Spermatogenic Activity Research Articles

Reproductive biology of the Amazon Lava Lizard (Tropidurustorquatus) from the Wet Chaco of Corrientes (Argentina): congeneric comparisons of ecotypic and interspecific variations

Herein we describe the reproductive biology of a population of the Amazon Lava Lizard (Tropidurus torquatus (Wied-Neuwied, 1820)) from Corrientes, northeastern Argentina (Wet Chaco). We describe the male and female reproductive cycles, minimum body size for adults, reproductive output, mean relative clutch mass, fat body cycles, and sexual dimorphism. Our results were compared with data on the reproductive biology of Brazilian populations of T. torquatus and congeneric species. In Corrientes, males of T. torquatus exhibited a continuous reproductive cycle, but with annual variation of testicular parameters associated with spermatogenic activity. In contrast, females were reproductive only from winter to summer (July–February), laying at least two clutches each of six eggs, on average, per reproductive season. The relative clutch mass and egg size values in Corrientes were the highest reported for the species. The annual cycle of energy storage (as fat bodies) was inversely correlated with reproductive activity in both sexes. Males differed from females in snout–vent length, head size, interlimb length, and tail length. We observed interpopulational differences in relative clutch mass, egg volume and mass, incubation period and hatching time, and the minimum body size for sexual maturity probably as a result of phenotypic plasticity or adaptation to local environmental conditions and likely both.

The structure, morphometry and vascular perfusion of the testis in the rufous sengi (Elephantulus rufescens)

Abstract Introduction and Materials and Methods: Sengis are testicondid, monogamous afrotherian mammals. The testes, pattern of testicular blood vessels and anatomical disposition of caudal vena cava were examined macroscopically in the rufous sengi (Elephantulus rufescens). Testicular structure was further studied microscopically and its components quantified using stereology. Results: The testes were cylindrical in shape and located caudolateral to the kidneys. The testicular arteries branched from renal arteries, ran to the respective testicles without close association with other vessels, while the veins ran straight to the caudal vena cava without pampiniform plexus or intimate association with cognate arteries. There were two caudal vena cavae that united after receiving the renal veins. The seminiferous tubules were bound by a peritubular boundary tissue with a single layer of myoid cells while the interstitial tissue had polyhedral or elongate Leydig cells and connective tissue elements. The testicular volume was estimated at 0.089 ± 0.0031 cm3 with the seminiferous tubules (mean diameter = 210 ± 5.7 μm) constituting 89.4 ± 0.8% of its volume and tubulosomatic index of 0.38%. The interstitial tissue and tunica albuginea constituted 8.9 ± 0.81% and 1.7 ± 0.1% of the testis volume respectively. Conclusion: The testis exhibited general mammalian features while its vascular pattern was simple without indications of a role in testicular thermoregulation as is the case for other afrotherians. The investment of body mass in seminiferous tubules suggests a spermatogenic activity higher than expected in monogamous animals. The double caudal vena cava could be a result of retention of the left supracardinal vein to adulthood.

Angiogenesis inhibition impairs testicular morphology in experimental left varicocele rat model

IntroductionIt has been reported that varicocele might promote angiogenesis. However, it is not clearly identified how angiogenesis affect testicular morphology or spermatogenic activity. The objective of the study is to investigate the effect of spironolactone, as an angiogenesis inhibitor, on the ipsilateral testis morphology in left varicocele-induced rats. Materials and methodsTwenty-four adult (12–14 mo), male Wistar albino rats were randomly assigned to four groups (n=6, for each): 1. Control group, 2. Sham-operated group, 3. Experimental left varicocele group and, 4. Spironolactone (20mg/kg/day)-treated experimental left varicocele group. Histopathological findings in rat testis were investigated. ResultsMicrovessel density increased in varicocele group and spironolactone inhibited angiogenesis neither by antimineralocorticoid, nor by antiandrogenic effect. However, spermatogenesis impaired in spironolactone treated varicocele group. ConclusionAngiogenesis seems to be a protective process in varicocele. Spironolactone treatment, probably by inhibiting angiogenesis, impairs testicular morphology.

