The venous anatomy of experimental left varicocele: comparison with naturally occurring left varicocele in the human

Sertoli Cell Alterations in Peripubertal Varicocelized Rats: Evidence of Primary Damage on Spermatogenesis

Idiopathic varicocele is closely associated with male infertility or subfertility. Sertoli cell is a very important regulator of spermatogenesis. We investigated the morphofunctional alterations in the Sertoli cell and its possible involvement in the establishment of testicular primary lesion in experimental left-sided varicocele, induced from peripuberty. Twenty-five male peripubertal rats (44 days postpartum [dpp]) were distributed into two groups: control (C) and varicocele (V). Experimental left varicocele was induced in rats through the partial ligature of the left renal vein. Euthanasia was performed at 100 dpp. Testicular histopathology and testosterone plasmatic level were evaluated. Transferrin and vimentin proteins were, respectively, used as immunomarkers of Sertoli cell function and structure. Significant reductions in vimentin and transferrin expressions were noticed in androgen-dependent stages (VII and VIII) of the seminiferous epithelium cycle in V rats; testosterone plasmatic level was also reduced. Bilateral testicular histopathological alterations were found in V rats, mainly massive germ cell desquamation. The histological damage and changes in protein expressions occurred bilaterally. The relevant impairment of the functional and structural characteristics of the Sertoli cell, together with the typical massive germ cell desquamation, indicates that Sertoli cell changes can primarily contribute to the significant testicular dysfunction associated with varicocele.

With a new clip technique surgically inducing varicocele in Sprague-Dawley rats

BACKGROUND

We introduced and recreated a more consistent and effective experimental varicocele rat model by a new clip technique.

METHODS

A total of 40 rats were numbered and randomly assigned to 5 groups of 8 each, including sham surgery (Group I), conventional (Group II) and clip groups with 0.7, 0.8, 0.9 mm gap widths, respectively (Group III, IV, V). All of the rats in each group were sacrificed at 8 weeks after initial surgery, and the rats forming out with less than 1 mm diameter of left spermatic vein or no presence of the pampiniform plexus dilation were excluded from the experimental groups. The left spermatic vein (LSV) diameter, testicular weight, left kidney weight to body weight coefficients, kidney and testicular histology were determined.

RESULTS

The baseline mean diameter of the LSV in Group I, II and III was 0.22 ± 0.02, 0.23 ± 0.02 and 0.22 ± 0.03 mm, respectively (P = 0.7504). At 8 weeks after initial surgery, varicocele was successfully created in 6/8 (75%), 7/8 (87.5%), 3/8 (37.5%), 3/8 (37.5%) in GroupII-V, no varicocele was observed in Group I. In Group I, II and III, no pathological changes were observed and the left kidney weight to body weight coefficients showed no significant differences. The diameter of LSV was remarkably increased both in Group II and III compared to Group I (1.72 ± 0.13, 1.57 ± 0.19 and 0.25 ± 0.02, respectively), and Group II and III had a smaller testicular weight than the rats in Group I (1.67 ± 0.05, 1.62 ± 0.06, and 1.92 ± 0.12, respectively).

CONCLUSIONS

With a new clip technique, surgically inducing varicocele rat model becomes convenient and safe. This appears to improve the effectiveness of the model and this innovation may allow us to further understand the pathophysiology of varicocele.

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.

The role of animal models in the study of varicocele

Varicocele is the most common correctible cause of male infertility and is present in 15% to 20% of the male population. Despite its prevalence, the pathophysiology of varicocele remains under investigation. One of the largest obstacles in studying varicocele is that it is almost exclusively found in humans. This has necessitated the creation of an animal model of varicocele. The most commonly used animal model involves the creation of a varicocele in a rodent by partially occluding the left renal vein. This model has provided a significant amount of data on varicocele, and a modification of this model utilizing microsurgery appears even more promising. Animal models have proven critical to investigating the pathophysiology of varicocele.

Is the comparison of a left varicocele testis to its contralateral normal testis sufficient in determining its well-being?

