Induced Varicoceles in Rhesus Monkeys*†*Publication No. 993 from the Oregon Regional Primate Research Center. Supported in part by National Institutes of Health Grants HD05969 and RR00163.†Presented at the Thirty-Fourth Annual Meeting of The American Fertility Society, March 29 to April 1, 1978, New Orleans, La. ACMI Prize Paper

Characterization of varicocele-induced animal models: Potential role of inflammasome complex in the varicocele pathophysiology

Varicocele mechanisms and its impact in testicular dysfunction has been studied in order to understand the pathophysiology involved in this disease. However, study designs using testicular tissues from varicocele patients are restricted due to ethical limitations. Therefore, the use of animal models, mainly rats, that mimics varicocele and its effects is an option to develop new approaches. The surgical technique, that induces the varicocele in rats, is based on the partial obstruction of the left renal vein, leading to a dilation in the left spermatic vein and consequently to the pampiniform plexus, resulting in varicocele-induced condition. Thus, the study of the cellular and molecular mechanisms involved in varicocele development can be addressed in depth. Besides the animal model goal to uncover the exact varicocele pathophysiology, varicocele induced models are the best options to develop new non-surgical and less invasive therapies. Various animal model studies designed and investigated antioxidant and anti-inflammatory agents to face varicocele conditions. Minding this fact, we tried to discuss a newly uncovered complex in varicocele condition, known as inflammasome complex. Taking into consideration the possible inflammatory state present in varicocele, the inflammasome complex has been proposed to be involved in the pathophysiology of this disease.

Outcomes of experimental rat varicocele with and without microsurgery

BACKGROUND

Experimental rat varicocele was usually developed by the conventional technique but with varied success; and microsurgical rat varicocele model was an effective alternative. In this study we further analyzed differential outcome of experimental rat model with and without microsurgery.

METHODS

One hundred and twenty male Sprague-Dawley rats were randomly assigned to two groups. In Group A, experimental rat varicocele model was developed with conventional technique. The left renal vein was partially ligated with concurrent ligation of communicating branches between the left spermatic vein and common iliac vein. In Group B, all the above procedures were finished with microsurgical manipulation under operating microscope. Before and after model development, the mean diameter of the left internal spermatic vein was compared; and at 8 weeks after initial surgery the mean sperm concentration and motility in both groups was analyzed.

RESULTS

The baseline mean diameter of the left internal spermatic vein in Group A and Group B was 0.14 ± 0.04 and 0.15 ± 0.03 mm, respectively (P =0.3157). In Group A 9 rats had severe complications resulting in model failure; while in Group B all rats had successful model except for one died of anesthetic accident (P = 0.008). At 8 weeks after initial surgery the mean left internal spermatic vein, sperm concentration and motility in both groups was 1.65 mm, 321.5 × 10(6)/gm and 51.9%; and 1.65 mm, 318.9 × 10(6)/gm and 53.5% respectively. There was nonsignificant difference of internal spermatic vein diameter, sperm concentration and motility between two groups.

CONCLUSIONS

Microsurgery makes developing experiment rat varicocele model easy. Compared with conventional technique, microsurgical rat varicocele model has higher success rate and less complication.

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.

The effect of the partial obstruction site of the renal vein on testis and kidney in rats: is the traditional animal model suitable for varicocele research?

PURPOSE

We investigated the influence of the location of the partial renal vein obstruction on the left kidney, the bilateral testes, and cauda epididymal sperm quality and determined whether this animal model is suitable for varicocele study.

MATERIALS AND METHODS

A total of 25 adult male Sprague-Dawley rats were assigned to three groups: group 1 (experimental varicocele by partial ligation medial to the internal spermatic vein for 8 weeks, n=8), group 2 (partial ligation lateral to the internal spermatic vein for 8 weeks, n=10), and group 3 (sham operation for 8 weeks, n=7). Rats in groups 1, 2, and 3 underwent a left nephrectomy and bilateral orchiectomy at 8 weeks after the operation. Histological changes and Johnsen score in both testes were analyzed. Fibrotic changes in the left kidney were assessed by quantitative image analysis. Numbers of sperm and proportions of motile sperm in the cauda epididymides were determined.

RESULTS

Significant histological abnormalities and Johnsen score changes were observed in the testes in group 1. Renal fibrosis did not differ significantly among the groups. The proportions of motile sperm were significantly lower bilaterally in group 1 than in groups 2 and 3. However, the mean bilateral epididymal sperm count in group 1 was not significantly lower than in groups 2 and 3.

CONCLUSIONS

Our results showed that experimental varicocele in the rat, induced by partial ligation medial to the internal spermatic vein, influences epididymal sperm quality without harmful effects on the left kidney. The present study certifies that this traditional animal model is suitable for varicocele research.

The influence of left renal vein entrapment on outcome after surgical varicocele repair: a color Doppler sonographic demonstration

OBJECTIVE

To evaluate the impact of left renal vein entrapment on outcome after surgical varicocele repair using color Doppler sonography.

