Endocrine profile and testicular histomorphometry at puberty in rat offspring from diabetic mothers

This investigation was conducted to evaluate the effects of maternal diabetes on foetal testicular structure and function and reproductive hormone levels. Sixteen adult female rats were divided in two groups. Diabetes was induced in one group by alloxan. Both groups became pregnant by natural mating. Blood was collected from 60-day-old male offspring from both groups and the level of testosterone, FSH and LH measured in their serum. At the same time, the weight and volume of testes and various histological parameters from testicular histological sections were determined. Results showed significant decrease in LH, FSH and testosterone in sera of offspring from diabetic mothers (ODM) compared with the control group. Body weight and weight and volume of testes from ODM were about 25.5%, 51.6% and 50.8% higher respectively than those of the control group (P < 0.05). Number of seminiferous tubules increased (+15%) significantly (P < 0.05), whilst thickness of testicular capsule (−16%), number of Leydig cells (−14%), number of Sertoli cells (−10%), number of spermatogonia (−38%) and diameter of seminiferous tubules (−17%) showed significantly reduced values in the ODM compared to controls (P < 0.05). In conclusion, maternal hyperglycaemia has deleterious effects on testicular parameters during foetal life which will affect reproductive endocrinology during puberty and may impact on fertility.     

Testicular Biopsy Score Count After Vasectomy in Albino Rats

Context: One of the challenging problems faced by the entire world is population explosion. The vasectomy is simple, safe, quick and effective vital method of male sterilization. In the recent years a large number of vasectomies have been performed in India, since the inception of National Family Planning Program in 1956. Thus the number of request for the restoration of fertility is also increased. Aim: The present study was carried out to know whether the testicular biopsy score count, indicating the process of spermatogenesis remains normal after vasectomy. Material & Methods: The testicular biopsy count of testes of 50 male albino rats was studied one, two, three and four months after vasectomy, in 10 male albino rats of each case and 10 male albino rats served as control. Result: After vasectomy seminiferous tubules are cut in various planes covered externally by connective tissue stroma with normal microscopic picture. The spermatogonia, spermatocytes, spermatids, Sertoli cells and spermatozoa show normal structure with normal size blood vessels in interstitial connective tissue, in vasectomised and control rats. In some seminiferous tubules granular cytoplasmic vesicle like structures are seen filling the lumen and spermatids in metamorphosis phase to spermatozoa. Many round or elongated heads of spermatozoa are present at apical portion of Sertoli cells. The control rats as well as vasectomised rats at four after vasectomy have shown the testicular biopsy score count of nine (9) and ten (10) on TBSC of Johenson. Conclusion: On critical analysis it is concluded that the testicular biopsy score count remains normal at four months after vasectomy.     

Endocrine profile and testicular histomorphometry in adult rat offspring of diabetic mothers

This investigation was conducted to evaluate the effect of maternal diabetes on fetal testicular structure and function, and reproductive hormones levels. Sixteen female rats were divided into two groups. Diabetes was induced in one group by alloxan. Blood was collected from 90-day-old male offspring of both groups, and the level of blood glucose, testosterone, FSH and LH in their serum was measured. Weight, volume and various histological parameters of testes were determined. A significant increase in blood glucose and decrease in LH, FSH and testosterone in sera of offspring of diabetic mothers (ODM) were observed. The weight and volume of testes in the ODM were 22.7 and 22.9% higher, respectively, than those of the control group (P < 0.05), while the ratio of testes to body weight did not change significantly. The number of seminiferous tubules increased (+21%) significantly (P < 0.05), while thickness of the testicular capsule (−25%), number of Leydig cells (−15.6%), number of Sertoli cells (−14.9%), number of spermatogonia (−26.3%) and diameter of seminiferous tubules (−11%) showed significantly reduced values in the ODM compare to the control. In conclusion, maternal hyperglycemia has a deleterious effect on testicular parameters during fetal life, which will affect reproductive endocrine during postpuberty.     

