Immunodistribution of RFamide-related peptide-3 (RFRP-3) during the seminiferous epithelium cycle in a desert rodent Psammomys obesus.

The Sand rat, Psammomys obesus, living northwest of the Algerian Sahara, presents a seasonal reproductive cycle. The purposes of this study were firstly to determine the stages of seminiferous epithelium cycle (SEC) by histological and morphometric analysis and secondly to investigate, for the first time, the testicular expression of RFamide-related peptide-3 (RFRP-3) during the SEC by immunohistochemistry. The results showed that the SEC consists of 14 stages according to the tubular morphology method. RFRP-3 was observed in both testicular compartments: the tubular and the interstitial. Leydig cells exhibited the highest RFRP-3 signal (30.73 % ± 4.80) compared to Sertoli cells (13-15 %). In the germline, RFRP-3 was detected during the late prophase I of meiosis in late pachytene, diplotene and metaphasic spermatocytes I. In addition, only round and triangular spermatids were positive during spermiogenesis. Referring to the SEC, it was found that the increased staining of RFRP-3 in spermatocytes I coincided with late pachytene of XI and XII stages (16.90 % ± 0.69 and 16.61 % ± 0.28, respectively). In spermatids, the labeling decreased in the triangular ones at stage IX (8.04 % ± 0.42). These results suggest the involvement of RFRP-3 in the control of SEC in P. obesus.

Kidney functional morphology variations between spring and winter in the Saharan male lizard Uromastyx acanthinura (Sauria, Agamidae), with special reference to body water economy.

To better understand the adaptive mechanisms in Uromastyx acanthinura to the seasonal variations in the arid environment, the present study aimed to explore the kidney functional morphology involved in body water economy. These investigations were carried out by the histological, histochemical and immuno-histochemical methods using conventional light microscopy. The glomeruli number is estimated at 2000 per kidney. The glomeruli size is rather small and decreases significantly in winter. Interestingly, the proximal convoluted tubule (PCT) is long and divided into two different segments which is one of the particularities of this species. Both of the distal convoluted tubule (DCT), connecting tubule (CnT) and collecting duct (CD) epithelium contains mucous cells. The nature and intensity of these mucous secretions vary according to seasons. The evident hypertrophy of the secondary collecting duct (SCD) and tertiary collecting duct (TCD) epithelium is related to the high secretory activity during spring, corresponding to the sexual segment of kidney (SSK). Labeling with anti α-smooth muscle actin-1 showed a thick layer of mucularis surrounded the entire CD. Also, the mesangium of glomeruli contains myofibroblasts. All these renal structural characteristics involved in body water economy may be considered as an adaptive mechanisms of U. acanthinura to resist to dehydration and cope with seasonal variations in the arid environment.

Hyperhomocysteinemia and myocardial remodeling in the sand rat, Psammomys obesus.

OBJECTIVE: Numerous studies have shown that a methionine-rich diet induces hyperhomocysteinemia (Hhcy), a risk factor for cardiovascular diseases. The objective of the present study was to determine the involvement of Hhcy in cardiac remodeling in the sand rat Psammomys obesus. MATERIALS AND METHODS: An experimental Hhcy was induced, in the sand rat Psammomys obesus, by intraperitoneal injection of 300 mg/kg of body weight/day of methionine for 1 month. The impact of Hhcy on the cellular and matricial structures of the myocardium was analyzed with histological techniques (Masson trichrome and Sirius red staining). Immunohistochemistry allowed us to analyze several factors involved in myocardial remodeling, such as fibrillar collagen I and III, metalloproteases (MMP-2 and -9) and their inhibitors (TIMP-1 and -2), TGF-ß1 and activated caspase 3. RESULTS: Our results show that Hhcy induced by an excess of methionine causes, in the myocardium of Psammomys obesus, a significant accumulation of fibrillar collagens I and III at the interstitial and perivascular scales, indicating the appearance of fibrosis, which is associated with an immuno-expression increase of TGF-ß1, MMP-9 and TIMP-2 and an immuno-expression decrease of MMP-2 and TIMP-1. Also, Hhcy induces apoptosis of some cardiomyocytes and cardiac fibroblasts by increasing of activated caspase 3 expression. These results highlight a remodeling of cardiac tissue in hyperhomocysteinemic Psammomys obesus.