METHODS

Eighty-four men had varicoceles on color Doppler sonography (2 right sided, 74 left sided, and 8 bilateral), which were diagnosed on the basis of a venous diameter of 3 mm or greater and venous retrograde flow in the pampiniform plexus of veins during the Valsalva maneuver or when changing from a supine to an upright position. Diagnosis of the left renal vein entrapment was based on the following criteria: antero-posterior diameter of greater than 1 cm and peak velocity of less than 15 cm/s for the left renal vein at the mid portion and anteroposterior diameter of less than 0.2 cm and peak velocity of greater than 110 cm/s (or, alternatively, a diameter ratio and peak velocity ratio of >5) for the left renal vein between the aorta and superior mesenteric artery. All patients underwent surgical varicocele repair. In postoperative follow-up, we compared the presence of left renal vein entrapment with the frequency of varicocele recurrence.

RESULTS

Sixteen (19%) of 84 patients had left renal vein entrapment with a left-sided varicocele. Postoperatively (mean follow-up +/- SD, 19.3 +/- 11.7 months), 27 (32.2%) of 84 had varicocele recurrence, including all 16 patients with left renal vein entrapment and 11 (20.1%) of 68 patients without left renal vein entrapment. The varicocele recurrence rate was significantly greater in patients with left renal vein entrapment (P < .001, Fisher exact test).

CONCLUSIONS

The presence of left renal vein entrapment resulted in a significantly higher varicocele recurrence rate. Patients with varicoceles should routinely be evaluated for the presence of left renal vein entrapment before surgical repair.

The adolescent varicocele: treatment and outcome

At present, it is reasonable to counsel all patients, as well as family members of patients, who have a palpable varicocele about the long-term risks for impaired fertility. Currently, no one can predict with absolute certainty if any adolescent with a varicocele will be at risk for future infertility. Based on existing data, however, it is not reasonable simply to ignore the potential for such a problem until infertility becomes an issue because by that time the chance for reversibility may be lost. It is important to present a balanced discussion because the majority of men with a varicocele will be fertile, and no one is suggesting that all men with a varicocele undergo surgical treatment. Current recommendations for repair are based on the findings of impaired testicular growth and/or spermatogenesis. With early evaluation and selective treatment, however, we should be able to reduce the potential for future fertility problems significantly in adolescents with a varicocele.

Adolescent varicocele

The evaluation and management of adolescents with varicoceles continue to evolve. Current recommendations for repair are based on the findings of impaired testicular growth or spermatogenesis; however, with early evaluation and selective treatment, clinicians should be able to reduce the potential for future fertility problems significantly in adolescents with varicoceles.

The pathophysiology of varicocele-associated male infertility

Varicocele is the most commonly identifiable, surgically correctable lesion associated with male-factor infertility. Surgical correction of a varicocele, whether unilateral or bilateral, results in improvement not only in semen parameters but also in spontaneous and assisted pregnancy rates. Varicoceles seem to induce a number of changes in the testicular microenvironment. These alterations in temperature, hemodynamics, and reactive oxidative species and antioxidant concentrations have been demonstrated to produce deleterious effects on spermatogenesis. However, despite current knowledge in the pathophysiology of varicocele-associated male infertility, the exact mechanism--or mechanisms--by which varicoceles impair fertility remains elusive. This review examines scientific evidence regarding the pathophysiology of varicocele-associated male infertility.

The effects of experimental varicocele on testicular histology and fertility in monorchic adult rats

OBJECTIVE

To determine the effects of a left-sided experimental varicocele on testicular morphology and fertility in right hemicastrated adult rats.

MATERIALS AND METHODS

A double-controlled experimental study was carried out using mature Sprague-Dawley rats, with 12 rats in each treated group and five corresponding controls. Group 1 underwent right orchidectomy, group 2 right orchidectomy and a left varicocele, and group 3 only a left varicocele; each control group underwent a corresponding sham operation. Two months after surgery each rat was placed with two mature female rats for one month to assess fertility. All the rats were then killed and their testes weighed; the mean testicular weight was calculated for each group and the mean seminiferous tubule diameter (STD) measured. Johnsen scores and histological abnormalities were evaluated for each testis using light microscopy.

RESULTS

The mean (SEM) testicular weight and STD in group 2 were significantly lower, at 1311 (100) mg and 225 (11) microm, respectively, than in group 1, at 1771 (28) mg and 255 (4) microm (P<0.05). The mean weights of both testes in rats in group 3 were significantly lower than those in group 1 (P<0.05) and although both mean STDs were less than in group 1, the differences were not significant (P>0.05). There were no differences between the Johnsen scores in groups 2 and 3. There were severe histological abnormalities in the left testes in three of nine and two of eight animals in group 2 and 3, respectively; in group 3, changes in the right testis were detected in one rat. Six of nine and seven of eight rats were fertile in group 2 and 3, respectively.

CONCLUSION

Experimental left varicocele decreased the left testicular weight and STD in both hemicastrated and intact adult rats. However, the presence of the right testis is important for preserving fertility.

