly encourage to consider a role for MLT in improving also human testicular health, not only in men exposed to Cd, but also in those having fertility disorders, to ameliorate sperm quality and, consequently, reproductive success

Altered Expression of DAAM1 and PREP Induced by Cadmium Toxicity is Counteracted by Melatonin in the Rat Testis.

Cadmium (Cd) is one of the most toxic pollutants for health due to its accumulation in several tissues including testis. This report confirms that Cd increased oxidative stress and apoptosis of germ and somatic cells, provoked testicular injury, as documented by biomolecular and histo-logical alterations, i.e., CAT and SOD activity, the protein level of steroidogenic enzymes (StAR and 3β-HSD), and morphometric parameters. Additionally, it further documents the melatonin (MLT) coadministration effects in mitigating Cd-induced toxicity on adult rat testis, as demon-strated by the reduction of oxidative stress and apoptosis, with reversal of the observed histolog-ical changes; moreover, a role of MLT in partially restoring steroidogenic enzymes expression was evidenced. Importantly, the cytoarchitecture of testicular cells was perturbed by Cd exposure, as highlighted by impairment of the expression and localization of two cytoskeleton-associated proteins DAAM1 and PREP, involved in the germ cells differentiation into spermatozoa, altering the normal spermatogenesis. Here, for the first time, we found that the co-treatment with MLT at-tenuated the Cd-induced toxicity on the testicular DAAM1 and PREP expression. The combined findings provide additional clues about a protective effect of MLT against Cd-induced testicular toxicity, acting on DAAM1 and PREP expression, encouraging further studies to prove its effec-tiveness in human health

Variability of antioxidant and biological activities of Rhus tripartitum related to phenolic compounds

Rhus species are known in traditional medicine for their therapeutic virtue and their extracts showed numerous important properties including antimalarial, antimicrobial, antiviral, and hypoglycemic and anticonvulsant activi- ties. Rhus tripartitum (Ucria) is a medicinal plant widely used in Tunisia folk medicine against chronic diarrhea and gastric ulcer. This study was designed to examine in vitro and ex vivo antioxidant, anti-inflammatory and anticancer activities of four extracts of Rhus tripartitum root cortex with increasing solvent polarity (hexane, di-chloromethane, methanol and water). HPLC was used to identify and quantify phenolic compounds in Rhus ex- tract. Water extract showed the highest antioxidant activity using oxygen radical absorbance capacity (ORAC method) with 8.95 ± 0.47 µmol Trolox/mg and a cell based-assay with 0.28 ± 0.12 µmol Trolox/mg as compared to the other fractions. Moreover, methanol extract displayed the strongest anti-cancer activity against human lung carcinoma (A-549) and colon adenocarcinoma cell lines (DLD-1) with an IC50 value of 60.69 ± 2.58 and 39.83 ± 4.56 µg/ml (resazurin test) and 44.52 ± 5.96 and 55.65 ± 6.00 µg/ml (hoechst test), respectively. Besides, the highest anti-inflammatory activity, inhibiting nitric oxide (NO) release, was exhibited by dichloromethane extract with 31.5 % at 160 µg/ml in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. The HPLC analysis showed that catechol and kaempferol were the major phenolics. These data suggest the richness of all fractions of les with different polarity and confirm the known traditional therapeutics virtues of this species for the treatment of dysentery, diarrhea and gastric ulcer

Identification des principaux déterminants environnementaux et modélisation de la distribution potentielle de pin d’Alep et impact du changement climatique en Tunisie

