Morphology Of Seminiferous Tubules Research Articles

Testicular degeneration in Huntington disease

Huntington disease (HD) is an adult onset, neurodegenerative disorder that results from CAG expansion in the HD gene. Recent work has demonstrated testicular degeneration in mouse models of HD and alterations in the hypothalamic-pituitary-gonadal (HPG) axis in HD patients. Here, we show that HD patients have specific testicular pathology with reduced numbers of germ cells and abnormal seminiferous tubule morphology. In the YAC128 mouse model, testicular degeneration develops prior to 12 months of age, but at 12 months, there is no evidence for decreased testosterone levels or loss of GnRH neurons in the hypothalamus. This suggests that testicular pathology results from a direct toxic effect of mutant huntingtin in the testis and is supported by the fact that huntingtin is highly expressed in the affected cell populations in the testis. Understanding the pathogenesis of HD in the testis may reveal common critical pathways which lead to degeneration in both the brain and testis.

The protective role of erdosteine on testicular tissue after testicular torsion and detorsion

Testicular torsion and detorsion are important clinical problems for infertile man and oxidative stress may have a role in this clinical situation. The aim of this study was to investigate the protective role of erdosteine, an antioxidant, on unilateral testicular reperfusion injury in rats. The rats were divided into four groups including seven rats in each group: control, torsion, torsion/detorsion and torsion/detorsion+erdosteine. Rats, except the sham operation group, were subjected to left unilateral torsion (720( composite function) rotation in the clockwise direction) without including the epididymis. The experiments were finished after sham operation time for control, 120 min torsion for torsion group and 120 min torsion and 240 min detorsion for torsion/detorsion groups. Bilateral orchiectomy was performed for all groups of rats. The ipsilateral and controlateral testis were divided into two pieces to analyse biochemical parameters and to investigate the light microscopic view. Malondialdehyde level of ipsilateral testis was increased in torsion and torsion/detorsion groups in comparison with the other groups (p < 0.05). Erdosteine treatment ameliorated lipid peroxidation after torsion/detorsion in ipsilateral testis (p < 0.05). Also, xanthine oxidase activity of ipsilateral testis was increased in torsion/detorsion group in comparison with the others (p < 0.05). Nitric oxide (NO) level of ipsilateral testis was higher in all experimental groups than sham operated control group (p < 0.05). Also, NO level of torsion group was increased in comparison with detorsion groups (p < 0.05). Erdosteine treatment caused increased glutathione peroxidase activity in comparison with torsion and torsion/detorsion groups and catalase activity in comparison with the other groups in ipsilateral testis (p < 0.05). Superoxide dismutase activity of ipsilateral testis was higher in torsion/detorsion and torsion/detorsion+erdosteine groups than control and torsion groups (p < 0.05). The biochemical parameters were not affected in controlateral testis in all groups. Torsion, torsion/detorsion and torsion/detorsion+erdosteine groups showed ipsilateral testicular damage in the histological examination, but the specimens from torsion/detorsion had a significantly greater histological injury than those from the other groups (p < 0.05). Control rats showed normal seminiferous tubule morphology. Rats in torsion group had slight-to-moderate disruption of the seminiferous epithelium. Rats in torsion/detorsion group displayed moderate-to-severe disruption of the seminiferous epithelium. In all animals from torsion/detorsion+erdosteine group, the testicular tissues were affected with slight-to-moderate degenerative changes of the seminiferous epithelium. Administration of erdosteine resulted in a significantly reduced histological damage associated with torsion of the spermatic cord compared with torsion/detorsion. In all groups, the contralateral testes were histologically normal. In conclusion, the results clearly displayed that erdosteine treatment may have a protective role on testicular torsion/detorsion injury.

Overview of male reproductive pathology.