Varicocele scintigraphy: a simplified screening method for the detection of spermatic vein reflux

Forty-three men underwent varicocele scintigraphy to exclude underlying varicocele as a possible cause of decreased semen quality. The total acquisition time for each study amounted to as little as 200 seconds. In four cases retrograde blood flow was seen in the left internal spermatic vein, with subsequent clear visualization of the pampiniform plexus. In three of four of these patients, pregnancy ensued after therapeutic intervention. Seven patients showed only increased scrotal activity locally, in the absence of retrograde blood flow. The remaining 32 patients showed a normal blood flow pattern. The existence of spermatic vein reflux in varicocele-related infertility is thought to be a major factor in proper patient selection for therapeutic ligation or embolization of the internal spermatic vein. It is suggested that this simplified scintigraphic method may be useful in the detection of retrograde blood flow in patients with varicocele, especially in small or subclinical varicocele.

Defective mitochondrial oxidative phosphorylation in varicocele-bearing testicles

OBJECTIVES

Our previous study revealed a decreased blood flow in varicocele-bearing testicles. For further understanding of the possible mechanism of varicocele-induced infertility, we investigated the changes in energy metabolism in varicocele-bearing testicles.

METHODS

Partial ligation of the left renal vein was performed in 40 Wistar rats to induce dilation of the internal spermatic vein, and sham operations were performed in 20 other age-matched Wistar rats serving as controls. Orchiectomy was done at 1, 2, 4, and 6 months after induction of varicocele (or sham operation) in both groups. The histologic changes in the testicles were evaluated under the light microscope. The concentration of adenine nucleotides was determined by high-performance liquid chromatography, and various enzyme activities of mitochondria were determined by a spectrophotometer.

RESULTS

Histologic studies of varicocele-bearing testicles showed a lower Johnsen score (8.5 +/- 0.7 versus 9.3 +/- 0.5) and a decreased mean testicular tubular diameter (280.0 +/- 3.2 versus 295.0 +/- 1.4 microns) compared with the testicles in the sham-operated group. The energy charge decreased from 0.71 +/- 0.04, 0.70 +/- 0.03, 0.69 +/- 0.06, and 0.64 +/- 0.03 to 0.62 +/- 0.08, 0.59 +/- 0.05, 0.58 +/- 0.05, and 0.56 +/- 0.02 at 1, 2, 4, and 6 months, respectively. The reduced nicotinamide-adenine dinucleotide-cytochrome c reductase activities were decreased from 136.6 +/- 4.9, 127.3 +/- 10.7, 121.6 +/- 7.8, and 118.9 +/- 8.5 to 96.3 +/- 13.9, 95.6 +/- 27.8, 88.3 +/- 13.8, and 80.4 +/- 8.7 nmol/min/mg of protein, respectively; the succinate-cytochrome c reductase activities were decreased from 50.4 +/- 2.7, 49.0 +/- 4.7, 49.6 +/- 7.1, and 42.6 +/- 1.6 to 40.3 +/- 7.3, 41.0 +/- 11.5, 40.2 +/- 5.7, and 32.0 +/- 1.3 nmol/min/mg of protein, respectively; and the cytochrome c oxidase activities were decreased from 361.2 +/- 23.4, 350.3 +/- 25.5, 223.5 +/- 12.9, and 194.1 +/- 18.3 to 253.7 +/- 32.9, 256.4 +/- 38.8, 178.2 +/- 15.7, and 147.1 +/- 17.2 nmol/min/mg of protein at 1, 2, 4, and 6 months, respectively.

CONCLUSIONS

We thus suggest that defective energy metabolism plays an important role in the impairment of spermatogenesis of varicocele-bearing testicles.

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

OBJECTIVE

To determine the effect of experimental left varicocele on the anatomy of the veins serving the rat testis and to compare that anatomy to known patterns of vascular drainage from the human testis with and without varicocele.

DESIGN

Vascular maps were made of the effluent vessels from the rat testis in control animals and those with a 30-day experimental left varicocele. Consensus maps were arrived at and these were compared to published reports of the pertinent venous anatomy in humans with and without varicocele.

SETTING

Research laboratory.

RESULTS

The major route of blood leaving the rat testis was confirmed to be the spermatic vein, but nine common collaterals were also found to exist. Four of these collaterals became more pronounced with experimental varicocele as did several dilated perineal veins. These latter vessels all led to the iliac vein. The vasculature of the rat experimental varicocele model shares some important anatomical features with human varicocele anatomy.

CONCLUSIONS

Varicocele in humans and in the rat model causes a redistribution of blood flow from a route primarily out the spermatic vein to routes leading to the iliac vein. The redistribution is similar but not identical.

Varicocele related testicular atrophy and its predictive effect upon fertility

Varicoceles are the most common reversible cause of male factor infertility, yet approximately 80% of men with varicoceles are fertile. Therefore, it is unclear whether all adolescents should undergo prophylactic varicocelectomy to prevent future infertility or whether a subgroup of patients who are at increased risk for future infertility can be identified and treated. Testicular size discrepancy or hypotrophy of the testis associated with a unilateral varicocele has been suggested as an indication for prophylactic varicocelectomy in adolescents. We examined 946 men attending a urological clinic for complaints other than infertility to determine whether testis size discrepancy was predictive of infertility in men with left varicoceles. A left varicocele was detected on physical examination in 211 men, of whom 173 (82%) had been able to father children and 38 (18%) had never fathered children. A group of 630 men without palpable varicoceles served as controls, including 528 (84%) with a history of fertility. Testicular size was measured using an orchidometer and the average testicular volume difference was obtained by subtracting left from right testicular volume. The mean testicular volume difference for the fertile men without varicoceles (1.6 +/- 0.3 ml.) was significantly lower than the fertile men with varicoceles (3.1 +/- 0.4 ml.) (p < 0.05) and infertile men with varicoceles (2.5 +/- 0.6 ml.) (p < 0.05). There was no significant difference between fertile and infertile men with varicoceles. This study confirms prior reports that the majority of men with left varicoceles are able to father children and that varicoceles cause significant ipsilateral testicular atrophy/hypotrophy. However, we were unable to demonstrate a correlation between loss of testicular volume and fertility status in men with left varicoceles. Further study is needed to identify the clinical parameters predictive of future infertility in adolescents with varicoceles.