Seasonal spermatogenesis in the Mexican endemic oviparous lizard, Sceloporus aeneus (Squamata: Phrynosomatidae).

Oviparous species of Sceloporus exhibit either seasonal or continuous spermatogenesis and populations from high-elevation show a seasonal pattern known as spring reproductive activity. We studied the spermatogenic cycle of a high-elevation (2700m) population of endemic oviparous lizard, Sceloporus aeneus, that resided south of México, D.F. Histological analyses were performed on the testes and reproductive ducts from individual lizards collected monthly. This population of S. aeneus showed a seasonal pattern of spermatogenesis, with 4 successive phases common in other lizards. These include: 1) Quiescence in August, which contained solely spermatogonia and Sertoli cells; 2) Testicular recrudescence (September-January) when testes became active with mitotic spermatogonia, spermatocytes beginning meiosis, and the early stages of spermiogenesis with spermatids; 3) Maximum testicular activity occurred from March to May and is when the largest spermiation events ensued within the germinal epithelia, which were also dominated by spermatids and spermiogenic cells; 4) Testicular regression in June was marked with the number of all germs cells decreasing rapidly and spermatogonia dominated the seminiferous epithelium. February was a transitional month between recrudescence and maximum activity. The highest sperm abundance in the lumina of epididymides was during maximum testicular activity (March-May). Thus, before and after these months fewer spermatozoa were detected within the excurrent ducts as the testis transitions from recrudescence to maximum activity in February and from maximum activity to quiescence in June. Maximum spermatogenic activity corresponds with warmest temperatures at this study site. This pattern known as spring reproductive activity with a fall recrudescence was similar to other oviparous species of genus Sceloporus.

La inhibición de la angiogénesis deteriora la morfología testicular en modelo de rata con varicocele izquierdo experimental

IntroductionIt has been reported that varicocele might promote angiogenesis. However, it is not clearly identified how angiogenesis affect testicular morphology or spermatogenic activity. The objective of the study is to investigate the effect of spironolactone, as an angiogenesis inhibitor, on the ipsilateral testis morphology in left varicocele-induced rats. Materials and methodsTwenty four adult (12-14 mo), male Wistar albino rats were randomly assigned to four groups (n=6, for each): 1. Control group, 2. Sham-operated group, 3. Experimental left varicocele group and, 4. Spironolactone (20mg/kg/day)-treated experimental left varicocele group. Histopathological findings in rat testis were investigated. ResultsMicrovessel density increased in varicocele group and spironolactone inhibited angiogenesis neither by antimineralocorticoid, nor by antiandrogenic effect. However, spermatogenesis impaired in spironolactone treated varicocele group. ConclusionAngiogenesis seems to be a protective process in varicocele. Spironolactone treatment, probably by inhibiting angiogenesis, impairs testicular morphology.

Toxicopathological Alterations Induced by High Dose Dietary T-2 Mycotoxin and its Residue Detection in Wistar Rats

T-2 toxin is one of the most potent cytotoxic and food-borne mycotoxins. Most experimental studies on the T-2 toxin have been performed at extremely low doses (ppb level). However, several field reports of contaminated feed have shown concentration of T-2 toxin to be as high as ≥20ppm. Therefore, the impact of high dose T-2 toxin (20ppm) after subacute exposure was investigated in an experimental setup with respect to growth performance, oxidative stress, and detailed pathomorphology in young male Wistar rats. Furthermore, to see the effect of such a high dose on the accumulation of T-2 toxin, its residues in various organs were quantified by high-performance thin-layer chromatography (HPTLC). Apart from obvious clinical toxicosis, rats in the toxin-fed group showed significant hemato-biochemical alterations and increased levels of biological markers of oxidative stress with concomitant decrease in levels of serum and tissue catalase and superoxide dismutase. These alterations were strongly supported by histopathological changes, such as hyperkeratosis and hyperplasia of the squamous gastric mucosa, oxidative damage to hepatocytes, atrophy of the thymus and spleen, and overall decrease in the spermatogenic activity of testes. An economical, simple, reliable, and quick method for the detection and quantification of T-2 toxin residues by HPTLC is also reported here. No residual T-2 toxin was detected in any of the organs tested, suggesting that T-2 toxin does not accumulate in tissues even at such a high exposure level.

