Varicocele in the rat: a new experimental model. Effect on histology, ultrastructure and temperature of the testis and the epididymis

The effect of the degree of left renal vein constriction on the development of adolescent varicocele in Sprague-Dawley rats

Experimental models have allowed inquiry into the pathophysiology of varicocele (VC) beyond that possible with human patients. A randomized controlled study in rats was designed to clarify the influence of the degree of left renal vein constriction on the development of adolescent VC. Fifty adolescent male Sprague–Dawley rats (Rattus norvegicus) were randomly assigned to five groups of 10: the experimental groups (I–IV) underwent partial ligation of left renal veins with 0.5-, 0.6-, 0.7-, and 0.8-mm diameter needles, respectively. The control group (V) underwent a sham operation. The diameter of the left spermatic vein (LSV) was measured at baseline and 30 days postoperatively. In addition, the lesion of the left kidney was examined with the naked eye and assessed by Masson's trichrome staining. VC was successfully induced in 2 (20%), 4 (40%), 7 (70%), and 10 (100%) rats in groups I–IV, respectively. The other rats failed to develop VCs primarily due to left renal atrophy. No VC was observed in group V. The postsurgical LSV diameters in VC rats in groups III and IV were 1.54 ± 0.16 and 1.49 ± 0.13 mm, respectively (P > 0.05), and their increments were 1.36 ± 0.10 and 1.31 ± 0.10 mm, respectively (P > 0.05). These results suggest that suitable constriction of the left renal vein is critical for adolescent VC development. In addition, the 0.8-mm diameter needle may be more suitable for inducing left renal vein constriction in adolescent rat models.

Varicocele-caused progressive damage in bilateral testis and sertoli cell-only syndrome in homolateral testis in rats

Background

We aimed to investigate whether varicocele (VC) in rats can cause Sertoli cell-only syndrome (SCOS).

Material/Methods

Forty adolescent SD rats were randomly divided into 4 groups: 4-weeks control group, 4-weeks experimental group, 12-weeks control group, and 12-weeks experimental group. Left varicocele models were introduced by partially ligating left kidney veins for the experimental groups, and the sham surgery groups as controls were executed with exactly the same surgery as in the experimental groups except for the ligation. Rats in control and experimental groups for 4 and 12 weeks were killed after laparotomy at 4 and 12 weeks, respectively, the testes were taken out and fixed in fixative containing 4% polyformaldehyde, then were stained by hematoxylin and eosin (HE). The density and viability of sperm were analyzed by computer-aided sperm analysis.

Results

Compared with rats in 4-weeks and 12-weeks control group, histological structures of bilateral testes in both experimental groups were impaired, most of them showing as focal focuses. The pathological changes of testes in rats of the 12-weeks experimental group were bilateral, and included atrophy of seminiferous tubules, turbulence of spermatogenic cells in seminiferous tubules, defluvium of most spermatogenic cells, abortion of spermatogenesis, and degradation of spermatogenic epithelia. One rat in the 12-weeks experimental group was shown having SCOS, with the spermatogenic cells in seminiferous tubules completely flaked, degraded, or absent, and only Sertoli cells lined the seminiferous tubules.

Conclusions

Laboratory VC caused progressive impairment of homolateral testes, and SCOS could be induced when the damage was severe. Our results indicate that asthenozoospermia, azoospermia, and SCOS can be prevented by the earlier treatment of VC.

Harmful effects of carbamazepine on the postnatal development of the rat ventral prostate

BACKGROUND

Carbamazepine (CBZ) is a first-line antiepileptic drug (AED), although it is also used for the treatments of psychiatric disorders and neuropathic pain. The CBZ utilization has been associated with male reproductive damage, including hormonal alterations, sexual dysfunction and reduction of sperm quality. The wide and long-term use of the CBZ is a common schedule in children and adolescents and alters the testosterone level in adult rats and humans. The objective of this work was to evaluate the CBZ side effects on the ventral prostate of rats from pre-puberty to sexual maturation, since the prostate is an androgen-dependent organ.