The influence of varicocele on parameters of fertility in a large group of men presenting to infertility clinics. World Health Organization

OBJECTIVE

To assess the role of varicocele in male infertility.

DESIGN

Data analysis of a large population of couples who were systematically investigated for infertility.

SETTINGS

Couples were recruited in 34 World Health Organization collaborating centers in 24 countries.

PATIENTS

Nine thousand thirty-four men presenting as partner of infertile couples.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Physical findings, semen characteristics, coincidental pathology, and spontaneous pregnancies.

RESULTS

Varicocele was found in 25.4% of men with abnormal semen, compared with 11.7% of men with normal semen. It was accompanied by decreased testicular volume, impaired sperm quality, and decline of Leydig cell secretion. Spontaneous pregnancies were as frequent in couples in whom the men did or did not have varicocele.

CONCLUSION

Varicocele is clearly associated with impairment of testicular function and infertility.

Acidification of testicular and epididymal fluids in the rat after surgically-induced varicocele

Experimental left varicocele (ELV) in adult rats produces a bilateral increase in testicular blood-flow and temperature which may alter the intraluminal environment in which sperm mature. The purpose of the present study was to evaluate the effect of ELV on the in-situ pH, PCO2 and bicarbonate concentration ([HCO3-]) in seminiferous tubules (ST), initial segment (IS), proximal caput (PCP), middle caput (MCP), middle corpus (MCR), and proximal cauda epididymidis (PCD) of the rat employing pH and PCO2 microelectrodes. Adult male rats with ELV or sham-surgeries (control) were studied after 30 days. Relative to controls, ELV significantly reduced the in-situ PCO2 in the testicular artery, ST, IS, PCP, MCP, MCR and PCD. In spite of this reduction, all values remained significantly higher than the systemic arterial blood PCO2. Values for in-situ pH in ST, IS, PCP, MCP, MCR, and PCD of control rats were significantly more acidic than systemic arterial blood. Furthermore, ELV decreased the pH in ST, IS, PCP, and MCP when compared to control values. The calculated [HCO3-] in ST from control animals was less than half that in systemic arterial blood and was reduced further in IS, PCP, and MCP. Varicocele did not change the [HCO3-] in systemic arterial blood but reduced markedly the values in ST, IS, PCP, and MCP. These alterations in the in-situ pH, PCO2, and [HCO3-] in structures of the rat testis and epididymis may play a role in the anti-spermatic effect of ELV.

Surgical repair of secondary right varicocele in rats with primary left varicocele: effects on fertility, testicular temperature, spermatogenesis, and sperm maturation

To evaluate whether or not dilation of the right testicular vein is a constant finding in animals with left varicocele and to illustrate its contribution to the detrimental effect of a left varicocele on the right testis, an experimental varicocele model was produced in 40 rats. Ten other rats had a sham operation (group A). Seven weeks after the operation, all 50 rats underwent laparotomy and dilation of both testicular veins was seen in 23 rats, which were randomly assigned to group B (n = 11) and group C (n = 12). One week later, groups A and C underwent sham ligation of the right testicular vein, whereas group B rats underwent resection of this vein. At 84 days after the initial operation, group C rats showed a significant reduction in right epididymal sperm content, motility, and fertilizing capacity, right testicular weight, and right testicular vs. intraabdominal temperature difference when compared with groups A and B. Since surgical repair of the secondary right varicocele improved all the parameters indicating the harmful consequences of the primary left varicocele on the right testis, it appears that dilation of the right testicular vein contributes to the detrimental effect of a left varicocele on the right testis.

Total ligation of the left renal vein in the dog: an inappropriate model for varicocele

Induction of varicocele was attempted by ligation of the left renal vein (LRV) in male dogs (Group I). Before the operation and in the 4-month post-operative period, sperm count, sperm motility, and sperm morphology of Group I (n = 8) dogs were compared to sham operated animals (Group II, n = 5). Furthermore, haemodynamics as well as testicular and vascular morphology were studied. In Group I, changes in diameter and consistency of the spermatic cord were temporary. Semen quality was reduced significantly during the second month after ligation of the LRV, but improved thereafter. Haemodynamic studies revealed that LRV blood pressure was increased significantly in Group I dogs. An extensive venous collateral network replaced the occluded LRV. Retrograde blood flow in the left testicular vein (LTV) was observed only in the proximal part of the LTV of Group I dogs. In Group II dogs numerous pairs of sufficient valves prevented reflux into the LTV. Histological examination revealed that spermatogenesis was not impaired and that the left pampiniform plexus had not changed. The number of Leydig cells was decreased slightly in Group I dogs. Sufficient valves in the LTV prevented formation of a permanent varicocele.