Aphrodisiac and phytochemical studies of Cocculus hirsutus extracts in albino rats

To investigate the in vivo aphrodisiac activity of various extracts obtained from aerial parts Cocculus hirsutus ( C. hirsutus ). We evaluated whether oral administration of C. hirsutus has spermatogenic activity in male rats. Petroleum ether, chloroform and alcohol extract of aerial parts (stem and leaf) of C. hirsutus were administered at the dose level of 25 mg/100 g body weight to adult male albino rats for 30 days. The above said extracts have stimulated the spermatogenic activity and accessory reproductive organs performance in albino rats. Out of the three extracts administered, alcohol extract showed highly stimulant spermatogenic effects in mature male albino rats. Alcohol extract showed potent androgenic activity when treated in immature Albino rats. Males treated with the extract displayed more frequent and vigorous anogenital sniffing and mounting as compared to untreated animals. The increased spermatogenesis in extract treated groups was confirmed by change in histoarchitecture as evidenced by increase in number of spermatogonia, spermatocyte, spermatids and caudal spermatozoa. After subjecting to preliminary phytochemical screening, the alcohol extract showed positive tests for steroids, saponins, oils and fats, phenolic compounds and tannins. C. hirsutus exhibited remarkable increase in spermatogenic activity. These findings support the folk use of this plant as an aphrodisiac.

Investigation on the effect of aqueous Leaf extract of Acanthus montanus on spermatogenesis in Swiss mice

Acanthus montanus T. Anderson (Acanthaceae) possesses several medicinal properties; it is used in Cameroon as a folk medicine to treat pain, inflammation and threatened abortion. The aim of this study was to determine the effect of A. montanus aqueous extract on spermatogenesis in Swiss male albino mice and its mechanism of action.The extract, irrespective of dose, reversibly improved spermatogenic activity with 500mg/kg-1b.wt giving the most promising result. No significant reduction in body weight and weight of reproductive organs was observed and the gonadosomatic index remained stable irrespective of the increase in concentration of extract of A.momtanus. Increase in the spermatogenic indexes and total spermatogenic yield points to the potential of Acanthus montanus as a herbal –based remedy for spermatogenic dysfunction.

Effects of ischaemic post‐conditioning on the early and late testicular damage after experimental testis ischaemia–reperfusion

Ischaemic post-conditioning (IPostC) might represent an innovative surgical approach to protect organs from ischaemia and reperfusion (I/R) injury. We investigated the molecular mechanisms underlying the contrasting effects of IPostC on the early and late damage induced by testicular I/R injury. Testis I/R was induced by occluding the right testicular vessels using a clip. Male rats were divided into the following groups: sham, I/R and I/R+IPostC. In the I/R group, the clip was removed after 60min of ischaemia, and reperfusion was allowed for 30min, 1 and 30days. In the I/R+IPostC group, three cycles of 30-sec reperfusion and 30-sec ischaemia were performed after 60min of ischaemia and then reperfusion followed up for 30min, 1 and 30days. Following 30-min reperfusion, there was an increase in mitogen-activated protein kinases (MAPKs) in I/R rats; after 1day of reperfusion, interleukin-6, tumour necrosis factor-α and nuclear factor-κB (NF-κB) expression were significantly increased; IκB-α expression reduced; and a marked damage in both testes was observed. IPostC inhibited MAPKs, cytokines and NF-κB expression, augmented IκB-α expression and decreased histological damage in testes subjected to I/R. After 30days of reperfusion, I/R injury activated the apoptosis machinery, caused severe histological damage and reduced spermatogenic activity. By contrast, IPostC did not modify the apoptotic markers, the histological alterations as well as spermatogenic activity following 30days of reperfusion. Our data demonstrate that IPostC protects the testis from the early damage induced by I/R injury, but it does not protect against the late damage.