METHODS

Twenty three day-old male albino Wistar rats received CBZ diluted in propylene glycol (20 mg/Kg/i.p via). The treatment lasted 20, 40 and 70 days, according to the different stages of the rat sexual maturation. At the end of each treatment period, ventral prostates were removed and histologically processed. The prostate sections were submitted to the histopathological, morphological and stereological analyses using image analysis system.

RESULTS

Reductions of the glandular epithelium, glandular lumen and fibromuscular stroma volume of the ventral prostate were observed in adult rats treated with CBZ since the weaning. Triggering and degranulation of mast cells were observed in the fibromuscular stroma of prepubertal and pubertal CBZ treated rats.

CONCLUSIONS

The results suggest a direct effect of the CBZ on rat ventral prostate, evidenced by increase of mast cell and macrophage populations during pre-puberty and puberty causing a ventral prostate accentuated damage in the adult phase.

The comparison of two experimental rat varicocele models and their effect on sperm quality

OBJECTIVE

To develop a modified rat varicocele model.

METHODS

300 male Sprague-Dawley rats were selected. In 82 rats (classic group, CG), this was achieved by dissecting the left renal vein and ligating it using a 0.8-mm metal clip and 3-0 silk suture proximal to the inferior vena cava, followed by removal of the bar. In 118 rats (modified group, MG), in addition to the partial ligation of the left renal vein, the communicating branch was fully ligated. In 100 rats (sham operation group, SG), the left renal vein and communicating branches were dissected, but not ligated. The seminal fluid was aspirated and the diameters of the left spermatic veins were analyzed. Three months later, the examination was performed again.

RESULTS

The diameters were 0.16 ± 0.1 mm and 1.88 ± 0.1 mm before and after operation, respectively, in the CG (p < 0.01), and 0.15 ± 0.05 mm and 2.0 ± 0.1 mm in the MG (p < 0.01). Postsurgical diameters in the CG and MG were 1.88 ± 0.1 mm and 2.0 ± 0.1 mm (p > 0.5), and 0.16 ± 0.1 mm and 0.16 ± 0.11 mm in the SG (p > 0.5). Semen parameters in the CG had significant differences before and after the operation (p < 0.01), were significantly lower in the MG (p < 0.01), and had no significant differences in the SG (p > 0.5).

CONCLUSION

Simple partial ligation of the renal vein combined with ligation of the communicating branch leads to acceptable models for varicocele.

Ghrelin attenuates heat-induced degenerative effects in the rat testis

This study was conducted to examine the efficacy of ghrelin in prevention of deleterious effects of heat stress in rat testicular tissue. Forty five adult male rats were scheduled for this study and were divided equally into three groups: heat-saline, heat-ghrelin and control-saline. The scrota of heated-designed rats were immersed once in water bath at 43 °C for 15 min. Immediately upon heating, 2 nmol of ghrelin were given subcutaneously to heat-ghrelin animals every other day up to day 60 and physiological saline to the other two groups using the same method. The animals were sacrificed at 10, 30 and 60 days after heat treatment and their testes were taken for later photomicrograph and immunohistochemical analysis. Testicular histopathology revealed a significant reduction in the means of seminiferous tubules and Sertoli cell nucleus diameters as well as germinal epithelium height on day 10 in both heated groups. Furthermore, other testicular components including miotic index, spermatogenesis rate, presence of spermatocytes and volume densities were dramatically decreased following heat exposure. Notably, ghrelin caused a partial recovery in all of the above-mentioned parameters and accelerated testicular regeneration process by day 30 compared to the heat-saline group (P<0.05). Because of testicular progressive recovery, these indices were similar among groups on day 60 (P>0.05). However, immunohistochemistry evaluation for in situ detection of Bcl-2 protein did not exhibit any germ cells-positive of this factor among groups at different experimental days. In conclusion, the results of the present study indicate for the first time the novel evidences of ghrelin ability in attenuation of heat-induced testicular damage and also that ghrelin therapy may be useful as a suppressor of degenerative effects following testicular hyperthermia.