The influence of vasovasostomy on testicular alterations after vasectomy in Lewis rats

The occurrence of alterations in testicular weight and morphology after vasectomy and vasectomy reversal by vasovasostomy was studied in Lewis rats. Animals were studied 3, 4, and 7 months after bilateral vasectomy or a vasectomy followed 3 months later by vasovasostomy. Other rats served as sham-operated controls. The weights of the testes in vasectomy and vasovasostomy animals fell into two groups-small testes weighing less than 0.88 g and normal-sized testes of 1.2 g or more. When the extent of testicular alterations was estimated in sections for light microscopy by use of a semiquantitative testicular biopsy score count (TBSC), the morphology of the testes corresponded closely to the testis weight (r = .94), small testes having correspondingly low TBSC scores. In severely altered small testes, the seminiferous tubules were narrower than in sham-operated rats, and numbers of germ cells were greatly depleted. Many tubules contained only Sertoli cells and spermatogonia, although spermatocytes were present in a minority of tubules. A few seminiferous tubules contained multinucleate spermatids. Electron microscopy of severely altered tubules revealed closely apposed processes of Sertoli cells, which contained filaments, microtubules, and endoplasmic reticulum. In contrast, testes with normal weight in vasectomy and vasovasostomy groups resembled those of the sham-operated animals. Comparison of distributions of testicular biopsy score counts demonstrated differences between vasectomy and vasovasostomy groups as time after operation increased. At the 3-4-month intervals, approximately one-third of the testes were severely altered in both vasectomy and vasovasostomy groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Testicular dysfunction induced by penconazole fungicide on male albino rats

In the present study, penconazole fungicide was examined for its affect on the morphology and function of testes in rats. Male rats were orally administered penconazole at a dose of 50 or 100 mg/kg, three times/week, for 9 months. Testosterone hormone level was measured using enzyme-linked immunosorbent assay (ELISA). Testicles were submitted for histopathological examination using light microscope. Testicles were exposed for more investigation using transmission electron microscope. Quantitative analysis of seminiferous epithelial cycle and Leydig cells were obtained. The results revealed that a significant decrease in testosterone hormone level than the control group. Light microscope examination showed necrotic and degenerative changes in testes at the level of seminiferous tubules. Sertoli, Leydig, and germ cell numbers showed significant depletion. Ultrastructural investigation showed Sertoli and Leydig cells had several morphological alterations. Spermatogonic cells showed multiple features of apoptosis. From the previous findings, we concluded that penconazole fungicide induced structural and functional testicular impairment. The use of penconazole as a fungicide must be restricted and regularly monitored in the environment.     

Efferent duct toxicity with secondary testicular changes in rats following administration of a novel leukotriene A₄ hydrolase inhibitor

The efferent ducts represent an important site of toxicity in the male reproductive tract but are not routinely examined in toxicity studies. This article describes a primary efferent duct toxicity that resulted in secondary testicular changes in rats. Male rats were administered LTI-1, a leukotriene A? hydrolase inhibitor, at doses up to 250 mg/kg/d for 3 month or 150 mg/kg/d for 6 month. At the highest dose levels, testicular changes were predominantly unilateral and characterized by diffuse dilation or atrophy of the seminiferous tubules. These testicular changes correlated with granulomatous inflammation in the corresponding efferent ducts, suggesting that the mechanism for the testicular changes involves obstruction and impaired fluid reabsorption in the efferent ducts. Subsequent buildup in fluid volume and back-pressure upstream of the blockage cause dilation of the seminiferous tubules, which, in its late stages, progress to tubular atrophy. There are important differences in efferent duct anatomy between rats and larger mammals, including humans, such that the latter are less susceptible to testicular injury by this mechanism. Because of the limited relevance of this rat-specific finding to humans, it is important to distinguish testicular changes secondary to efferent duct toxicity from primary drug-induced testicular toxicity.     

Antireproductive effect of the calcium channel blocker amlodipine in male rats.

The purpose of the present study was to investigate whether treatment of male rats with the calcium antagonist amlodipine, used in the treatment of hypertension and angina, interferes with the reproductive function of male rats. Amlodipine treatment (0.04 mg amlodipine besylate/rat/day for 30 days) decreased plasma follicle-stimulating hormone and testosterone but not luteinizing hormone or prolactin concentrations (measured by double-antibody radioimmuno-assay). A significant reduction (23%) was observed in sperm density (sperm suspension collected from the cauda epididymidis) as well as in the amount of mature spermatids (14%) and Sertoli cells (9%) counted in seminiferous tubule cross-sections (400 x magnification). The results reveal the deleterious effects of subacute amlodipine treatment on the reproductive function of male rats.     