An understanding of form and function is important for examination of the male reproductive tract. A basic understanding of spermatogenesis and hormonal function in the reproductive tract is essential for the pathologists in this evaluation. Gross and histologic reproductive changes need to be distinguished from normal variation and correlated with the reproductive status of the animal. This is especially important when correlating histologic changes with organ weight and other reproductive parameters, such as seminal analysis data. Sexual maturity of animals and tissue handing can impact interpretation. Sexual immaturity of preclinical safety animals can present challenges for accurate identification of compound-related changes. Likewise, proper handling of unfixed reproductive tissues and appropriate selection of a fixation protocol are important in avoiding artifacts that may interfere with the microscopic evaluation. The histopathology technician needs to recognize testicular landmarks that allow for correct orientation at trimming so the pathologist can assess not only the morphology of seminiferous tubules but also the outflow tract. For the most effective evaluation of the male reproductive tract, the testes and epididymides should be examined concurrently. Although the term "staging" is often used inappropriately, the pathologist should review testicular tissues in a "stage-aware" manner. This article reviews gross and histologic changes of the male reproductive tract as well as tissue orientation and fixation to assist in accurate interpretation of potential treatment-related changes in male reproduction.

Effect of testosterone and cortisol administration on the reproductive tract of male Antechinus stuartii (Marsupialia).

The life history of Antechinus stuartii, a marsupial, is highly synchronized and culminates in a brief mating period that is followed by complete male mortality. The accessory reproductive tracts of male A. stuartii enlarge in association with testosterone and cortisol hormone concentrations, but this appears to be unrelated to the spermatogenic cycle. The present study examined the effects of testosterone and cortisol on the male reproductive tract. Four groups of adult males from May (when plasma testosterone and cortisol concentrations are low) were given depot injections of testosterone esters or synthetic cortisol in doses that mimic concentrations found in males in the breeding period (August). Males were given either saline, testosterone only, cortisol only, or testosterone plus cortisol. Experimental groups did not differ in the seminiferous tubule morphology. However, the cells from the caudal end of the epididymides of both testosterone groups were considerably hypertrophied compared with males treated with saline or cortisol only. Testosterone treatment significantly increased prostate and bulbourethral gland mass, although addition of cortisol to the testosterone administration diminished this effect. The morphology of the accessory reproductive tract of males treated with either saline or cortisol only was similar to that of untreated males at the same time of year, and the morphology of the accessory reproductive tract of males treated with testosterone plus cortisol was similar to that of untreated males in the breeding season. Like some other marsupials, the spermatogenic cycle in A. stuartii is apparently not correlated with androgen activity, while the accessory reproductive tract is affected by androgens.

Effect of seminiferous tubule size on hCG-induced regeneration of peritubular Leydig cells in hypophysectomized, EDS-treated rats.

Following their selective destruction 3 weeks previously by administration of ethane dimethanesulphonate (EDS) the regenerative capacity of Leydig cells was assessed in relation to seminiferous tubule morphology in hypophysectomized adult rats administered 7 daily injections of 100 iu hCG. Total Leydig cell volume per testis in hCG-treated rats (30.2 +/- 3.2 microliters, mean +/- SEM) was significantly (p < 0.01) greater than in the testes of rats at 3 and 4 weeks after EDS-treatment (7.6 +/- 0.7 and 22.7 +/- 1.4 microliters, respectively). Regeneration of Leydig cells in hCG-treated rats significantly (p < 0.05) favoured peritubular locations (18.6 +/- 2.8 microliters/testis) compared to central or perivascular sites of origin (11.6 +/- 1.2 microliters/testis). Partial restoration of spermatogenesis occurred in hCG-treated rats (tubule diameters usually > 250 microns) and a significant inverse correlation was found between peritubular Leydig cell percentage, or total volume per testis, and the volumetric proportion of seminiferous tubules (r = -0.94, p < 0.001) or the seminiferous epithelium (r = -0.73 to -0.79, p < 0.05-0.01). No significant (p > 0.4-0.9) correlation existed between centrally-regenerated Leydig cells and these parameters. The results show that in response to hCG stimulation, Leydig cells are more likely to develop around smaller seminiferous tubules, suggesting that hCG alone cannot mimic the expected pattern of Leydig cell regeneration (central and peritubular origins) which occurs during normal sexual maturation or at 3-4 weeks after EDS treatment. It is concluded that other factors, possibly FSH, are required for typical Leydig cell development which in turn may be influenced by local cellular growth factors originating from either the seminiferous tubules or the adjacent intertubular tissue.

Liposome-mediated macrophage depletion: an experimental approach to study the role of testicular macrophages in the rat.