Sertoli cell morphological alterations in albino rats treated with etoposide during prepubertal phase

Sertoli cells are very important to spermatogenesis homeostasis because they control germ cell proliferation, differentiation, and death. Damages to Sertoli cells cause germ cell death and affect fertility. Etoposide is a potent chemotherapeutic drug largely used against a variety of cancers. However, this drug also kills normal cells, especially those undergoing rapid proliferation. In the testis, etoposide acts predominantly on intermediate and type B spermatogonia. Etoposide was shown to permanently alter Sertoli cell function when administered to prepubertal rats. Based on this, we decided to investigate whether etoposide can affect Sertoli cell morphology. For this, 25-day-old rats were treated with etoposide during 8 consecutive days and killed at 32, 45, 64, 127, and 180 days old. Testes were fixed in Bouin's liquid or in a mixture of 2.5% glutaraldehyde and 2% formaldehyde for analysis under light and electron microscopes, respectively. Sertoli cells showed morphological alterations such as the presence of chromatin clumps close to the nuclear membrane, nucleus displacement, and cytoplasmic vacuolization. Some Sertoli cells also showed nuclear and cytoplasmic degenerative characteristics, suggesting that etoposide causes severe damages to Sertoli cell.

Effects of laparoscopic division of spermatic vessels on histological changes of testes: long-term observation in the model of prepubertal rat

Laparoscopic Fowler-Stephens and Palomo procedures are now commonly performed in children with high positioned intra-abdominal cryptorchidism and varicocele, respectively. During the procedures, the spermatic vessels are ligated and therefore the question of risk related to testicular atrophy is often raised. The long-term follow-up of the histology after the procedures is rare. In this study, we simulated a laparoscopic spermatic vessels clipping and division (SVCD) in a prepubertal rat model, and examined the histological alterations of the testes with regard to spermatogenic arrest between prepuberty and middle age. Thirty-day-old Wistar rats divided randomly into three groups underwent laparoscopic sham operation, unilateral SVCD and unilateral SVCD with additional contralateral orchiectomy, respectively. Histological investigations observed on semithin and paraffin sections were performed at seven different postoperative intervals between day 9 and day 540. We defined partial, most and complete spermatogenic arrest of the seminiferous tubules to correspond with mild, severe spermatogenic arrest and atrophy, respectively. Laparoscopic SVCD induced testicular spermatogenic arrest in a total of 85% of the operated testes with different severity; 27% of operated testes with mild or severe spermatogenic arrest were seen between puberty and middle age (day 45-540 postoperative), and their size was only slightly reduced. Of the operated testes, 51% showed atrophic signs with a striking decrease in size, and their contralateral testes revealed in all cases mild or severe spermatogenic arrest started as early as day 45 postoperatively. Parallel to the spermatogenic arrest, Leydig cell hyperplasia developed frequently in impaired testes, especially in those without contralateral testes, finally reaching a typical adenoma size. Laparoscopic SVCD in prepubertal rats could disturb spermatogenesis with differing severity in most cases. This impairment could persist from peripuberty to middle age, and even involve the contralateral testes, in the case of operated testes and show complete spermatogenic arrest. This study showed that laparoscopic SVCD may have high risk in compromising the operated testis.

Effects of epidermal growth factor on sperm content and motility of rats with surgically induced varicoceles

AIM

To investigate the effect of epidermal growth factor (EGF) on the sperm content and motility of the varicocelized rats.

METHODS

Forty-eight male Wistar rats were randomly divided into five groups. Experimental varicocele was induced by partial ligation of the left renal vein in the varicocele, the varicocele repair, the varicocele with EGF and the varicocele repair with EGF groups, whereas the control group only received a sham induction of varicocele. Surgical repair of varicocele was performed 4 months later in the varicocele repair and varicocele repair with EGF groups. EGF administration was performed daily by s.c. injection in the varicocele with EGF and varicocele repair with EGF groups at the dose of 10 microg/(kg.day) from the next day of the second surgery. One month later, all animals were killed and bilateral cauda epididymal sperm counts and motility were evaluated.