OBJECTIVE

To determine whether a size difference between a left testis involved with a varicocele and the contralateral normal testis is sufficient in its size assessment.

METHODS

We reviewed all pediatric scrotal ultrasounds at Helen DeVos Children's Hospital between 2001 and 2008. Sonographic testicular measurements were recorded for patients with clinically diagnosed left varicocele (n = 81 for "varicocele" group) and for patients with no specific pathologic findings (n = 184 for "normal" group). We first compared the sizes between left and right testes for all patients, then between the "varicocele" group and the "normal" group separately for left and right.

RESULTS

There were no significant size differences between left and right testes for the "normal" group, whereas the left was significantly smaller than the contralateral right for the "varicocele" group (P = .0048 for length; P = .012 for volume) for all ages. For boys 16 years or older, both the left and contralateral right testes of "varicocele" boys were smaller than those of "normal" boys, adjusting for age (P for left = .026 for length and .059 for volume; for right P = .033 for length and .031 for volume).

CONCLUSION

Our study confirms that the left testis in boys with varicocele is most often smaller than the contralateral right testis no matter the age. Compared with normal boys in late adolescence, the contralateral right testis is smaller in boys with varicocele.

Effects of varicocele on testosterone, apoptosis and expression of StAR mRNA in rat Leydig cells

The aim of this study was to explore the effects of varicocele on the morphology and function of Leydig cells in the rat testis. Forty male Sprague-Dawley rats were divided into two groups: the experimental group underwent surgery to create a left varicocele (VC), and the control group underwent a sham operation. Serum testosterone and intratesticular testosterone levels were measured using a radioimmunoassay after 4 and 8 weeks of operation. Leydig cells were studied for apoptosis and expression of steroidogenetic acute regulatory (StAR) protein mRNA levels. Serum testosterone levels declined after 4 and 8 weeks of operation but were not significant (P>0.05). However, the intratesticular testosterone levels after 8 weeks were significantly decreased compared with the control group (P<0.01). The mean apoptosis index of Leydig cells in the experimental group was significantly higher than that in the control group after 4 or 8 weeks (P<0.01). StAR mRNA levels in the Leydig cells of the experimental group were significantly lower compared to those of the control group (P<0.01). Our data show that varicocele did impair Leydig cell function by increasing apoptosis and suppressing the expression of the StAR protein.

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.

Experimental varicocele in the rat: early evaluation of the nitric oxide levels and histological alterations in the testicular tissue

The relationship between varicocele and male infertility remains to be explained. Oxidative damage because of the testicular venous backflow may represent one of the causes of gonad injury and seems to precede the histological alteration. Therefore measuring the values of spermatic or intratesticular nitric oxide (NO) could be useful in evaluating this oxidative distress. The aim of this study is to assess the role of testicular NO in early detection of the damages induced by an experimental varicocele in the Wistar rat. A left varicocele was induced in 10 animals (group A). A control group of 10 rats was performed (group B). Animals were killed 3 months after the operation. Both testicles were harvested, weighed and sectioned in two equal parts: one for the evaluation of the NO level and the other one for histological examination. All the rats in group A showed a conspicuous dilatation of the left spermatic vein. The histopathological analysis was normal in both the groups. Biochemistry showed a meaningful statistical difference (P < 0.001) in the concentrations of NO among the specimens of the left and right gonads in group A but no difference was found in group B. The increase in NO values and the presence of other oxidant agents represent the first sign of testicular distress and it seems to anticipate histopathological changes. As it is well known that a great difference exist between human and animal sperm, NO could therefore in the future be taken into consideration together with others parameters for the evaluation of patient who is affected by varicocele.

Improvement in the fertility rate after placement of microsurgical shunts in men with recurrent varicocele

OBJECTIVE

To evaluate the effectiveness of microsurgical shunts for secondary varicocele repair after ligation-like procedures, focusing on long-term functional outcomes.

DESIGN

Long-term survey (mean follow-up, 8.5 years) of infertile men after secondary microsurgical reconstructive varicocelectomy.