Liposome-entrapped dichloromethylene diphosphonate was injected locally into the right testes of adult rats. This treatment, which has been found to deplete resident macrophages in some other organs, reduced the number of testicular macrophages by at least 90%. Testicular weight and seminiferous tubule morphology were unaffected by liposome treatment. Leydig cell testosterone secretion gradually declined in the macrophage-depleted testes, and there was a compensatory increase in Leydig cell size and testosterone secretion in the contralateral saline-injected testes. These observations suggest that macrophages influence Leydig cell function locally. It is concluded that liposome-mediated depletion of testicular macrophages may serve as an experimental model with which to study the physiological role of these cells.

2,5-Hexanedione exposure alters the rat sertoli cell cytoskeleton: I. Microtubules and seminiferous tubule fluid secretion

2,5-Hexanedione (2,5-HD) is a testicular and nervous system toxicant with an unknown mechanism of action. In this study, the effects of 2,5-HD on seminiferous tubule fluid (STF) secretion, testis morphology, and tubulin distribution were examined. Charles River CD rats (200 g) were exposed to 1% 2,5-HD in the drinking water for 5 weeks followed by a 3-week recovery period. STF secretion was measured by efferent duct ligation, and testis cross sections were prepared at 2, 3, 3.43, 3.57, 3.86, 4, and 8 weeks after beginning exposure. A dramatic inhibition of STF secretion was observed between Weeks 3 and 4. The inhibition of STF secretion occurred following simultaneous changes in Sertoli cell and elongate spermatid morphology but prior to changes in round spermatid morphology. Also, alterations in seminiferous tubule tubulin distribution were observed with kinetics similar to those for changes in seminiferous tubule morphology. This temporal sequence suggests a model of 2,5-HD-induced injury in which populations of germ cells are differentially sensitive to impairment of Sertoli cell function.

Evaluation of the effect of selective germ cell depletion on subsequent spermatogenesis and fertility in the rat.

Rats were treated with a single high dose of methoxy acetic acid (MAA; 650 mg/kg) specifically to deplete seminiferous tubules of pachytene and later spermatocytes. The impact of this selective depletion on subsequent spermatogenesis, sperm output and fertility was then evaluated at intervals ranging from 3 days to 10 weeks. Cauda epididymal sperm number was reduced progressively beyond 2 weeks post-treatment and reached a nadir at 5-6 weeks (28-34% of control values) before recovering progressively back to control levels at 10 weeks. Sperm motility was reduced significantly at 4-7 weeks post-treatment with a nadir at 6 weeks (35% of control values). Thus, at 5-6 weeks after MAA treatment, motile sperm output was reduced by 82-88%. Despite these changes, there was little evidence for infertility in the majority of treated males during a serial mating trial. Evaluation of seminiferous tubule morphology combined with germ cell counts at stage VII of the spermatogenic cycle confirmed that, initially, MAA induced the specific loss of pachytene and later spermatocytes at all stages other than early to mid stage VII. Maturation depletion of germ cells at later intervals was consistent with the initial effects of MAA, although at 21 days post-treatment a number of unpredicted (? secondary) changes in spermatogenesis were observed. These were (a) a reduction in number of pachytene spermatocytes at late stage VII/early stage VIII, (b) retention of sperm at stages IX-XIV, and (c) increased degeneration of pachytene spermatocytes and round spermatids at stage VII and of secondary spermatocytes at stages XIV-I. Whilst none of these changes was severe, together they probably accounted for the unexpectedly prolonged drop in sperm output. It is concluded that whilst deleterious changes in spermatogenesis may occur secondarily following MAA treatment, for the most part spermatogenesis proceeds normally and fertility is largely maintained despite a massive but transient decrease in sperm output.

The effect of acute treatment with two goitrogens on plasma thyroid hormones, testosterone and testicular morphology in adult male rats

1. 1. Hypothyroidism was induced in adult male rats by treatment with either iopanoic acid (IOP) or propylthiouracil (PTU). The hypothyroid animals were maintained for a period of 4 weeks. 2. 2. The IOP and PTU treatments produced drastically different thyroid hormone profiles during the treatment period. 3. 3. Serum testosterone levels were not significantly different from controls in either of the goitrogen-treated groups. 4. 4. Testes weights and germ cell populations were not significantly different from controls in either of goitrogen treated groups. 5. 5. Seminiferous tubule morphology showed no significant variation in lumen size or basal lamina structure in either of the treatment groups when compared to the controls.