RESULTS

The mean sperm count and percentage of motile spermatozoa were significantly higher bilaterally in the varicocele with EGF group than in the varicocele group (P < 0.05). They were also significantly higher bilaterally in the varicocele repair with EGF group than in the varicocele repair and the varicocele with EGF groups (P < 0.05).

CONCLUSION

EGF can improve bilateral epididymal sperm content and motility of the rat with surgically induced varicocele. The administration of EGF in combination with surgical repair is more effective than surgical repair or EGF administration alone. EGF might be useful for the treatment of infertility induced by varicocele.

The Fas system may have a role in male reproduction

OBJECTIVE

To assess what the distributions of Fas system proteins are in normal rat testicular tissue; to assess whether there is a change in these distributions and in expression levels with experimentally-induced varicocele of 9, 11, and 13 weeks; and to assess whether there is a relationship between apoptosis and the Fas system in varicocele-induced rat testis.

DESIGN

Comparative and controlled study.

SETTING

University animal care and operation unit.

ANIMAL(S)

Wistar male rats for experimental and control groups.

INTERVENTION(S)

The control group underwent sham operation (n = 6). Rats in experimental groups underwent partial ligation of the renal vein to induce an experimental varicocele and then were killed at 9 (n = 6), 11 (n = 6), and 13 (n = 6) weeks after induction of varicocele.

MAIN OUTCOME MEASURE(S)

Tissues were fixed and processed for paraffin and Araldite embedding, and subsequently immunohistochemistry, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling, and transmission electron microscopy were performed. In addition, Western blotting was applied.

RESULT(S)

In control testis, we detected the expression of FasL in spermatids, interestingly at the progressing stages of acrosome formation and in the heads of the spermatozoa being released to lumen. Varicocele induction revealed a significant down-regulation of this protein, especially 11 weeks after the operation, without altering its distribution. Fas protein was present in cytoplasmic extrusions of the elongated spermatids and evidently in Leydig cells of the interstitial tissue. The expression of Fas protein was diminished after 11 weeks of varicocele induction, both in Leydig cells and in cytoplasmic extrusions. The decrease of Fas was significant in the 13-week-old varicocele group, whereas that of FasL was significant in the 11-week-old varicocele group. Compared with sham-operated animals, a minor increase in the number of apoptotic germ cells in varicocele groups was detected.

CONCLUSION(S)

Our results exposed other possible important roles of the Fas system in addition to than apoptosis in male reproduction. We suggest that the role of the Fas system needs further investigation both in animal models and in human male infertility.

Sertoli cell function in albino rats treated with etoposide during prepubertal phase

Sertoli cell plays a key role in spermatogenesis. Many studies refer that this cell is not harmed by the majority of anticancer treatments known to cause damage to the testis. However, in the previous study we observed that etoposide, an efficient chemotherapeutic drug, provokes an increase in numerical density of the Sertoli cells. This phenomenon suggests that this cell was harmed by etoposide. Thus, we decided to investigate a possible direct action of etoposide on Sertoli cells analyzing the function of this cell and relating it with the integrity and damage of the seminiferous epithelium. Prepubertal albino rats received 5 mg/kg of etoposide for eight consecutive days and were sacrificed in different ages. The control groups received 0.9% saline solution. The testes were fixed in Bouin's liquid for transferrin immunolabeling and testicular labeled tissue volume density measurement. Except for the younger rats, all the etoposide-treated rats showed diminution of transferrin immunolabeling in the seminiferous epithelium, and consequently, of total labeled testicular tissue volume density. We concluded that the diminution of transferrin labeling in the seminiferous epithelium was not associated with germ cell absence such as commonly reported. The results suggest etoposide impairs Sertoli cell function.

Do experimentally induced ipsilateral testicular torsion, vas deferens obstruction, intra-abdominal testis or venous obstruction damage the contralateral testis through a common mechanism?

OBJECTIVE

To evaluate if various conditions affecting the ipsilateral testis which also damage the contralateral testis share a common pathway for their effects.