Association between testicular dysgenesis syndrome (TDS) and testicular neoplasia: evidence from 20 adult patients with signs of maldevelopment of the testis

Based on a well established association between testicular cancer and undescended testis and more recent publications on epidemiological links between these disorders and male infertility, we proposed the existence of a testicular dysgenesis syndrome (TDS). In most cases TDS presents with impaired spermatogenesis, only in rare cases the full range of its signs, including genital malformations and testicular cancer can be seen in one patient. In order to further corroborate our hypothesis about the presence of testicular dysgenesis in patients with testicular abnormalities, we decided to re-analyse recent testicular biopsies derived from patients with infertility, hypospadias and undescended testis. We searched for histological signs of testicular dysgenesis: microliths, Sertoli-cell-only tubules, immature seminiferous tubules with undifferentiated Sertoli cells, and tubules containing carcinoma in situ (CIS) cells. We identified 20 patients who fulfilled the histological criteria for testicular dysgenesis, 9 of whom were diagnosed with uni- or bilateral testicular germ cell neoplasia, and the remaining ones with subfertility. The presence of CIS was detected in 5 patients (3 of them with overt contralateral germ cell tumours). In all but one of the CIS cases, at least one additional sign of testicular dysgenesis was detected. Clinical records of all patients were subsequently analysed. The majority of cases had oligozoospermia or azoospermia. Their reproductive hormone profiles correlated with the results of semen sampling and testicular histology. In conclusion, our study of 20 patients with various reproductive abnormalities provided evidence that TDS is a real clinical entity. We speculate that most of these abnormalities are caused by adverse environmental effects rather than specific gene mutations.     

COMMENTS

Based on a well established association between testicular cancer and undescended testis and more recent publications on epidemiological links between these disorders and male infertility, we proposed the existence of a testicular dysgenesis syndrome (TDS). In most cases TDS presents with impaired spermatogenesis, only in rare cases the full range of its signs, including genital malformations and testicular cancer can be seen in one patient. In order to further corroborate our hypothesis about the presence of testicular dysgenesis in patients with testicular abnormalities, we decided to re-analyse recent testicular biopsies derived from patients with infertility, hypospadias and undescended testis. We searched for histological signs of testicular dysgenesis: microliths, Sertoli-cell-only tubules, immature seminiferous tubules with undifferentiated Sertoli cells, and tubules containing carcinoma in situ (CIS) cells. We identified 20 patients who fulfilled the histological criteria for testicular dysgenesis, 9 of whom were diagnosed with uni- or bilateral testicular germ cell neoplasia, and the remaining ones with subfertility. The presence of CIS was detected in 5 patients (3 of them with overt contralateral germ cell tumours). In all but one of the CIS cases, at least one additional sign of testicular dysgenesis was detected. Clinical records of all patients were subsequently analysed. The majority of cases had oligozoospermia or azoospermia. Their reproductive hormone profiles correlated with the results of semen sampling and testicular histology. In conclusion, our study of 20 patients with various reproductive abnormalities provided evidence that TDS is a real clinical entity. We speculate that most of these abnormalities are caused by adverse environmental effects rather than specific gene mutations.     

Macro-orchidism: light and electron microscopic study of four cases.