Immunohistochemical Localization of Calpains in the Amphibian Xenopus laevis.

Though histochemical techniques have been used for decades, they are still very important in basic research. They make it possible to work on fixed tissues and provide a large amount of information in a relatively short time and at a low cost. Here we describe methods for indirect immunohistochemistry and immunofluorescence on sections of tadpoles and tissues of adult amphibians belonging to the species Xenopus laevis. The objective is to localize calpains within tissues in order to understand their involvement in cellular processes.

Immunolocalization of RFamide-related peptide 3 in a desert rodent Gerbillus tarabuli during seminiferous epithelium cycle.

Gerbillus tarabuli is a nocturnal seasonal breeder desert rodent with a main breeding season in spring and summer, and sexual quiescence in winter. This species is an interesting model for studying testis function in rodents. Therefore, the present study was performed firstly to investigate the stages of seminiferous epithelium cycle of Gerbillus tarabuli with a histological, morphometric and statistical study. And secondly to investigate the expression and possible variations in cellular distribution of RFamide-related peptide-3 (RFRP-3) - the mammalian ortholog of avian gonadotropin-inhibitory hormone (GnIH) - during seminiferous epithelium cycle using immunohistochimestry. Our results showed for the first time that the seminiferous epithelium cycle in Gerbillus tarabuli comprises 14 well-defined stages according to the tubular morphology method. The seminiferous epithelium thickness showed a significant difference during the epithelium cycle, thus it was the only morphometric classification criterion of seminiferous epithelium cycle in Gerbillus tarabuli. The immunohistochemical study reveals, for the first time, the presence of RFRP-3 in Gerbillus tarabuli testes, in both testicular compartments: the tubular and the interstitial. RFRP-3 is expressed differently according to the seminiferous epithelium cycle, RFRP-3 seemed to be more expressed at the stages V-VII and XIII. RFRP-3 was detected in Sertoli cells (≈12%), spermatocytes I (≈19%), round and elongated spermatids (≈13%), and with a more important signal in Leydig cells (26.87%±0.07). These results indicated the importance of RFRP-3 in testicular function in Gerbillus tarabuli; its expression at the interstitial and germinal levels argues in favor of an involvement in androgens synthesis and in spermatogenesis specifically in meiosis and spermiogenesis. This action seems primordial from stages V-VII and XIII. Also, the study of the seminiferous epithelium cycle will enrich the histological identity of the species.

Study of the hydromineral regulation of Typhlonectes compressicauda according to the seasonal variation.

INTRODUCTION: Typhlonectes compressicauda is a viviparous gymnophionan amphibian living in tropical areas of South America. This lengthened amphibian is submitted to seasonal variations characterized by the rainy season (from January to June) and the dry season (from July to December). The mineral homeostasis in amphibians is partly ensured by the neurohormones arginine-vasotocin (AVT), and mesotocin (MST). These two hormones were localized in the hypothalamus, and their receptors, mesotocin receptors (MTR) and vasotocin receptors (VTR2) in the kidney. The aim of the study was to better understand the physiology of the hydromineral regulation of the studied species. MATERIAL AND METHODS: The specimens of T. compressicauda male and female adult were divided into 6 groups: males in the rainy season, males in the dry season, females pregnant in the rainy season, females pregnant in the dry season, females not pregnant in the rainy season, females not pregnant in the dry season. We studied the expression of hormones (AVT, MST) and their receptors (MTR, VTR2) in the hypothalamus and the kidney, respectively, by immunohistochemical and histological techniques. We also studied the expression of aquaporin-2 (AQP2), a water-channel protein in the kidney. RESULTS: We found that the MST (diuretic hormone) and its receptor were more intensively expressed during the rainy season, whereas the period of maximal AVT (anti-diuretic hormone) and VTR2 expression was the dry season. A quantitative analysis showed significant differences in the number of labeled cells in the hypothalamus depending on the seasonal variation. The expression of AQP2 was observed in renal tubules during both seasons with an increased intensity during the dry season. CONCLUSION: The expression of the MST/AVT in brain, their receptors MTRs/VTR2, and AQP2 in kidney changed in T. compressicauda according to the seasonal variations. A direct relationship between the seasonal cycle and reproduction cycle was demonstrated in this species.