Interactions of sertoli cells with myoid cells in vitro.

Preparations of Sertoli cells and peritubular myoid cells from testes of 20-day-old rats were cultured alone or together, and cellular interactions were assessed. In the co-cultured system, Sertoli cells within plaques became elevated, forming macroscopically visible mounds and protrusions. The morphologic characteristics of these structures were determined with scanning and transmission electron microscopy. The formation of a limiting membrane observed between individual Sertoli cell nodules and surrounding myoid cells resembled some aspects of the morphology of seminiferous tubules. Long-term co-cultures of Sertoli cells and myoid cells, stimulated by follicle stimulating hormone (FSI-l), continued to secrete androgen binding protein (ABP) under conditions in which Sertoli cell monocultures ceased production of ABP. The specificity of these cellular interactions was investigated. Bladder smooth muscle cells could substitute for peritubular myoid cells in eliciting mound formation of co-cultured Sertoli cells, but embryonic fibroblasts could not. However, embryonic fibroblasts, which did not secrete ABP, permitted FSIl-stimulated Sertoli cells in long-term co-culture to maintain ABP production. In contrast, fibroblasts from the tunica albuginea, when co-cultured with Sertoli cells, neither elicited mound formation nor supported ABP production. We conclude that while unique specificity of cellular interactions between Sertoli cells and peritubular myoid cells is not apparent in cultured preparations from testes of 20-day-old rats, these cells do retain some of the properties required for aggregation and tubule formation characteristic of tubule morphogenesis.

Chronic Effects of [D-Trp6,Pro9-NEt]Luteinizing Hormone-Releasing Factor on Reproductive Processes in the Male Rat*

Chronic administration of a potent LRF agonist, [D-Trp6,Pro9-NEt]LFR (A), to intact adult male rats induced a dose-related decrease in testicular and accessory organ weights, diminished production of testosterone (T), and disrupted tubular morphology, indicative of suppression of spermatogenesis. Transient elevations of plasma progesterone levels and a marked reduction of PRL secretion were also observed in A-treated rats. The effects of A on testicular weights, T levels, and seminiferous tubule morphology were already apparent 3 days after the first injection. Administration of A was equally effective when administered daily or at 1- to 4-day intervals in lowering steroid levels and testicular weights. After a 1-week daily exposure to A, seminal vesicles and prostate weights as well as T levels returned to control values within 1--2 weeks. Testicular weights, however, were still depressed 4 weeks after cessation of treatment, and germinal epithelium was disrupted in 30--40% of the tubules. Measurement of T and LH plasma levels after each daily injection of A indicated a blunting of succeeding A-induced elevations of LH and T, which lasted up to 72 h after a single administration of A. The observation that cultured pituitary cells repeatedly exposed to A showed a similar blunting of LRF-induced LH elevation suggests that the decrease in pituitary responsiveness was not exclusively due to steroid feedback. Administration of T propionate to A-treated intact rats was unable to restore normal testicular weights and seminiferous tubule morphology, whereas in hypophysectomized rats, T propionate maintained qualitatively normal spermatogenesis even in the presence of A. These results coupled with the observation that high levels of hCG and PMS gonadotropin had effects similar to those of A on the tubular morphology of intact rats suggest the importance of pituitary secretion in mediating the deleterious effects of A on reproductive functions in the male rat.

Chronic Effects of [D-Trp6-Pro9-NEt]Luteinizing Hormone-Releasing Factor on Reproductive Processes in the Female Rat*

LRF and one of its highly potent analogs, [D-Trp6-Pro9-NEt]LRF (A), were tested for their effects on pregnancy. Daily doses of A prevented implantation and/or caused resorption of implanted blastocysts in mated female rats. This effect was dose related and was most evident when given in regimens including days 5-7 or days 9-10 or pregnancy. LRF also has antigonadal effects, but at much higher doses than A. The use of corn oil vs. 0.1% gelatin-saline improved the effectiveness of low doses of A. Termination of pregnancy in A- or LRF-treated rats is most probably due to the markedly diminished progesterone secretion, which could result from the secretion of biologically inactive gonadotropins, reduced pituitary responsiveness to endogenous LRF, or down-regulation of gonadal receptors for LH.