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

With no consistent animal prototype for the study of varicocele, we set out to create a model in the rat by complete ligation of the main branch of left spermatic vein (MBSV) or by partial ligation of the left renal vein. Three months later, the histology, ultrastructure and temperature of the testis and epididymis were studied. Microscopically, spermatogenic arrest was the most frequent anomaly seen. The most frequently noted ultrastructural change of the testis was distension of smooth endoplasmic reticula in Sertoli cells. The microvilli of columnar epithelia in epididymis were sparse and showed local defects. Lesions and increased temperatures in the testis and epididymis induced by the ligation of the left MBSV were similar to those seen in partial ligation of the left renal veins, with no significant differences between left and right. Significant differences were found, however, on comparison with the controls.

The significance of elevated scrotal temperature in an adolescent with a varicocele

Simultaneous measurements of left and right scrotal, and axillary skin temperatures were recorded in 58 consecutive adolescents (mean age 14.4 years) with a grade II-III left sided varicocele, and nine control adolescents without genital pathology (mean age 15.7 years). Left and right testicular volumes were determined in both groups. The adolescents with a varicocele had a significant bilateral elevation of the scrotal temperatures compared to the control subjects. This relative hyperthermia was present in both supine and standing positions. The mean left scrotal temperature of varicocele patients was significantly higher in the standing position than in the supine position, which may reflect the dependent venous filling of the varicocele. Those varicocele patients who maintained a left scrotal temperature at least 1.4 degrees C cooler than axillary did not have significant left testicular volume loss, whereas those whose left temperature was approximately equal to axillary did have significant growth retardation of the left testis. Following successful varicocele surgery, left scrotal temperatures were significantly cooler, and statistically indistinguishable from controls. The left testicular volumes were also significantly improved with respect to corresponding right testicular volumes. These observations suggest that adolescents with a moderate to large left varicocele have a significant bilateral loss of testicular thermoregulation. In those individuals with a significantly warmer left hemiscrotum, there is a definite increased potential for left testicular volume loss. Varicocele surgery can reverse this process.

The effect of experimental varicocele on the testis of adolescent rats

Experimental varicocele was created by partial ligation of the left renal vein in rats 4, 7 and 12 weeks old to compare the effects of varicocele on the testis at different times of onset: prepuberty, adolescence and adulthood. We examined the testes at 4 and 8 weeks after creation of the varicocele. The experimental groups of rats 4 and 12 weeks old showed slight testicular changes compared to control groups at 4 and 8 weeks postoperatively. In the 7-week group left testicular weight was significantly decreased (1.03 +/- 0.31 gm.) compared to that of the control group (1.51 +/- 0.12 gm.) at 4 weeks. The seminiferous tubular diameter in the left testis also was significantly reduced (219 +/- 37 microns) compared to that of the control group (270 +/- 14 microns). Histological changes, such as degeneration of germinal epithelium, tubular atrophy, Sertoli cell hyperplasia and interstitial edema, were observed more frequently in the 7-week group. At 8 weeks these changes were less significant. Our results suggest that varicocele during adolescence has the most damaging effects on the testis in rats.

Effects of experimental varicocele require neither adrenal contribution nor venous reflux

Experimental left varicocele (ELV) is known to induce bilateral changes in the rat testis that, where comparisons are possible, are similar to the changes induced by unilateral varicocele in the human. In the present study, we have determined whether or not left adrenal products are important to the changes induced by ELV and whether or not reflux of left renal vein content occurs in the ELV rat. In the first study, testicular blood flow and temperature were studied in control animals and those with ELV, left adrenalectomy (LAX), or ELV + LAX. Control left and right testicular blood flow (33.6 +/- 0.8 and 33.6 +/- 1.5 ml./min./100 gm. tissue respectively) was significantly elevated by ELV (to 39.9 +/- 0.9 and 41.2 +/- 2.7 ml./min./100 gm. tissue, respectively) and the difference between abdominal and testicular temperatures (delta T) was significantly reduced. Control delta T's for right and left testes were 3.2 +/- 0.2C and 3.2 +/- 0.2C, respectively, and right and left delta T's for ELV animals were 2.0 +/- 0.3 degrees C and 2.0 +/- 0.3C, respectively. These blood flow and temperature changes also occurred when ELV animals were subjected to simultaneous LAX. Additionally, when 85Sr-labelled microspheres were infused into the left renal vein, they did not appear in either left or right testes of ELV animals. We conclude that there is no evidence for reflux down the spermatic vein in ELV in rats and adrenal products do not reach the testis via this route after being secreted into the renal vein. We raise the suggestion that the same may be true in the human.