Seasonal changes in plasma testosterone and cortisol suggest an androgen mediated regulation of the pituitary adrenal axis in the Tarabul's gerbil Gerbillus tarabuli (Thomas, 1902).

In the desert gerbil Gerbillus tarabuli (Thomas, 1902), cortisol is the main glucocorticosteroid produced by the adrenal glands. Plasma cortisol concentrations show highest values when testosterone is reduced and lowest values during the breeding season which occurs from early winter to late spring. In order to specify the implication of testicular androgens in these corticosteroid seasonal variations we investigated the effects induced by gonadectomy performed during the breeding season on the pituitary adrenal axis. The animals collected in winter were assessed into three groups: sham-operated (Controls; n=13), gonadectomised (GDX; n=13) and testosterone replaced gonadectomised (GDX+T; n=13). Physiological replacement of testosterone enanthate (75µg/100gb.w./twice daily) was applied during one week, while GDX group received the vehicle (40µL sesame oil) alone. The right adrenal glands removed from euthanized animals were fixed for histomorphometry and androgen receptors (ARs) immunohistochemistry and the left ones were frozen with plasma samples until hormonal assays. Gonadectomy induces the enlargement of the adrenal cortex essentially due to that of zonae fasciculata (ZF) and reticularis (ZR) and perimedullary connective tissue which is abundant in the gerbil adrenals. The ARs immunostaining present at both cytoplasmic and nucleus level, is enhanced intensely in the ZR and moderately in the ZF and zona glomerulosa (ZG) cells. GDX group shows reduced plasma ACTH concentration (p=0.0126) by 61% despite the increase in cortisol concentration occurring both in plasma (+216%; p=0.0436) and adrenal tissue (+117%; p=0.0348). Plasma aldosterone is also enhanced significantly (p=0.0147) by 189% but androstenedione synthesis increased in adrenal tissue (p=0.0459) by 65% instead a decrease at circulatory level (p=0.0355) by 58% due to lack of testicular origin. So, testosterone deprivation activates corticosteroidogenesis also evidenced by the adrenal structure changes and the gonadectomy-induced increase in the plasma cholesterol. All of the gonadectomy-induced responses are reversible after physiological testosterone replacement. We conclude that the assessment of circulating adrenocorticotropic hormone (ACTH) concentrations together with cortisol levels essentially, reflecting the hypothalamic-pituitary adrenal (HPA) axis feedback loop control during the annual endogenous changes of testosterone secretion, represents a well-adapted response of this desert species living in an extreme environment.

Seasonal morphophysiological variations in the prostatic complex of the Tarabul's gerbil (Gerbillus tarabuli).