A hormonal and quantitative light microscopy study of one man with macro-orchidism associated with mental retardation and fragile X chromosome (case no. 1) and three men with idiopathic macro-orchidism (cases no. 2 to 4) is reported. Hormonal study revealed slightly increased follicle-stimulating hormone serum levels in cases no. 1 to 3. The testes from cases no. 1 (orchidoepididymoectomy specimen) and 2 (testicular biopsy) presented interstitial edema and three different tubular patterns that were arranged in a mosaic-like manner. Type I tubules had an increased diameter (less than 220 microns), dilated lumen, and thin seminiferous epithelium usually consisting of Sertoli cells, spermatogonia, primary spermatocytes, and sometimes a few spermatids. Type II tubules had a normal diameter (180 to 220 microns) and germ cell development varied between complete spermatogenesis and Sertoli-cell-only tubules. Type III tubules had decreased diameter (less than 180 microns), atrophic seminiferous epithelium, and thickened tunica propria. The appearance of the nuclei of the Sertoli cells in the three types of tubules could be either mature or immature. Some of the mature Sertoli cells presented a granular cytoplasm. A few of these granular cells grouped together, forming nests that protruded into the tubular lumen. The testicular biopsies from cases no. 3 and 4 only presented type II tubules that contained both mature and immature Sertoli cells. Quantitative study revealed that the large testicular size was principally due to an increased tubular length in all four cases. Although the seminiferous tubule lesions and interstitial edema suggest an obstructive process, the testicular excretory ducts (studied in case no. 1) appeared normal or only slightly dilated. It is possible that the seminiferous tubule lesions (dilated lumen and germ cell depletion) might be secondary to the Sertoli cell lesions (granular cytoplasm and nuclear immature-like pattern.     

An autopsy case of primary mixed choriocarcinoma and mature teratoma located in the thymic region associated with elevated human chorionic gonadotropin levels and characteristic testicular changes

An autopsy case of a 19-year-old male Japanese student with a primary mixed choriocarcinoma and mature teratoma in the thymic region is reported. The patient died 7 days after he first noticed fever and dyspnea. On autopsy, an anterior mediastinal mass was found to be in contact with the thymic gland. The mass weighed 270 g and measured 12.5 cm × 10 cm × 5 cm. The left thoracic cavity contained 2200 ml bloody pleural effusion and 200 g coagula due to hemorrhage from the tumor. Metastasized choriocarcinoma was seen in both lungs and the liver. High serum levels of human chorionic gonadotropin (HCG, 1 634 000 mIU/ml) and a decreased weight of the testes (2.0 g each) with Leydig cell hyperplasia/hypertrophy and the seminiferous tubules with hyaline ghost tubules or Sertoli cell only tubules were seen; other male reproductive organs were histologically normal. Although the serum testosterone level was within the normal range (5.75 ng/ml), luteinizing hormone (LH, 0.1 mIU/ml) and follicle-stimulating hormone (FSH, 0.3 mIU/ml) levels were decreased. High serum levels of HCG and characteristic testicular changes are drscribed.     

Ultrastructural, morphometric, and hormonal analysis of the effects of testosterone treatment on Leydig cells and other interstitial cells in young adult rats.

Early effects of testosterone (T) treatment on the ultrastructure of testicular interstitium were analyzed by morphometry. In T-treated young adult rats the T-LH feed-back loop functioned as expected and the marked increase in peripheral T caused almost complete depletion of peripheral LH. Even though the peripheral LH concentration was almost undetectably low, the Leydig cells maintained regulatory interactions with macrophages, peritubular myoid cells and with the seminiferous epithelium lining the tubular lumina as indicated by the high correlations of morphometric parameters between the Leydig and other cell types. The morphometric alterations in the ultrastructure of Leydig cells suggest that the seminiferous tubules may signal by releasing inhibitory paracrine factors affecting the morphology and function of Leydig cells in T-treated young adult rats. The morphometry of Leydig cells in T-treated young adult rats showed a significant quantifiable reduction in nuclei and organelles involved in steroid synthesis and this analysis also offers a good basis for elucidation of the early effects of testosterone in terms of its contraceptive function as well as of different toxic compounds on reproductive functions.     