Testicular ultrastructure and fertility in the restricted color (H-re) rat.

Breeding experiments demonstrated that the average age at onset of fertility of male H” (restricted color) rats was 71 ± 9 (SD) days, while normal color (N) males were fertile by 65 ± 6 (SD) days of age. Two of the ten H” males studied were never fertile. Length of continuous fertility in H” males was highly variable (range = 0-122 days) and averaged 48 ± 49 (SD) days. Ultrastructural studies were undertaken to investigate structural manifestations of this genetic infertility. A prominent feature of the maturing (35-60 days of age) H’ testis was the presence of vacuoles within the cytoplasm of Sertoli cells. Inclusions were often observed within the nuclei of spermatids. The cytoplasm of these cells contained numerous vacuoles and malformed flagella. The morphology of seminiferous tubules from mature (over 60 days of age) H” rat testis was variable. Some tubules displayed only the alterations observed in the maturing testis. Others were characterized by atrophic Sertoli cells and reduced numbers of germ cells. The presence of abnormal sperm heads and ilagellar elements in Sertoli cell cytoplasm suggested that degenerating germ cells had been phagocytosed by those Sertoli cells. Nuclei of Sertoli cells often contained membrane-bounded inclusions, and, in older animals, numerous small lipid droplets and vacuoles of varying sizes were distributed in the cytoplasm. Degenerating Sertoli cells were observed occasionally near the lumen of the tubule. Although there was an apparent increase in the incidence of Leydig cells, their absolute numbers were likely unchanged from normal controls. Leydig cell fine structure was similar to that observed in control rats. The possibility of a defective response of the seminiferous tubules to FSH is discussed in the light of the observed structural alterations in the H” rat.

Mutagenicity of DDT in mice, Drosophila melanogaster and Neurospora crassa.

The pesticide DDT was examined for possible mutagenicity in mice, D. melanogaster and N. crassa. Through the use of the dominant-lethal assay it was found that acute oral doses of DDT (2 x 150 mg/kg body weight) in male mice induced dominant lethal mutations in early spermatid and spermato-cyte stages. Chronic oral doses of DDT (2 x 100 mg/kg body weight per week for 10 weeks) in male mice caused a persistent increase in the number of dominant lethal mutations. Histological sections showed that chronic treatment of mice with DDT caused changes in seminiferous tubule morphology and degeneration of B-type spermatogonia. Acute treatment of mice with DDT caused an increase in spermatocyte chromosome breakage, stickiness and precocious separation of the X and Y bivalent.

Effects of Rapid Massive Doses of Gamma-Rays on the Testes and Germ Cells of the Rat

Effects of ionizing radiations on the testes were reported by Albers-Shonberg (1) as early as 1903. Since that time, effects of both chronic and acute total-body -and X-ray exposures on the testes of laboratory animals have been studied extensively. In addition, two rather complete studies of the course of testicular injury in the human being after ionizing radiation exposures were reported by Oakes and Lushbaugh (2) and by Robinson and Engle (3). Literature on this subject is voluminous, but there are still areas of disagreement, particularly on the question of the effect of irradiation on spermatogonia. Eschenbrenner (4) feels that the effect of irradiation on spermatogonia is one of mitotic arrest, whereas Russell (5) and Oakberg (6) state that spermatogonia are killed by irradiation; Oakberg further suggests that death of the spermatogonia is a result of X-ray damage at the chromosome level. Reviews of this subject have been covered in previous articles (6, 7) and excellent studies on normal morphology of seminiferous tubules and spermatogenesis in the rat have been documented by Curtis (8) and Roosen-Runge and Giesel (9). Further review at this time is not justified. The studies presented here are unique in that the magnitude of the intensity and the total doses of y-radiation employed were much higher than in previous studies. Exposures to massive rapid doses of y-rays were made in hopes that they would enhance the effects and lead to a better understanding of radiation-produced azoospermia.