Elevation of intratesticular and scrotal skin surface temperature in men with varicocele

A possible mechanism of varicocele-induced infertility is believed to be elevation of testicular temperature. Sensitive needle thermistors were used to measure directly intratesticular and bilateral scrotal surface temperatures simultaneously in anesthetized infertile men with varicocele and control subjects. We found that intratesticular temperature is elevated significantly in humans with varicocele. In addition, we have shown that scrotal skin surface temperature is elevated in men with varicocele. Furthermore, we demonstrate that unilateral varicocele is associated with bilateral elevation of scrotal surface temperature. These findings confirm the results of animal studies revealing elevation of intratesticular temperature associated with varicocele and suggest bilateral elevation in unilateral varicocele.

Adolescent varicocele: objective indications for treatment

We measured the gonadotropin response pattern to the intravenous injection of luteinizing hormone-releasing hormone in 53 male adolescents 11 to 17 years old (average age 14.2 years) with a grade II to III varicocele. Volume loss of the testis ipsilateral to the varicocele of 2 cc or more was noted in 32 patients. Baseline serum levels of follicle-stimulating hormone, luteinizing hormone and testosterone were determined, and measured again at 15, 30 and 60 minutes following intravenous injection of luteinizing hormone-releasing hormone. Of the patients 23 had an exaggerated response pattern following luteinizing hormone-releasing hormone stimulation, including abnormally high post-stimulation levels of luteinizing hormone only in 6, follicle-stimulating hormone only in 4, and follicle-stimulating and luteinizing hormones in 13. No significant difference in mean age, testosterone levels or loss of testicular volume was noted between the abnormal and normal response groups. This study indicates that approximately 45 per cent of adolescents with a varicocele have evidence of testicular injury. The physical examination was of no value in predicting which patient with a varicocele would display evidence of testicular dysfunction. We suggest that the luteinizing hormone-releasing hormone stimulation test become a routine part of the evaluation of an adolescent with a varicocele.

Induction of varicocele in the dog: I. Partial ligation of the left renal vein does not induce a varicocele in the dog

Induction of varicocele was attempted by partial ligation of the left renal vein in 10 male dogs. The effects on sperm count, sperm motility, and sperm morphology, as well as on hemodynamics, were assessed. Furthermore, testicular, vascular, and kidney morphology was studied. Changes in the diameter and consistency of the left spermatic cord were found to be temporary. Total sperm count, sperm motility, and the total number of oval forms were not significantly altered. Hemodynamic studies revealed a renocaval pressure gradient, but retrograde flow in the distal part of the left testicular vein could not be observed by arteriography. A collateral network was found to compensate for the restricted left renal vein. Histologic examination revealed no damage to the seminiferous epithelium. Changes were not found in the kidney and left pampiniform plexus. Although some temporary changes induced by the partial ligation of the left renal vein are suggestive of varicocele, this hemodynamic study shows that the presented dog model does not mimic varicocele as encountered in man.

Biochemical changes in testicular varicocele

The precise mechanism of the hypospermatogenesis associated with varicocele has remained uncertain, although there have been a number of speculations on the etiology of the associated infertility. The altered spermatogenesis has been attributed to the reflux of toxic metabolites from either adrenal or renal origin, disturbed hormone status, spermatic venous hypertension, testicular hypoxia secondary to stasis, and abnormal temperature regulation. However, the biochemical changes of the testicular tissue with varicocele have been only partially explored. This overview includes the available information on the biochemical change in the testes associated with varicocele as well as the introduction of basic biochemical aspects on the testes, which may give new insights into the possible pathophysiological mechanism of male infertility.

Deoxyribonucleic acid polymerase activity in the testes of infertile men with varicocele

Activities of deoxyribonucleic acid (DNA) polymerase alpha, beta, and gamma were measured in extracts of testicular biopsy specimen obtained from 37 cases of male infertility with left varicocele and compared with those of 6 normal controls. It was observed that levels of DNA polymerase alpha, beta, and gamma were significantly lower in infertile men than normal controls on both sides of testes. Among three DNA polymerases, the level of DNA polymerase beta activity well correlated with the histological findings (Johnsen's score), i.e., the extent of differentiation of germinal cells. DNA polymerase beta activity appeared to be the lowest in the patients whose sperm density was less than 5 X 10(6)/ml. On the other hand, no correlation was apparent between levels of DNA polymerases and other clinical parameters, e.g., testicular volume, sperm motility, grade of varicocele, and serum hormone levels. These results suggest that the combined decrease in the DNA polymerase activities may be one of the factors that have deleterious effects on spermatogenesis in varicocele patients.

The clinical varicocele in infertility

Of 238 infertile males seen over a 47-month period, 47 (20%) had a varicocele. Of these 51% had an abnormal sperm count (21% were azoospermic and 30% oligozoospermic) and 60% had less than a third of sperms motile; 23 patients were subjected to gonadotrophin assays. Serum follicle stimulating hormone and leutinising hormone levels were elevated in 48% and 70% of patients respectively. Serum prolactin assayed in 19 patients was raised in 10% and serum testosterone estimated in 16 patients was low in 6%. Twenty-five patients (53%) were advised to undergo surgery but only 10 agreed. Of these, 1 showed a dramatic improvement in his spermiogram and a pregnancy ensued. The sperm count and motility of 2 others improved after treatment with prostaglandin synthetase inhibitors, and 1 after testosterone. Medical treatment improved the count and motility in 7 of 8 patients in whom surgery was not suggested as primary treatment because of abnormal hormonal results. This study has shown that infertile patients with varicocele are a heterogeneous group and that improvement in spermiograms can best be achieved by selective treatment; this may be surgery, surgery followed by medical treatment, or medical treatment alone.