Endothelin and endothelin receptors A and B in the human testis

 Human testicular capillaries interconnect Leydig cells and seminiferous tubules. Microcirculation and blood flow are therefore essential for the maintenance of spermatogenesis. The expression and the localisation of ET (endothelin) and its receptors in testicular tissue, in seminiferous tubules and in human testicular capillaries were studied. ET-1 mRNA was detected in whole testicular tissue and in seminiferous tubules whereas isolated testicular capillaries were negative. Big ET-1 (Big endothelin 1) and ET peptides were localised in Leydig and Sertoli cells whereas interstitial and intramural capillaries (within the lamina propria) remained unstained. ET was also found in mature spermatids. ET-A (endothelin receptor A) mRNA was detected in seminiferous tubules and whole testicular tissue whereas testicular blood vessels were negative. ET-A immunostaining was displayed in Leydig and Sertoli cells and in spermatids. ET-B (endothelin receptor B) mRNA was detected in whole testicular tissue, seminiferous tubules and in testicular capillaries. ET-B peptide was prominent in Leydig cells, peritubular cells, endothelial cells and pericytes of interstitial and intramural capillaries as well as in vascular endothelial and smooth muscle cells. From these results we conclude that ET produced in Leydig and Sertoli cells can act in a paracrine manner via ET-B on the human testicular microvasculature and the peritubular cells. The presence of both ET-A and ET-B in Leydig cells and of ET-A in Sertoli cells leads to the assumption that ET could influence these cells as an autocrine factor. Accepted: 9 October 1998     

Cell-cell interactions in the control of spermatogenesis as studied using leydig cell destruction and testosterone replacement

This review centers around studies which have used ethane dimethane sulphonate (EDS) selectively to destroy all of the Leydig cells in the adult rat testis. With additional manipulations such as testosterone replacement and/or experimental induction of severe seminiferous tubule damage in EDS-injected rats, the following questions have been addressed: (1) What are the roles and relative importance of testosterone and other non-androgenic Leydig cell products in normal spermatogenesis and testicular function in general? (2) What are the factors controlling Leydig cell proliferation and maturation? (3) Is it the Leydig cells or the seminiferous tubules (or both) which control the testicular vasculature? The findings emphasize that in the normal adult rat testis there is a complex interaction between the Leydig cells, the Sertoli (and/or peritubular) cells, the germ cells, and the vasculature, and that testosterone, but not other Leydig cell products, plays a central role in many of these interactions. The Leydig cells drive spermatogenesis via the secretion of testosterone which acts on the Sertoli and/or peritubular cells to create an environment which enables normal progression of germ cells through stage VII of the spermatogenic cycle. In addition, testosterone is involved in the control of the vasculature, and hence the formation of testicular interstitial fluid, presumably again via effects on the Sertoli and/or peritubular cells. When Leydig cells regenerate and mature after their destruction by EDS, it can be shown that both the rate and the location of regenerating Leydig cells is determined by an interplay between endocrine (LH and perhaps FSH) and paracrine factors; the latter emanate from the seminiferous tubules and are determined by the germ cell complement. Taken together with other data on the paracrine control of Leydig cell testosterone secretion by the seminiferous tubules, these findings demonstrate that the functions of all of the cell types in the testis are interwoven in a highly organized manner. This has considerable implications with regard to the concentration of research effort on in vitro studies of the testis, and is discussed together with the need for a multidisciplinary approach if the complex control of spermatogenesis is ever to be properly understood.     

Male reproductive tract lesions at 6, 12, and 18 months of age following in utero exposure to di(n-butyl) phthalate

In utero exposure of male rats to the antiandrogen di(n-butyl) phthalate (DBP) leads to decreased anogenital distance (AGD) on postnatal day (PND) 1, increased areolae retention on PND 13, malformations in the male reproductive tract, and histologic testicular lesions including marked seminiferous epithelial degeneration and a low incidence of Leydig cell (LC) adenomas on PND 90. One objective of this study was to determine the incidence and persistence of decreased AGD, increased areolae retention, and LC adenomas in adult rats following in utero DBP exposure. A second objective was to determine whether AGD and areolae retention during the early postnatal period are associated with lesions in the male reproductive tract. Pregnant Crl:CD(SD)BR rats were gavaged with corn oil or DBP at 100 or 500 mg/kg/day, 10 dams per group. Three replicates of rats (n = 30 rats per replicate) were exposed from gestation day 12 to 21 and the male offspring allowed to mature to 6, 12, or 18 months of age. Gross malformations in the male reproductive tract and histologic lesions in the testes were similar to those previously described. However, testicular dysgenesis, a lesion of proliferating LCs and aberrant tubules that has not been previously described in DBP-exposed testes, was diagnosed. The incidence of this lesion was approximately 20% unilateral and 7-18% bilateral in the high-dose group and was similar among all ages examined, implicating a developmental alteration rather than an age-related change. AGD and areolae retention were found to be permanent changes following in utero exposure to 500 mg/kg/day of DBP. Decreased AGD was a sensitive predictor of lesions in the male reproductive tract, relatively small changes in AGD were associated with a significant incidence of male reproductive malformations. In utero DBP exposure induced proliferative developmental lesions, some of which would have been diagnosed as LC adenomas by the morphological criteria set forth by the Society of Toxicologic Pathology. However, these lesions were dissimilar to traditional LC adenomas as the LCs were poorly differentiated and the lesions contained aberrant seminiferous tubules. While the morphology and incidence of this DBP-induced testicular developmental lesion has been fully characterized by this study, the detailed pathogenesis warrants further investigation.     