The distribution of forest ecosystems in Mediterranean region are largely under the influence of environmental conditions such as climate and orographic parameters. This study aimed to understand the relationship between Aleppo pine (Pinus halepensis Mill.) occurrences and environmental conditions at a regional scale in Tunisia. However, it is important to mention another type of threat that is likely to trouble this forest ecosystem in the future; these are the consequences of climate change. In this study, the Maxent software, based on sample point of the Aleppo pine and the environment variables was used to model the current distribution and to predict the impact of climate change. The model developed showed good predictivity with AUC > 0.90 indicated the prediction model’s high credibility and accuracy. Furthermore, we examined the variable importance and contribution to the prediction results, to distinguish the effect of different variables on the potential distribution area. The results showed that the variables relevant to Aleppo pine distribution area are precipitation, altitude, slope and temperature Annual Range. To investigate the potential effects of climate change on the target species, we used Maxent modeling algorithm for two representative concentration pathways, lower emission scenario (RCP 2.6) and higher emission (RCP 8.5) climate scenarios in 2050 and 2070. A comparison of the current vegetation cover with the current potential distribution highlights a fragmentation of the natural habitat of the Aleppo pine in Tunisia. Indeed, the current species distribution represents only 25% of its suitable area. Human activities had induced severe changes in the natural Aleppo pine forest ecosystems. Future predictions expect an extension of the areas classified as favorable to the Aleppo pine. In response to climate changes, the Aleppo pine may display two contrasted tendencies: a progressive evolution in the north, and a regressive evolution in the southern limit. However, the expansion of suitable areas may be more important than loss of habitat suitability. The future climate could convert areas that are currently not suitable for Aleppo pine (humid sub-humid) into very suitable. Keywords: Aleppo pine, climate and orographic parameters, climate change, Maxent, TunisiaLa répartition géographique des écosystèmes forestiers méditerranéens est largement influencée par les conditions du milieu notamment les paramètres climatiques et orographiques. Cet article porte sur  l’étude des variables influençant la répartition spatiale du pin d’Alep à l échelle de la Tunisie. Cependant, il est important de mentionner un autre type de menaces qui risque bien de bouleverser, à l’avenir, de cet écosystème  forestier, ce sont les impacts liés aux changements climatiques. Dans cette étude, le développement d’un modèle à l’échelle de l’aire de pin d’Alep par combinaison des variables environnementales et des points de présence de l’espèce selon le principe d’entropie maximale, a permis, de connaitre les principales variables responsables de sa distribution, ainsi, de cartographier la répartition potentielle des pinèdes sous les conditions climatiques actuelles et futures. Le modèle développé avec Maxent a montré une bonne prévisibilité avec une AUC > 0,9. Les résultats ont montré que les précipitations annuelles, l’altitude, la pente et l’amplitude thermique semble être les principaux facteurs de la distribution spatio-temporelle du pin d'Alep dans la zone d’étude. Une comparaison de la couverture végétale actuelle avec la répartition potentielle actuelle met en évidence une fragmentation de l’habitat naturel de cette espèce conifère. En effet, l’aire de répartition actuelle ne représente que 25% de l’habitat favorable à cette espèce. Conséquences de l'action de l'homme sur son environnement. Cependant, la simulation de cette aire potentielle de distribution de l’espèce selon deux scénarios de réchauffement RCP2.6 et RCP8.5, aux horizons 2050 et 2070, permet d’évaluer et de cartographier l’impact potentiel du changement climatique sur le pin d’Alep. Ainsi, les distributions futures semblent être affectées par le climat futur. En réponse aux changements climatiques, le pin d'Alep peut présenter deux tendances contrastées. Une évolution progressive dans le nord et une évolution régressive dans sa limite inférieure. Cependant, l’expansion des aires favorables pourrait être plus importante qu’un rétrécissement. Le climat futur pourrait convertir les zones qui sont actuellement peu favorables au pin d’Alep (subhumides humides) en zones très favorables. Mots clés: Pin d’Alep, paramètres climatique et orographiques, changement climatique, Maxent, Tunisie  &nbsp

Combined effect of polystyrene microplastics and cadmium on rat blood‑testis barrier integrity and sperm quality

The harmful effects of microplastics and Cd on the testicular activity of sexually mature rats are here documented. Oral treatment with both substances caused testicular impairment that was evidenced by histological and biomolecular alterations, such as MP accumulation in the seminiferous epithelium, imbalance of oxidative status, and reduced sperm quality. Importantly, the cytoarchitecture of the blood-testis barrier was compromised, as revealed by the down-regulation of protein levels of structural occludin, Van Gogh-like protein 2, and connexin 43 and activation of regulative kinases proto-oncogene tyrosine-protein kinase and focal adhesion kinase. Interestingly, for the first time, MPs are reported to activate the autophagy pathway in germ cells, to reduce damaged organelles and molecules, probably in an attempt to avoid apoptosis. Surprisingly, the results obtained with the simultaneous Cd + MPs treatment showed more harmful effects than those produced by MPs alone but less severe than with Cd alone. This might be due to the different ways of administration to rats (oral gavage for MPs and in drinking water for Cd), which might favor the adsorption, in the gastrointestinal tract, of Cd by MPs, which, by exploiting the Trojan horse effect, reduces the bioavailability of Cd

Effect of crop management on soil bacterial communities in organic and conventional farming systems. Elabed, N., Bouri, M., Rhouma, A., Ben Kheder, M., and M'Hamdi, M. (Tunisia)

The aim of the present study was to assess the population of bacteria isolated from organic and conventional soils and to identify antagonistic ones with a potential antifungal activity against some pathogenic fungi (Rhizoctonia solani and Fusarium oxysporum). All cultivable bacterial isolates were evaluated for their antifungal activity and the most effective ones were identified based on 16S rDNA sequence analysis. The results showed that among a total number of 100 bacteria isolated from soil, eight isolates displayed antifungal activity against F. oxysporum and twenty four isolates had suppressed R. solani growth. The results indicated that tested bacterial species exhibited varying degree of antagonistic potential against pathogenic fungi which ranged from 22.7% using AB95 isolate to 77.2% with AB40 and AB8 tested against F. oxysporum and from 22.7% using AB51 and AB5 to 68.1% with AB75 and AB64 tested against R. solani. DNA sequencing reaction of purified PCR amplicon was carried out using 16sF and 16sR primers. Sequence alignment with the reference sequences of the databases using BLAST was performed. The most dominant genuswas Bacillus. Phylogenetic tree was built

Expression of RSPH6A in the first wave of rat spermatogenesis and oxidative stress conditions: Attenuation by melatonin.

