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Seminiferous Tubule Diameter (seminiferous + tubule_diameter)
Selected AbstractsReproductive seasonality in the Tete veld rat (Aethomys ineptus) (Rodentia: Muridae) from southern AfricaJOURNAL OF ZOOLOGY, Issue 2 2006S. P. Muteka Abstract Very little is known about the reproductive biology of the recently recognized Tete veld rat Aethomys ineptus. In the present study, we investigated the seasonality of reproduction in this newly recognized rodent using a number of histological and endocrinological parameters. Body mass, reproductive tract morphometrics, gonadal histology, and plasma testosterone concentrations in males and plasma oestradiol-17, and progesterone concentrations in females were assessed from a population in the north-central part of South Africa over a 12-month period in order to ascertain the pattern of reproduction in the species. Seminiferous tubule diameters in 59 males were significantly larger between September and February relative to between March and August. Although spermatogenesis was prevalent in the southern hemisphere winter (June,August), the number of spermatozoa in the epididymides decreased in the southern hemisphere spring (September,November), summer (December,February) and autumn (March,May). Testicular mass relative to body mass and testicular volume regressed between May and September but exhibited recrudescence between September and April, whereas plasma testosterone concentrations increased significantly between September and February relative to between March and August. Ovarian histology of 67 females showed corpora lutea to be present throughout the year, but decreased in number during winter, whereas mean plasma progesterone concentration increased significantly between August and November and again between February and April. This bimodal pattern of progesterone concentration suggests that up to two litters per breeding season may be raised by the Tete veld rat. Gravid females were found between October and April, whereas gravid or lactating females were conspicuously absent between May and September. Collation of all these data suggests that the Tete veld rat is a seasonal breeder with reproduction confined predominantly to summer and autumn months of the southern hemisphere. However, the presence of follicular development in females and the presence of corpora lutea outside the breeding season imply that the Tete veld rat may undergo spontaneous ovulation. [source] Infancy is not a quiescent period of testicular developmentINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2001Héctor E. Chemes Postnatal evolution of the testis in most laboratory animals is characterized by the close continuity between neonatal activation and pubertal development. In higher primates, infancy, a long period of variable duration, separates birth from the beginning of puberty. This period has been classically considered as a quiescent phase of testicular development, but is actually characterized by intense, yet inapparent activity. Testicular volume increases vigorously shortly after birth and in early infancy due to the growth in length of seminiferous cords. This longitudinal growth results from active proliferation of infantile Sertoli cells which otherwise display a unique array of functional capabilities (oestrogen and anti-müllerian hormone secretion, increase of FSH receptors and maximal response to FSH). Leydig cells also show recrudescence after birth, possibly determined by an active gonadotrophic-testicular axis which results in increased testosterone secretion of uncertain functional role. This postnatal activation slowly subsides during late infancy when periodic phases of activation of the hypothalamo-pituitary-testicular axis are paralleled by incomplete spermatogenic spurts. The beginning of puberty is marked by the simultaneous reawakening of Leydig cell function and succeeding phases of germ cell differentiation/degeneration which ultimately lead to final spermatogenic maturation. The marked testicular growth in this stage is due to progressive increase at seminiferous tubule diameter. Sertoli cells, which have reached mitotic arrest, develop and differentiate, establishing the seminiferous tubule barrier, fluid secretion and lumen formation, and acquiring cyclic morphological and metabolic variations characteristic of the mature stage. All of these modifications indicate that, far from being quiescent, the testis in primates experiences numerous changes during infancy, and that the potential for pubertal development and normal adult fertility depends on the successful completion of these changes. [source] Effect of growth hormone on testicular dysfunction induced by methotrexate in ratsANDROLOGIA, Issue 2 2009H. Serati Nouri Summary Methotrexate (MTX) is a chemotherapeutic agent causing defective oogenesis and spermatogenesis. This study was performed to assess the role of human growth hormone (GH) on testis recovery after treatment with MTX. Forty male Wistar rats were selected and randomly divided into four groups (n = 10): control (vehicle), GH group (0.3 mg kg,1 GH for 28 days, IP), MTX group (MTX 1 mg kg,1 week,1 for 4 weeks, IP) and GH/MTX group (0.3 mg kg,1 GH for 28 day plus 1 mg kg,1 week,1 MTX for 4 weeks, IP). On days 14 and 28, five rats from each group were killed, testes of rats of all groups were removed, spermatozoa were collected from epididymis and then prepared for analysis. MTX caused significant increase in interstitial tissue and capsular thickness and decrease of testicular and body weight (P < 0.05). Moreover, it caused significant decline in seminiferous tubule diameter and epithelium thickness (P < 0.05). There was no obvious change in morphometrical parameters between MTX/GH and control groups. In MTX group, sperm parameters decreased significantly (P < 0.05). Administration of GH plus MTX reduced the effects of MTX on sperm parameters and testosterone concentration. These results suggested that GH had a protective effect on almost all destructive effects caused by MTX in rat testes and thus improved sperm