Temperature dependent action of growth hormone on somatic growth and testicular activities of the catfish, Clarias batrachus

Effects of growth hormone on somatic growth and testicular activities were studied during late quiescence and early recrudescence phases of the reproductive cycle of the catfish, Clarias batrachus. The administration of exogenous growth hormone (GH) during the late quiescence phase (December–January; ambient water temperature-15.2±1°C) did not influence the somatic growth as well as the testicular activity, as no change in body weight, testis weight, plasma level of insulin-like growth factor I (IGF-I) and testicular morphology was detected following GH treatment, though the plasma testosterone was marginally increased. While during the early recrudescence phase (March–April; ambient water temperature-28.1±2°C), GH treatment promoted the production of insulin like growth factor-I and testicular steroidogenic activity in a dose dependent manner, as was evident from the significant increase in the circulating levels of testosterone and estradiol-17β. GH treatment also increased body weight, testicular weight and gonadosomatic index, suggesting its involvement in testicular development. The GH treatment promoted spermatogonial proliferation and accelerated the spermatogenic process in the present catfish. These results, thus, suggest that GH influences the somatic growth and testicular activities depending on the temperature of the rearing water; warmer temperature and longer photoperiod promote testicular steroidogenic and spermatogenic activities in fish. This study has immense practical use in fisheries science.

Seasonal reproduction of yellowish myotis,Myotis levis(chiroptera: Vespertilionidae), from a Neotropical highland

With a nearly global distribution the vespertilionid bat Myotis represents one of the most exceptional examples of adaptive radiation among mammals. We investigated the reproductive activity of the vespertilionid bat yellowish myotis, Myotis levis, from a highland area in Southeastern Brazil. The data were obtained through histological analyses of the male and female genital systems from February 2010 to May 2011. The testes of the adult yellowish myotis showed seasonal morphological characteristics which were categorized in the following stages: rest, maturing, mature, and mating. Rest and maturing males were recorded throughout the rainy season (October-March). In the rest stage no spermatogenesis was observed and the epididymal duct was devoid of spermatozoa. Maturing individuals had started spermatogenesis and few spermatozoa were found in the epididymal duct. Mature males were found toward the end (February-March) of the rainy season, when full spermatogenic activity was recorded and spermatozoa were packed in the epididymal duct. Although not recorded, mating probably occurred in the middle of the dry season (April-September) when the cauda epididymis was enlarged and packed with sperm. The spermatozoa remained stored in the cauda epididymis for at least three months when the testes entered into regression. The ovaries showed all types of ovarian follicles throughout the study period except mature follicles which were registered only in July (mid-dry season). Lactating females were captured in the beginning of the rainy season. The seasonal reproductive characteristics of the yellowish myotis from this Neotropical highland area were similar those of epididymal sperm-storing temperate vespertilionids.

Two periods of total testicular regression are peculiar events of the annual reproductive cycle of the black Myotis bat, Myotis nigricans (Chiroptera: Vespertilionidae)

Myotis nigricans presents few and controversial reproductive data, which indicate geographical variation in reproduction. Thus, this study aimed to evaluate the seasonal modifications in testicular and epididymal morphologies in a tropical environment, submitting these organs to morphometric and immunohistochemical analysis. The observations revealed that this species presents two peaks of spermatogenic activity followed by two periods of total testicular regression (a quiescent pre-pubertal-like morphology, where only Sertoli cells and spermatogonia could be observed), in the same annual reproductive cycle, which seem to be only indirectly influenced by abiotic factors. This testicular behaviour seems to be synchronised with the caput and corpus epididymidis, but not with the cauda epididymidis, which presents aspects of sperm storage in May-June. The control of this variation seems to be directly linked to the expression of the androgen receptor, since, throughout the year, it is high in periods of testicular recrudescence and low in periods of deactivation. It is not thought to be directly linked to apoptosis, which is more pronounced in periods of recrudescence than in periods of regression.