The endocrinology of varicoceles

There is good evidence of an associated abnormality in testicular hormone production and spermatogenesis in some men with varicoceles. This abnormality can be demonstrated with dynamic tests of the hypothalamic-pituitary-testicular axis and by measuring seminal plasma androgen levels. A high proportion of oligozoospermic men who have abnormal hormone profiles will respond favorably to correction of their varicosities. Several oligozoospermic men with varicoceles have normal hormonal profiles. To date, in our unit, none of these men has had an improvement in seminal characteristics after varicocelectomy. This result would suggest that these men have incidental varicoceles. It is not clear what the testicular defect is leading to abnormal spermatogenesis in these men. Clearly, more studies are required in this group of men and in the men with sperm densities greater than 30 X 10(6)/ml, the majority of whom have normal responses to GnRH infusion. More information is needed regarding the intratesticular control of hormone production and spermatogenesis. As our knowledge of the paracrine system within the testis increases, so should our understanding of the mechanisms involved in the association of varicoceles and infertility.

Pathology of varicocele in the ram

A total of 40 mature or aged rams with spontaneous varicocele detected by scrotal palpation were subjected to detailed necropsy examination. Varicocele was bilateral in 22 rams or was located on the left or right sides only, in 8 and 10 rams, respectively. This distribution contrasted with varicocele in man in which the left side is involved in 70 to 100% of cases. Mean sizes of varicoceles in mm (length x diameter) were 117 x 46 and 104 x 45 for the left and right sides, respectively, and they were located high in the pampiniform plexus, approximately 100 mm from the dorsal pole of the corresponding testis. All varicoceles were thrombosed. Changes associated with large varicoceles included testicular mineralisation and occluding thrombosis of testicular vessels. Total testis weight-bodyweight ratio in rams with varicocele (5.8 to 6.4 x 10(-3] was significantly less (P less than 0.05) than in normal (control) rams from the same flocks (7.9 x 10(-3] suggesting that some degree of testicular atrophy resulted from presence of a varicocele.

Decrease of topoisomerase I activity in the testes of infertile men with varicocele

Topoisomerase I, which is involved in DNA metabolism, was measured in the testes of 37 infertile men with varicocele, using a minute amount of testicular biopsy specimen. In 38% of infertile men topoisomerase I activity was lower than that of normal men. Forty-six percent of patients with high grade varicocele (grade III) showed reduced topoisomerase I activity, while only 26% of patients with low grade varicocele (grades I and II) showed reduced levels of topoisomerase I. Johnsen's score of the patients with low topoisomerase I activity was lower than that of patients with normal levels of topoisomerase I. The decrease of topoisomerase I activity may be correlated with at least some fraction of hypospermatogenesis associated with varicocele.

The effects of unilateral, experimental varicocele are not mediated through the ipsilateral testis

Unilateral varicocele has been associated with diminished male fertility in humans and with bilateral physiologic and histologic changes in the testis of humans and laboratory animals. In particular, left varicocele in Sprague-Dawley rats results in bilateral increases in testicular temperature and blood flow. The mechanism by which unilateral varicocele can cause testicular changes is not known. The purpose of the present study was to determine whether or not the presence of either the ipsilateral or contralateral testicle is necessary for these effects of the varicocele to occur in the opposite testis. Varicoceles were created in adult, male rats by partial constriction of the left renal vein. Bilateral testicular blood flow was measured by a radiolabelled microsphere distribution technique and testicular temperature was taken with a needle probe thermometer. Right or left orchiectomies were performed on selected animals at the time of surgery to establish the unilateral left varicocele. Animals were studied 30 days after surgery. Mean testicular blood flow was significantly increased (P less than 0.01) in all animals having a left varicocele when compared with animals not having a varicocele regardless of whether a unilateral orchiectomy was performed. Likewise, the mean difference between intraabdominal temperature and intratesticular temperature (delta T) was significantly decreased in all groups of animals having varicoceles when compared with groups without varicoceles whether or not an orchiectomy had been performed. Thus, the studied bilateral effects of left-sided, experimental varicocele in the rat are not dependent upon the presence of a left testicle.

Testicular hemodynamic changes after the surgical creation of a varicocele in the rat. Intravital microscopic observations

The present study investigated the effect of a surgically induced varicocele on the dynamics of testicular blood flow. The surface vasculature of the normal and the varicocele-affected testis was examined utilizing intravital epi-illumination microscopy. Application of this technique to the study of the varicocele is new. Blood flow characteristics in surface veins were studied as the surface temperature of the testis was varied. Periodic, reproducible stoppages in blood flow, determined by direct observation of the red blood cells, were seen in seven of eight sham animals at the lower temperatures. These stoppages were abolished and blood flow increased at higher temperatures; stoppages reappeared at lower temperatures. The periodic stoppages were present in only one of eight rats with a proven varicocele (P less than 0.025) at any temperature studied. This loss of blood flow regulation may be the result of a loss of testicular arteriolar tone and may explain the increase in testicular blood flow and temperature elevation observed in association with a varicocele. These findings may provide new insights into the pathophysiology of the varicocele and highlight the need to study the microvascular sequelae of this vascular abnormality.