parameters. [source] Protective effect of L -carnitine on testicular ischaemia,reperfusion injury in rats,CELL BIOCHEMISTRY AND FUNCTION, Issue 6 2007Dikmen Dokmeci Abstract Testicular torsion is a urological emergency referred to as ,acute scrotum', because inappropriate treatment can lead to male subfertility and infertility. A possible cause of testicular damage is the ischaemia,reperfusion (I/R) injury attributed to oxygen free radicals. L -carnitine, a vitamin-like antioxidant, plays a pivotal role in the maturation of spermatozoa within the reproductive tract. The aim of the present paper was to determine the protective effect of L -carnitine on testicular I/R-induced injury. Thirty-two male rats were divided into 4 groups (n,=,8). Testicular torsion was created by rotating the right testis 720° in a clockwise direction. Group 1: sham-operated control; group 2: ischaemia; group 3: I/R; group 4: ischaemia,L -carnitine treatment,reperfusion group. L -carnitine (500,mg,kg,1, intraperitoneally) was administered before 30 min of detorsion in Group 4. After torsion (5,h) and detorsion (5,h), bilateral orchidectomy was performed. The malondialdehyde (MDA) level was evaluated in testes. Histopathologically, Johnsen's spermatogenesis criteria and mean seminiferous tubule diameter (MSTD) measurements were used. Testicular MDA levels were higher in the torsion group compared to the sham-control group (p,<,0.05). Detorsion (reperfusion) caused a further increase in MDA levels (p,<,0.05). Pretreatment with L -carnitine prevented a further increase in MDA levels (p,<,0.05). Histologically, torsion caused some separation among germinal cells in the seminiferous tubules, which became much more prominent in the I/R group but was attenuated with L -carnitine pretreatment. In conclusion, L -carnitine pretreatment may have a protective effect in experimental testicular torsion,detorsion model in rats by its well-known antioxidant potential. Copyright © 2006 John Wiley & Sons, Ltd. [source] ROSIGLITAZONE, AN AGONIST OF PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR-GAMMA, PREVENTS CONTRALATERAL TESTICULAR ISCHAEMIA,REPERFUSION INJURY IN PREPUBERTAL RATSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2007Mustafa Inan SUMMARY 1Rosiglitazone plays a positive role in the reparation of ischaemia,reperfusion (I/R) injury in different tissues. Thus, we examined its biochemical and histological effects on the contralateral testes to determine whether exogenous rosiglitazone affords any protection against testicular damage. 2Forty-eight prepubertal male Wistar-Albino rats were divided into six groups. Testicular torsion was created by rotating the right testis 720° in a clockwise direction for 5 h in all groups except group I, which was the sham-control group. In group II, bilateral orchiectomy was performed following the torsion period. After detorsion both testes were removed in the fifth hour in group III and on the seventh day in group IV. In group V, one-shot rosiglitazone (4 mg/kg) was administered 40 min before detorsion and both testes were removed following the torsion period. In group VI, rosiglitazone was administered (4 mg/kg) 40 min before detorsion and for 7 days, and then both testes were harvested. The tissue levels of malondialdehyde (MDA) were measured and mean testicular biopsy score (MTBS) and mean seminiferous tubule diameter (MSTD) were examined. Immunoexpression of endothelial nitric oxide synthase (eNOS) in testes tissues was investigated by immunohistochemical studies. 3In the contralateral testis, the MTBS and MSTD values of group VI were significantly higher than those in group IV. Immunohistochemically, mild eNOS immunostaining was present in the germ cells of the contralateral testes in group IV after I/R. In group VI, intense eNOS immunoreactivity was seen in the contralateral testes. 4Rosiglitazone reduces contralateral testicular damage formed after unilateral testicular torsion and alleviates the oxidative events. [source] Leptin and varicocele-related spermatogenesis dysfunction: animal experiment and clinical studyINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 5 2009Bin Chen Summary The objective of this study was to explore the relationships between varicocele-related spermatogenesis dysfunction and the expression of leptin and leptin receptors. In rats with experimental varicocele, the function of spermatogenesis, the expression of leptin and leptin receptors in testes were analysed; and in patients with varicocele-related male infertility, serum and seminal plasma levels of leptin, gonadal hormones and semen parameters were evaluated. In the testes of rats, leptin was expressed in seminiferous tubules and intersitium, leptin receptor was predominantly expressed in interstitium. The expression of leptin and its receptor in the testis of rats was not related to the weight of rat, but was inversely related to the weight of testis (r = ,0.408, p = 0.009 and r = ,0.433, p = 0.005, respectively), the Johnsen scores (r = ,0.916, p = 0.000 and r = ,0.863, p = 0.000, respectively), the seminiferous tubules diameter (r = ,0.853, p = 0.000 and r = ,0.870, p = 0.000, respectively) and the thickness of seminiferous epithelium (r = ,0.929, p = 0.000 and r = ,0.948, p = 0.000, respectively). In varicocele patients (N = 40), the sperm concentration and motility were significantly lower (p = 0.000) than those in the control group (N = 25), and the leptin level in seminal plasma was significantly higher (p = 0.000) than that in the control group. The leptin in serum and seminal plasma was positively related (r = 0.223, p = 0.002). The seminal plasma leptin level was inversely related to sperm concentration (r = ,0.632, p = 0.000) and motility (r = ,0.635, p = 0.000). There was no significant relation between serum leptin and seminal parameters and between leptin and gonadal hormone values. The dysfunction of spermatogenesis in varicocele-related infertile male is associated with increase in leptin and leptin receptors. Leptin may have local effects on the function of testis and spermatogenesis. [source] | |||||||||||||