Morphological Study of the Testis of Adult Sudanese Duck (Anas platyrhynchos)

The aim of the work to show the morphology of the testis of Adult Sudanese duck (Anas platyrhynchos). The adult duck testes were two bean-shaped‚ large and soft‚ the left testis was usually higher in position and larger in size than the right one. The testis was active during cold weather with the mean diameter of the seminiferous tubules being 124 µm in the duck. It was less active during the hot season with the mean diameter of the seminiferous tubules being 134 µm in the duck. The non-breeding season seemed to be characterized by a decline in the spermatogenic activity only and not by complete spermatogenesis. The mean volume of left testis in the adult duck was 9.12 cm'. They exceeded those of the right testes by 8%; the relative volume of the components remained essentially the same in both testes. The seminiferous tubules formed 90% of the volume of the testes in duck.

Histomorphometric evaluation of the Molossus molossus (Chiroptera, Molossidae) testis: The tubular compartment and indices of sperm production

Insectivorous bats play a very important role in the regulation of tropical ecosystems, but information about their reproductive cycle is lacking. Thus, male Molossus molossus were captured over the four seasons, and morphometric analyses of their testes were conducted to infer on the gonadal dynamics and the reproductive capacity of the species. Testes were immersed in Karnovsky fixative, and fragments were embedded in methacrylate and paraplast for morphometric and TUNEL assay respectively. The least gonadosomatic index (0.3%), tubulesomatic index (0.2%) and tubular diameter (133.2μm) occurred in summer. An adult M. molossus showed a total average of 48.9m of seminiferous tubules per gram of testis. Primary spermatocytes were observed in the zygotene at Stage 1 of the seminiferous epithelium cycle. The greatest meiotic index was obtained in winter (3.8 cells), and the general yield of spermatogenesis was higher in winter (64.5 cells) than in summer (19.1 cells). There was no difference in the apoptotic cells count among seasons. The Sertoli cell index was less in summer (5.9) than in fall (11.6), while the number of Sertoli cells per gram of testis did not vary significantly among the seasons (28.0×107). The spermatic reserve per gram of testis was greater in the fall (63.9×107) and winter (69.8×107) than summer (37.1×107). We conclude that M. molossus males show a continuous reproductive cycle, featuring greater spermatogenic activity during the fall and winter, a tubular length above the average of other mammals and a less support capacity of the Sertoli cells.

The Spermatogenic Effect of Yacon Extract and Its Constituents and Their Inhibition Effect of Testosterone Metabolism

We screened the pharmacological effects of a 50% ethanol extract of Yacon tubers and leaves on spermatogenesis in rats. As a result, we found that Yacon tuber extracts increased sperm number and serum testosterone level in rats. It has been reported that the crude extract of Yacon tubers and leaves contain phenolic acids, such as, chlorogenic acid, ferulic acid and caffeic acid by HPLC/MS analysis. We were interested in the contributions made by phenolic acid, particularly chlorogenic acid of Yacon tuber extract to the spermatogenic activity. After administering Yacon tuber extract or chlorogenic acid to rats for 5 weeks, numbers of sperm in epididymis were increased by 34% and 20%, respectively. We also administered ferulic acid, which has been reported to be a metabolite of chlorogenic acid and a constituent of Yacon tuber extract to investigate its spermatogenic activity in rats. Yacon tuber extract and ferulic acid increased sperm numbers by 43% and 37%, respectively. And, Yacon tuber extract, and chlorogenic acid showed significantly inhibition effect of testoeterone degradation in rat liver homogenate. We considered that the spermatogenic effect of Yacon tuber extract might be related to phenolic compounds and their inhibitory effect of testosterone degradation. Yacon showed the possibility as ameliorable agents of infertility by sperm deficiency and late onset hypogonadism syndrome with low level of testosterone.

Reproductive Biology of the Del Norte Salamander (Plethodon elongatus)

We examined seasonal reproductive patterns of the Del Norte Salamander, Plethodon elongatus, in mixed conifer and hardwood forests of northwestern California and southwestern Oregon. Seasonal size differences in reproductive structures suggested that maximum spermatogenic activity occurred during the late summer, with spermatozoa transfer to the vasa deferentia occurring in the fall through spring. Maximum development of mature follicles occurred during the winter; however, follicular growth occurred year-round and was asynchronous among individuals. Courtship and mating probably occurred in late fall through early spring, with egg deposition from spring into early summer. Reproduction for females was not annual, and patterns suggested that the reproductive cycle was biennial or less frequent. In contrast, evidence indicated annual reproduction in males. Gravid females contained an average of 10 mature follicles.