Purpose: Here, we report, for the first time, the temporal expression and localization of axonemal radial spoke head homolog A (RSPH6A) protein during the first wave of rat spermatogenesis and in oxidative stress conditions. Methods: For the developmental study, testes were collected from rats at different developmental stages (7, 14, 21, 28, 35, 42, and 60 postnatal days); for in vivo treatment, 24 rats were treated with cadmium and/or melatonin. From each sample, western blot (WB) and immunofluorescence (IF) analyses for RSPH6A were performed. Results: RSPH6A expression starts at 21 PND alongside the appearance of I spermatocytes (SPC) with a significant increase up to 60 PND. Data were confirmed by IF analysis, showing that RPSH6A expression is restricted to I and II SPC, spermatids, and mature sperm. In vivo experiments showed that the expression and localization of RSPH6A in the testis and epididymal spermatozoa of adult rats treated with cadmium were impaired. Interestingly, melatonin (an antioxidant), given together with Cd, can counteract its damaging effects. Conclusions: All combined data confirm that RSPH6A contributes to the onset of fertility by acting on sperm motility, raising the possibility of using RSPH6A as a marker for normal fertility in the general population

Steroidogenesis Upregulation through Mitochondria-Associated Endoplasmic Reticulum Membranes and Mitochondrial Dynamics in Rat Testes: The Role of D-Aspartate

Mitochondria-Associated Endoplasmic Reticulum Membranes (MAMs) mediate the communication between the Endoplasmic Reticulum (ER) and the mitochondria, playing a fundamental role in steroidogenesis. This study aimed to understand how D-aspartate (D-Asp), a well-known stimulator of testosterone biosynthesis and spermatogenesis, affects the mechanism of steroidogenesis in rat testes. Our results suggested that D-Asp exerts this function through MAMs, affecting lipid trafficking, calcium signaling, ER stress, and mitochondrial dynamics. After 15 days of oral administration of D-Asp to rats, there was an increase in both antioxidant enzymes (SOD and Catalase) and in the protein expression levels of ATAD3A, FACL4, and SOAT1, which are markers of lipid transfer, as well as VDAC and GRP75, which are markers of calcium signaling. Additionally, there was a decrease in protein expression levels of GRP78, a marker of aging that counteracts ER stress. The effects of D-Asp on mitochondrial dynamics strongly suggested its active role as well. It induced the expression levels of proteins involved in fusion (MFN1, MFN2, and OPA1) and in biogenesis (NRF1 and TFAM), as well as in mitochondrial mass (TOMM20), and decreased the expression level of DRP1, a crucial mitochondrial fission marker. These findings suggested D-Asp involvement in the functional improvement of mitochondria during steroidogenesis. Immunofluorescent signals of ATAD3A, MFN1/2, TFAM, and TOMM20 confirmed their localization in Leydig cells showing an intensity upgrade in D-Asp-treated rat testes. Taken together, our results demonstrate the involvement of D-Asp in the steroidogenesis of rat testes, acting at multiple stages of both MAMs and mitochondrial dynamics, opening new opportunities for future investigation in other steroidogenic tissues

Evidence of the protective role of D-Aspartate in counteracting/preventing cadmium-induced oxidative stress in the rat testis

Cadmium (Cd), by producing oxidative stress and acting as an endocrine disruptor, is known to cause severe testicular injury, documented by histological and biomolecular alterations, such as decreased serum testosterone (T) level and impairment of spermatogenesis. This is the first report on the potential counteractive/preventive action of D-Aspartate (D-Asp), a well-known stimulator of T biosynthesis and spermatogenesis progression by affecting hypothalamic-pituitary-gonadal axis, in alleviating Cd effects in the rat testis. Our results confirmed that Cd affects testicular activity, as documented by the reduction of serum T concentration and of the protein levels of steroidogenesis (StAR, 3β-HSD, and 17β-HSD) and spermatogenesis (PCNA, p-H3, and SYCP3) markers. Moreover, higher protein levels of cytochrome C and caspase 3, together with the number of cells positive to TUNEL assay, indicated the intensification of the apoptotic process. D-Asp administered either simultaneously to Cd, or for 15 days before the Cd-treatment, reduced the oxidative stress induced by the metal, alleviating the consequent harmful effects. Interestingly, the preventive action of D-Asp was more effective than its counteractive effect. A possible explanation is that giving D-Asp for 15 days induces its significant uptake in the testes, reaching the concentrations necessary for optimum function. In summary, this report highlights, for the first time, the beneficial role played by D-Asp in both counteracting/preventing the adverse Cd effects in the rat testis, strongly encouraging further investigations to consider the potential value of D-Asp also in improving human testicular health and male fertility