SETTING

University-based medical center.

PATIENT(S)

Thirty-four infertile men (group A, <30 years of age; and group B, >30 years) with recurrent palpable varicocele after varicocelectomy, according to Ivanissevich (n = 28), or after angiographic vein occlusion (n = 6). Ten patients presented bilateral recurrence.

INTERVENTION(S)

Microsurgical shunts between spermatic vein and inferior epigastric vein.

MAIN OUTCOME MEASURE(S)

Sperm count, pregnancy rate, and ultrasound evaluation of varicosity.

RESULT(S)

Complete disappearance of varicosity was achieved in 97.06% of patients, while in 2.94%, a consistent reduction in size was observed. In patients with severe infertility, a significant postoperative increase in seminal parameters was observed. Pregnancy rates were 43.75% in group A and 22.22% in group B.

CONCLUSION(S)

Microsurgical drainage in patients with recurrent varicocele after ligation-like procedures was shown to be an effective minimally invasive treatment, with immediate hemodynamic recovery of testicular venous outflow and excellent long-term results in patients with left or bilateral recurrences.

The changes in testicular vascular permeability during progression of the experimental varicocele

OBJECTIVES

The vascular permeability of testicular capillaries which play a role in controlling the formation of testicular interstitial fluid was studied during the progressive course of experimental varicocele.

MATERIALS AND METHODS

The pathology was developed through partial ligation of left renal vein in four groups of rats. Controls of each group were subjected to sham surgery. After different periods of varicocele creation (1, 3, 6 and 14 weeks), animals' testes per one of the study groups were extirpated and weighed. The volume density percentages of polymorphnuclear leukocytes (PMN) per testicular blood vessels; which are markers of the increase in vascular permeability, were also estimated in both testes. To further verify the obtained findings, another group of animals received human chorionic gonadotrophin (hCG) treatment 6 weeks after varicocele creation and their histopathological sections were examined.

RESULTS

Animal testes' of (1 and 3 weeks) groups were found to be significantly heavier (p<0.05) than their controls. PMN showed accumulation in testicular blood vessels and their volume density percentages per these blood vessels in both testes were significantly higher in each study group than in those of its controls. However, these percentages showed gradual significant decline as the duration of varicocele bearing gradually increased. The hCG-treated animals revealed more accumulation of the PMN in their histopathological sections.

CONCLUSION

The present results suggest that experimental varicocele may induce an increase in testicular vascular permeability, which then decreases gradually with time. It is supposed that parallel changes in the rate of formation of testicular interstitial fluid may be accompanied. The results have also showed that the vasculature of the testis with experimental varicocele can still respond to hCG.

Effect of experimental varicocele in rats on testicular oxidative stress status

The present experiments were undertaken to determine the levels of MDA, SOD and catalase in the testis of adolescent rats with experimental left varicoceles. Male Wistar rats, 7 weeks old and weighing 160-170 g, were randomly allocated into three groups. The first group of rats underwent partial ligation of the left renal vein (n = 15). The second group of rats underwent a sham operation (n = 7) and the third group acted as controls (n = 7). Animals were sacrificed 6 weeks after surgery and dilatation of the internal spermatic veins was observed. Levels of MDA, SOD and catalase activity were measured in testis. The experimental left varicocele group showed severe testicular changes compared to other groups. The mean MDA (SEM) levels in right and left testicular tissues of varicocele bearing rats, sham-operated rats, and control rats were 0.48 +/- 0.24 and 0.31 +/- 0.11, 0.22 +/- 0.02 and 0.35 +/- 0.12, 0.62 +/- 0.29 and 0.13 +/- 0.05, respectively (P > 0.05). The mean SOD (SEM) levels in right and left testicular tissues of varicocele bearing rats, sham-operated rats, and control rats were 7,790 +/- 606 and 6,974 +/- 574, 7,475 +/- 1,517 and 7020 +/- 1,106, 8,727 +/- 1,188 and 9,019 +/- 1,129, respectively (P > 0.05). The mean catalase (SEM) levels in right and left testicular tissues of varicocele bearing rats,sham-operated rats, and control rats were 75.77 +/- 11.5 and 53.82 +/- 10.1, 91.94 +/- 14 and 94.90 +/- 32, 65.40 +/- 5.7 and 90.93 +/- 16.4, respectively (P > 0.05). Our results suggest that oxidative status, which reflects a relative balance between reactive oxygen species (ROS) generated and ROS scavenged, may not be responsible for the testicular dysfunction associated with experimentally induced varicocele during adolescence in rats.