MATERIALS AND METHODS

The study comprised five groups of 10 adult rats which underwent surgery to produce (on their left sides); group 1, a sham operation (control); group 2, testicular torsion; group 3, vas deferens obstruction; group 4, an intra-abdominal testis; and group 5, venous obstruction. The ipsilateral and contralateral testes were harvested 4 weeks after surgery. The relative proportions of haploid cells, the mean seminiferous tubular diameter (MSTD), mean testicular biopsy scores (MTBS), and lactate and hypoxanthine levels were determined and compared.

RESULTS

The proportions of haploid cells in the ipsilateral and the contralateral testes of groups 2-5 were significantly lower than those of the corresponding testes of the control group. The MSTD and MTBS of the ipsilateral testes in groups 2-5 were also significantly lower than the ipsilateral testes of controls and the contralateral testes within the same groups. While the MSTD and MTBS of the contralateral testes of groups 1 and 5 were not significantly different, those of the contralateral testes of groups 2-4 were significantly less than that of group 1. The lactic acid and hypoxanthine levels of the ipsilateral and contralateral testes were significantly increased in groups 2 and 3. While only the hypoxanthine level of group 5 increased significantly, both variables were not significantly different between the ipsilateral testes of groups 1 and 4.

CONCLUSIONS

These four treatments damaged both the ipsilateral and contralateral testes. As the lactic acid and hypoxanthine levels within the contralateral testis were greater than in the controls, testicular torsion and vas deferens obstruction seem to share a common pathway (which may be a reflex decrease in contralateral testicular blood flow) for their effects on the contralateral testis.

Role of radical oxygen species in rat testicular germ cell apoptosis induced by heat stress

The present study was designed to clarify the role of radical oxygen species in testicular germ cell apoptosis induced by heat stress. Testicular cells isolated from immature rats were cultured with or without elevated temperature, and occurrence of apoptosis in these cells was defined by the appearance of DNA fragmentation following agarose gel electrophoresis and by flow cytometric quantification of apoptotic cells. At 32.5 degrees C, < 1% of cells showed signs of apoptosis throughout the culture period, whereas under heat stress, the proportion of apoptotic cells increased to 5% at 37 degrees C after 24 h of culture, or to 14% after 1-h exposure at 43 degrees C followed by 23-h culture at 32.5 degrees C. Similar to the effect of heat stress, exogenously supplied oxygen free radicals also induced apoptosis. In contrast, treatment with catalase significantly attenuated heat stress-induced apoptosis. Furthermore, heat stress of testicular cells was associated with an increased intracellular peroxide level as measured by a fluorescent probe, 2', 7'-dichlorofluorescin diacetate. In conclusion, our data indicate the involvement of radical oxygen species during testicular germ cell apoptosis induced by heat stress. This study provides a useful in vitro model for the study of testicular germ cell apoptosis.

Ligation of the left renal vein in epm1-Wistar rats: functional and morphologic alterations in the kidneys, testes and suprarenal glands

OBJECTIVE

The ligation of the left renal vein (LLVR) in man is a controversial procedure in view of the risks of lesion to the renal parenchyma. With the objective of studying the morphologic and functional alterations caused by these lesions, we conducted experimental research with rats.

MATERIAL AND METHODS

64 male adult EPM1-WISTAR rats were used, divided into 8 groups-4 for LLRV and four for control. Each LLRV group and corresponding control group were sacrificed progressively on the 7th, 15th, 30th and 60th day after the initial surgery.

RESULTS

We found morphofunctional alterations only in animals that underwent LLRV in the four periods of sacrifice. The proteinuria creatinine in serum, testosterone in serum and serum corticosterone in serum showed practically no alteration in relation to the normal values for rats. Statistically significant severe histological lesions were found in the kidneys and testes of the LLRV groups. Lesions in the suprarenal glands were also present in these groups, but no sufficient to demonstrate statistical significance.

CONCLUSION

Based on these results we can conclude that the ligation of the left renal vein is a procedure of high risk in these animals.