Evaluation of the Possible Protective Role of Quercetin on Letrozole-induced Testicular Injury in Male Albino Rats

Abstract

Background: The purpose of this study was to appraise the possible adverse effects of quercetin against the aromatase inhibitor letrozole-induced developmental toxicity potential in male Wistar rats.

Methods: Control male albino rats were received vehicles used for flavonoids and vehicle used for letrozole. The rats in the first experimental group received letrozole at 0.04?mg/kg body weight (bwt) for 3 months. The second experimental group was treated with the flavonoid quercetin by gavage at a dose of 50?mg/kg bwt for 10 consecutive days after letrozole administration.

Results: Major treatment-related effects of letrozole included a dose-dependent increase in hormone levels and lipid peroxidation following exposure to 0. 04?mg/kg letrozole; and severe abnormalities with severe cellular deformation and disorganization in both spermatogenic and interstitial cells. The seminiferous tubules of the testes of the animals given quercetin and letrozole exhibited a rather normal appearance and the measured hormone levels were restored to nearly the normal levels.

Conclusion: Exposure doses of letrozole that are equal to the daily recommended human dose has toxic effects on the spermatogenic lineage in rats, while simultaneous treatment of quercetin and letrozole could prevent the deleterious effects on testicular tissue caused by letrozole administration.     

Stage-Dependent changes in spermatogenesis and sertoli cells in relation to the onset of spermatogenic failure following withdrawal of testosterone

Rapid and complete withdrawal of intratesticular testosterone was achieved via the destruction of all Leydig cells with the specific Leydig cell cytotoxin ethane dimethanesulphonate (EDS). Restoration of testosterone levels was accomplished by administration of a single dose (25 mg) of testosterone esters (T) known to reverse the antispermatogenic effects of androgen withdrawal. Quantitation of the degenerating germ cells in cross sections of seminiferous tubules (ST) at stages IV–V, VII, IX, and X–XI of the spermatogenic cycle was used as a sensitive biological index of the effects of testosterone withdrawal and restoration upon the function of the Sertoli cells. Compared to control testicular tissues, the mean numbers of pyknotic germ cells per ST cross section at stages VII, IX and X–XI increased significantly (P < 0.01–0.001) between 4 to 8 days post-EDS treatment, but only in stage VII tubules was this trend reversed significantly (P < 0.005) within 2 days by T supplementation. In EDS-treated rats, stages VII, VIII, IX, and X-XI also exhibited significant (P < 0.05–0.001) increases (compared to controls) in the volumetric proportions by which intraepithelial vacuoles appeared within the seminiferous tubules. Again, in EDS+T supplemented rats, the appearance of vacuoles was significantly (P < 0.001) suppressed in stage VII and VIII. In contrast to tubules at stages VII-XI, those at stages IV–V were completely unaffected by testosterone withdrawal or replacement. The results show that at selected time intervals after EDS treatment, testosterone supplementation is capable of preventing/reversing these morphological changes within 2 days in stage VII tubules. It is suggested that the induction and subsequent prevention of seminiferous epithelial damage will serve as an important in vivo and in vitro approach for studies on the androgen-mediated changes in Sertoli cell biology during phases of impairment and recovery of their function. Manipulation of adult Sertoli cell function as provided by our model should permit identification of androgen-regulated gene products together with an understanding of their role(s) in normal and abnormal spermatogenesis. © 1993 Wiley-Liss, Inc.     