Gerbillus tarabuli is a nocturnal Saharan rodent which has an annual reproductive cycle characterized by the reproductive activity in spring and a long phase of sexual quiescence in other seasons. We describe the morphology and hormonal regulation of the prostatic complex of this rodent in the two periods, based on anatomical, histological, morphometric, and immunohistochemical analyses. The organisation of this prostatic complex is similar to that reported for Meriones unguiculatus, but different from the prostate of Psammomys obesus, the rat, and the mouse. In addition to the anterior lobes, ventral lobes, and dorsal lobes, the prostatic complex of Gerbillus tarabuli, also includes dorsolateral lobe. Each lobe is composed of a fibro-muscular stroma surrounding a glandular epithelium. Dorsolateral lobes are easily distinguishable by their big volume. The prostate grows and regresses cyclically throughout the year. During the resting season, ventral lobes and anterior lobes showed atrophy, with a significant decrease in both epithelial height and supranuclear area size, and a strong thickening of the fibro-muscular compartment. In dorsal lobes, the epithelial and stromal compartments atrophied and regenerated simultaneously, whereas in dorsolateral lobe the thickness of the epithelium, the supranuclear zone and the stroma increased during resting period. Furthermore, seasonal variations were observed in the distribution and expression of both androgen receptors, and estrogens receptors. Expression patterns of all receptors were lobe-specific. In conclusion, both androgens and estrogens are involved in the homeostasis and regulation of the prostate in Gerbillus tarabuli. Dorsolateral lobe seems to be controlled by a different mechanism than other lobes.

Protective effects of probiotic Lactobacillus plantarum BJ0021 on liver and kidney oxidative stress and apoptosis induced by endosulfan in pregnant rats.

Endosulfan (EDS) is one of the most widely organochlorine insecticide used in many parts of the world, although it is currently banned or severely restricted in use in some countries. EDS causes a variety of negative effects in non-target species including humans. Therefore, the aim of the present study was to investigate the possible protective effects of Lactobacillus plantarum BJ0021 on toxicity, oxidative stress, and apoptosis induced by EDS intoxication on liver and kidneys of pregnant rats. This pesticide induced a significant increase in total cholesterol, alanine-amino transferase (ALAT), aspartate-amino transferase (ASAT), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), urea and creatinine in serum, while urinary urea and creatinine were lower than those of the control group. In the liver and kidney, lipid peroxidation increased significantly, the antioxidant levels, such as superoxide dismutase (SOD) and catalase (CAT) were markedly depressed and TdT-mediated dUTP-biotin Nick End Labeling (TUNEL) revealed more apoptotic cells. In contrast, co-administration of L. plantarum BJ0021 to EDS-treated animals ameliorated most of these biochemical parameters, but the activity of antioxidant enzymes (SOD, CAT) did not modify and the number of apoptotic nuclei remained significantly raised in kidney compared to control. In conclusion, the administration of L. plantarum BJ0021 decreased apoptosis and might play a protective role in reducing toxicity of EDS in pregnant rats.

Protective effects of probiotic Lactobacillus plantarum BJ0021 on liver and kidney oxidative stress and apoptosis induced by endosulfan in pregnant rats.

Endosulfan (EDS) is one of the most widely organochlorine insecticide used in many parts of the world, although it is currently banned or severely restricted in use in some countries. EDS causes a variety of negative effects in non-target species including humans. Therefore, the aim of the present study was to investigate the possible protective effects of Lactobacillus plantarum BJ0021 on toxicity, oxidative stress, and apoptosis induced by EDS intoxication on liver and kidneys of pregnant rats. This pesticide induced a significant increase in total cholesterol, alanine-amino transferase (ALAT), aspartate-amino transferase (ASAT), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), urea and creatinine in serum, while urinary urea and creatinine were lower than those of the control group. In the liver and kidney, lipid peroxidation increased significantly, the antioxidant levels, such as superoxide dismutase (SOD) and catalase (CAT) were markedly depressed and TdT-mediated dUTP-biotin Nick End Labeling (TUNEL) revealed more apoptotic cells. In contrast, co-administration of L. plantarum BJ0021 to EDS-treated animals ameliorated most of these biochemical parameters, but the activity of antioxidant enzymes (SOD, CAT) did not modify and the number of apoptotic nuclei remained significantly raised in kidney compared to control. In conclusion, the administration of L. plantarum BJ0021 decreased apoptosis and might play a protective role in reducing toxicity of EDS in pregnant rats.