Crataegus monogyna fruit aqueous extract as a protective agent against doxorubicin-induced reproductive toxicity in male rats.

Doxorubicin (DOX) is a broad spectrum chemotherapeutic agent used in the treatment of several malignancies. The use of DOX in clinical chemotherapy has been restricted due to its diverse toxicities, including reproductive toxicity. Crataegus monogyna (C. monogyna) is one of the oldest medicinal plants that have been shown to be cytoprotective because of scavenging free radicals. The present study was undertaken to determine whether C. monogyna fruits aqueous extract could serve as a protective agent against reproductive toxicity during DOX treatment in a rat model through antioxidant-mediated mechanisms. Male Wistar rats were allocated to four groups. Two groups of rats were treated with DOX at a dose of 4 mg/kg intraperitoneally on days 1, 7, 14, 21, and 28 (accumulated dose of 20 mg/kg). One of the groups received C. monogyna fruits aqueous extract at a dose of 20 mg/kg per day orally for 28 days along with DOX. A vehicle-treated control group and a C. monogyna control group were also included. The DOX-treated group showed significant decreases in the body and organ weights and spermatogenic activities as well as many histological alterations. DOX treatment also caused a significant decrease in sperm count and motility with an increase in dead and abnormal sperms. Moreover, significant decrease in serum levels of testosterone and increased serum concentrations of FSH, LH, LDH, CPK, and SGOT were observed in DOX-treated rats. Notably, Crataegus co-administration caused a partial recovery in above-mentioned parameters. These findings indicated that doxorubicin can adversely damage the testicular tissue, while Crataegus co-administration could effectively prevent these adverse effects by effective inhibiting oxidative processes and restoration of antioxidant defense system.

Clinical Evaluation of the Spermatogenic Activity of the Root Extract of Ashwagandha (Withania somnifera) in Oligospermic Males: A Pilot Study

Ashwagandha (Withania somnifera) has been described in traditional Indian Ayurvedic medicine as an aphrodisiac that can be used to treat male sexual dysfunction and infertility. This pilot study was conducted to evaluate the spermatogenic activity of Ashwagandha root extract in oligospermic patients. Forty-six male patients with oligospermia (sperm count < 20 million/mL semen) were enrolled and randomized either to treatment (n = 21) with a full-spectrum root extract of Ashwagandha (675 mg/d in three doses for 90 days) or to placebo (n = 25) in the same protocol. Semen parameters and serum hormone levels were estimated at the end of 90-day treatment. There was a 167% increase in sperm count (9.59 ± 4.37 × 106/mL to 25.61 ± 8.6 × 106/mL; P < 0.0001), 53% increase in semen volume (1.74 ± 0.58 mL to 2.76 ± 0.60 mL; P < 0.0001), and 57% increase in sperm motility (18.62 ± 6.11% to 29.19 ± 6.31%; P < 0.0001) on day 90 from baseline. The improvement in these parameters was minimal in the placebo-treated group. Furthermore, a significantly greater improvement and regulation were observed in serum hormone levels with the Ashwagandha treatment as compared to the placebo. The present study adds to the evidence on the therapeutic value of Ashwagandha (Withania somnifera), as attributed in Ayurveda for the treatment of oligospermia leading to infertility.