Testicular development in cynomolgus monkeys

The testes from 136 male cynomolgus monkeys were examined histopathologically in order to investigate the relationship between the development of spermatogenesis and testis weight, age, and body weight. At Grade 1 (immature), Sertoli cells and spermatogonia were the only cell classes in the testis. At Grade 2 (pre-puberty), no elongated spermatids were observed in the testis, although a few round spermatids and small lumen formation were observed. At Grade 3 (onset of puberty), all classes of germ cells were observed in the testis, although seminiferous tubule diameters and numbers of germ cells were small. Slight debris in the epididymis was observed in almost all animals. At Grade 4 (puberty), almost complete spermatogenesis was observed in the seminiferous tubules and it was possible to ascertain the spermatogenesis stage as described by Clermont, although tubule diameters and numbers of germ cells were small. There was less debris in the epididymis than at Grade 3. At Grade 5 (early adult), complete spermatogenesis was observed in the seminiferous tubules. At Grade 6 (adult), complete spermatogenesis in the seminiferous tubules and a moderate or large number of sperm in the epididymis were observed. Moreover, sperm analysis using ejaculated sperm was possible. Logistic regression analysis showed that testis weight is a good indicator of testicular maturity.     

Spontaneous and age-related testicular findings in beagle dogs

This study was conducted to characterize spontaneous testicular and epididymal microscopic findings in eighty control beagle dogs from toxicity studies. Hypospermatogenesis, characterized by randomly scattered missing spermatids and/or spermatocytes within seminiferous tubules, was observed in 75% of dogs six to seven months of age and declined to fewer than 10% in dogs over eleven months of age. Atrophy/hypoplasia of seminiferous tubules, characterized by subcapsular triangular clusters of tubules containing no germ cells, was observed in 25 to 40% of dogs under twelve months old, decreasing with age to 14 to 17% in dogs twelve to thirty-six months old. Retained spermatids, multinucleate giant cells, intracytoplasmic vacuoles (presumably in Sertoli cells), and swollen spermatocytes were common findings of minimal severity. Six- and seven-month-old dogs had lower testicular weights, less filling of the epididymal tails with sperm, and a two-fold higher incidence of abnormal epididymal content compared to dogs more than eight months of age. Most male beagles were histologically sexually mature by eight to nine months of age. This study confirms published reports that dogs at least ten months of age at necropsy usually are adequate for routine microscopic evaluation of the testes. If evaluation of spermatogenesis is critical, the incidental findings can be minimized by using males over twelve months of age.     

Testicular damage caused by inhalation of ethylene oxide in rats: light and electron microscopic studies.

Although testicular damage caused by ethylene oxide vapor (EtO) has been previously reported, the morphological changes occurring in seminiferous tubules remain unclear. We examined the time course of the testicular lesion induced by EtO in order to clarify its morphogenesis. Wistar rats were exposed to 500 ppm EtO for 6 hr per day, 3 times per week for 2, 4, 6, or 13 weeks through inhalation. In the 2-week exposure group, Sertoli cells often showed condensation and retraction of the cytoplasm, and dilatation of the endoplasmic reticulum (ER). In apical Sertoli cells, processes which encapsulated the heads of elongate spermatids, ectoplasmic specializations, and tubulobulbar complexes were often deformed and many elongate spermatids were degenerated. In the 4- and 6-week exposure groups, many degenerated Sertoli cells were present, and deformed germ cells, sometimes with multinucleation, appeared to make direct contact with each other without interlocation of Sertoli cell lateral processes. A few scattered immature Sertoli cells were evident in the 6-week exposure group. In the 13-week exposure group, seminiferous tubules containing almost all types of germ cells reappeared, mixed with atrophic tubules containing Sertoli cells only. In the former tubules, Sertoli cells often possessed regularly regenerated lateral processes, which were interposed between germ cells. These results indicate that the germ cell damage may be associated with damage to Sertoli cells. In spite of the intermittent exposure, focal regeneration of Sertoli cells appeared after 6 weeks of exposure to EtO and preceded patchy recovery of germ cells. Therefore, the data suggest that Sertoli cell regeneration may permit regeneration of germ cells.