Recurrence of varicocele after high retroperitoneal repair: implications of intraoperative venography

PURPOSE

We determined whether intraoperative venography results in a decreased recurrence rate after varicocele repair in adolescence.

MATERIALS AND METHODS

We evaluated 177 male adolescents 14 to 19 years old who underwent varicocele repair via the high retroperitoneal approach with artery sparing and intraoperative venography.

RESULTS

Overall the recurrence rate was 2.8% (5 of 177 cases) in the venography group and 11% in historical controls without venography. We identified left-to-right cross communicating vessels in 3 patients with recurrence. Intraoperatively venography revealed nonligated vessels in 21 patients (12%), resulting in revision and repair during the same procedure.

CONCLUSIONS

Intraoperative venography seems to decrease the rate of recurrence. Left-to-right cross communicating vessels may be present in some adolescents with recurrence after varicocelectomy.

Effect of surgically induced varicocele on testicular blood flow and Sertoli cell function

OBJECTIVES

To evaluate the effect of varicocele on testicular blood flow and expression by Sertoli cells of transferrin and androgen-binding protein (ABP), to determine whether varicoceles impair Sertoli cell function.

METHODS

Experimental varicocele was established in male Sprague-Dawley rats by partial ligation of the left renal vein. The control group received a sham operation. At 30 minutes after surgery, rats underwent a xenon-133 washout study, and at 30 days after surgery, transferrin, ABP, and testicular blood flow were evaluated. Expression of transferrin and ABP were evaluated using immunohistochemical techniques. Testicular blood flow was measured using xenon-133 clearance techniques. Statistical analyses were done with an independent t test.

RESULTS

The testicular blood flow was 16.7 +/- 1.25 mL/100 g/min in varicocele-bearing rats and 21.01 +/- 0.46 mL/100 g/min in sham-operated rats 30 minutes after surgery. Testicular blood flow remained decreased at 30 days in varicocele-bearing rats (15.12 +/- 1.08 mL/100 g/min) and remained stable in the control group (19.45 +/- 0.55 mL/100 g/min). The expression of transferrin and ABP was significantly reduced in varicocele-bearing rats compared with the control group.

CONCLUSIONS

Our study suggests that a decrease in testicular blood flow may lead to impaired Sertoli cell function in varicocele-bearing rats.

Testicular vascular permeability: effects of experimental lesions associated with impaired testis function

PURPOSE

Pathologies like varicocele and testicular torsion are known to alter testicular blood flow, either acutely or chronically. The present study was undertaken to determine whether or not alterations in testicular vascular permeability accompany these changes in testicular blood flow.

MATERIALS AND METHODS

Testicular vascular permeability was examined by determining the appearance of radiolabelled molecules (m.w. = 18 to 70,000) in testicular interstitial fluid after acute infusion into the proximal testicular artery of the rat. These vascular permeability studies were carried out in control animals, in those with 30 day experimental left varicocele (ELV), or in those having experienced a 1 hour, 720 degrees experimental torsion either 1 hour or 24 hours prior to the study.

RESULTS

Experimental left varicocele did not alter vascular permeability to the molecules studied, but 1 hour torsion did cause a significant increase in vascular permeability within 24 hours after repair of the torsion.

CONCLUSION

Alteration in vascular permeability is one of the family of events contributing to cell death after repair of experimental testicular torsion, but is not a factor in the pathobiology of experimental varicocele.