Testicular testosterone: Estradiol ratio in domestic cats and its relationship to spermatogenesis and epididymal sperm morphology

The phenomenon of teratozoospermia in felids is not fully understood. In this study, we investigated the testicular androgen:estrogen balance in domestic cats and correlated these data with epididymal sperm morphology and the degree of spermatogenic activity. During spring and summer, testes and blood samples were obtained from 37 mixed-breed domestic cats (12 to 48 mo). The epididymal sperm were harvested and evaluated for sperm counts, motility, and morphology. Distal cytoplasmic droplets were not considered a defect, and samples were considered normozoospermic if they contained more than 60% normal sperm (N = 25) or teratozoospermic if they contained less than 45% normal sperm (N = 12). The testicular and serum concentrations of testosterone (T) and 17β-estradiol (E2) were determined with an enzyme immunoassay. The gonadosomatic index and epididymal sperm numbers and motility did not differ between groups. The percentage of normal sperm was higher in normozoospermic (74.3 ± 2.0, mean ± SEM) than in teratozoospermic samples (43.1 ± 1.4). The most prevalent sperm defects in the teratozoospermic group were abnormal acrosomes (9.7 ± 2.0) and bent midpieces (12.2 ± 2.0) or tails (24.0 ± 2.7) with cytoplasmic droplets. Histomorphometric data were similar between groups, although there was a lower Leydig cell nuclear volume in teratozoospermic samples. Normozoospermic samples contained a higher percentage of haploid cells and had a higher index of total spermatogenic transformation than teratozoospermic samples. Serum concentrations of T (0.5 ± 0.1 vs. 0.8 ± 0.4 ng/mL) and E2 (9.5 ± 1.2 vs. 11.4 ± 2.3 pg/mL) and testicular T concentrations (471.6 ± 65.3 vs. 313.4 ± 57.6 ng/g) were similar between groups. However, compared with normozoospermic samples, teratozoospermic samples had higher testicular E2 concentrations (8.5 ± 3.6 vs. 5.4 ± 0.5 ng/g) and a lower T:E2 ratio (31.8 ± 4.1 vs. 87.2 ± 11.6). There were significant correlations between testicular E2 values and percentages of normal sperm (r = −0.55) as well as those with primary sperm defects (r = 0.58) or abnormal acrosomes (r = 0.64). The T:E2 ratio was also correlated with meiotic index (r = 0.45) and percentage of normal sperm (r = 0.58). In conclusion, a high testicular E2 concentration and a reduced T:E2 ratio were significantly associated with higher ratios of abnormal sperm types, suggesting that the balance between androgens and estrogens is an important endocrine component in the genesis of teratozoospermia in felids.

Seasonal spermatogenic cycle and morphology of germ cells in the viviparous lizard Mabuya brachypoda (Squamata, Scincidae)

We describe seasonal variations of the histology of the seminiferous tubules and efferent ducts of the tropical, viviparous skink, Mabuya brachypoda, throughout the year. The specimens were collected monthly, in Nacajuca, Tabasco state, Mexico. The results revealed strong annual variations in testicular volume, stages of the germ cells, and diameter and height of the epithelia of seminiferous tubules and efferent ducts. Recrudescence was detected from November to December, when initial mitotic activity of spermatogonia in the seminiferous tubules were observed, coinciding with the decrease of temperature, photoperiod and rainy season. From January to February, early spermatogenesis continued and early primary and secondary spermatocytes were developing within the seminiferous epithelium. From March through April, numerous spermatids in metamorphosis were observed. Spermiogenesis was completed from May through July, which coincided with an increase in temperature, photoperiod, and rainfall. Regression occurred from August through September when testicular volume and spermatogenic activity decreased. During this time, the seminiferous epithelium decreased in thickness, and germ cell recruitment ceased, only Sertoli cells and spermatogonia were present in the epithelium. Throughout testicular regression spermatocytes and spermatids disappeared and the presence of cellular debris, and scattered spermatozoa were observed in the lumen. The regressed testes presented the total suspension of spermatogenesis. During October, the seminiferous tubules contained only spermatogonia and Sertoli cells, and the size of the lumen was reduced, giving the appearance that it was occluded. In concert with testis development, the efferent ducts were packed with spermatozoa from May through August. The epididymis was devoid of spermatozoa by September. M. brachypoda exhibited a prenuptial pattern, in which spermatogenesis preceded the mating season. The seasonal cycle variations of spermatogenesis in M. brachypoda are the result of a single extended spermiation event, which is characteristic of reptilian species.