Repair of experimental varicoceles in the rat. Long-term effects on testicular blood flow and temperature and cauda epididymidal sperm concentration and motility

The effects of varicocele and varicocele repair on testicular blood flow, temperature, sperm counts, and sperm motility were assessed in adult male rats. The duration of the experimental varicocele and the varicocele repair were three and two times as long, respectively, as that studied previously. Varicoceles were created by partial ligation of the left renal vein and repairs were accomplished by high ligation of the left spermatic vein. Testicular blood flow was determined by using the radiolabeled microsphere technique. Testicular temperature was taken via needle probe thermometer. Sperm samples were obtained by micropuncture of the cauda epididymidis, and were counted on a hemacytometer and observed for motility under the light microscope. Varicoceles were studied 100 days after their creation. Repairs were performed on varicoceles that had lasted 100 days and the animals were studied 60 days after repair. Mean testicular blood flow (ml/100 g tissue/min) was significantly increased (P less than 0.05) in animals with varicocele (left testis (LT) = 42.2 +/- 1.1, right testis (RT) = 39.1 +/- 1.2) when compared with normal controls (LT = 29.3 +/- 1.6, RT = 29.6 +/- 1.7), animals with varicocele repair (LT = 30.7 +/- 1.3, RT = 30.0 +/- 1.6), or sham-operated animals (LT = 29.7 +/- 1.4, RT = 31.1 +/- 1.4).(ABSTRACT TRUNCATED AT 250 WORDS)

Scrotal temperature reflects intratesticular temperature and is lowered by shaving

Intratesticular and scrotal skin temperatures were measured in 34 men undergoing scrotal or inguinal surgical procedures under general anesthesia. Scrotal temperatures were measured before and after a dry scrotal shave. Intratesticular temperature was measured under direct vision with a needle thermistor. Linear regression analysis revealed a strong correlation between intratesticular and scrotal skin temperatures. In addition, simple scrotal shaving significantly decreased scrotal skin temperature. These observations suggest that scrotal skin temperature measurements may be useful to detect elevations of intratesticular temperature and scrotal shaving may be a useful adjunct for testicular cooling.

Effects of varicocele after unilateral orchiectomy and sympathectomy

An experimental varicocele was created in the adult rat by partial ligation of the left renal vein. There was a significant bilateral elevation of both testicular blood flow and temperature in the varicocele animals (p less than 0.01). Mean testicular blood flow for control and varicocele animals was 29.6 +/- 1.0 and 39.8 +/- 2.0 ml./min./100 gm. tissue, while mean testicular temperature was 34.4 +/- 0.1 and 35.3 +/- 0.2C, respectively. A left orchiectomy was combined with a left varicocele to determine if the left testis is essential for the right testicular response to a varicocele. Elevation of right testicular blood flow was not altered by left orchiectomy (p less than 0.05); however, right testicular temperature was no longer significantly increased. Mean right testicular blood flow and temperature for this group was 39.0 +/- 1.5 ml./min./100 gm. tissue and 34.2 +/- 0.15C, respectively. A left sympathectomy was combined with a left varicocele to ascertain if the right testicular response to the left varicocele was mediated through a neural pathway. A significant bilateral increase in testicular blood flow was noted with a left sympathectomy alone, and thereby masked the ability to evaluate the right testicular response to the simultaneous left sympathectomy and varicocele. Elevation of right testicular blood flow in response to the left varicocele is independent of the presence of a left testis and any immune response it may stimulate. The role of the sympathetic nervous system as a mediator of the bilateral varicocele effect remains undetermined.

Varicocele: temporal considerations

The pathophysiology of the abnormal spermatogenesis seen in the presence of the varicocele has not been elucidated in spite of extensive study. Furthermore, no satisfactory explanation exists for the bilateral abnormal spermatogenesis seen in a process which is felt to be unilateral in the majority of cases. The present study was designed to determine if a surgically produced unilateral varicocele would lead to ipsilateral testicular changes prior to the onset of contralateral testicular alterations. Utilizing the rat model and microsurgical techniques, the effects of the varicocele on ipsilateral and contralateral spermatogenesis was studied at intervals over 49 days. Mean seminiferous tubular diameter measurements and flow cytometric analysis of testicular tissue were utilized to assess spermatogenesis. A statistically significant decrease in mean seminiferous tubular diameter was seen between day 1 and day 49 in the left testicle. The right testicle tended to demonstrate similar changes but these were not significant by the method of analysis used. Flow cytometric analysis of testis DNA content also revealed a statistically significant difference in the percentage of haploid, diploid and tetraploid cells in the left testis on day 1 as compared to day 49. The right testis again tended to demonstrate similar but not significant changes. Though primarily a unilateral process, bilateral spermatic vein abnormalities were also visualized in some animals. This observation may contribute to the bilateral effect observed. These studies demonstrate that a surgically created left varicocele will result in bilateral testicular alterations. Within the time frame of the study, the ipsilateral alterations progressed to a greater degree.

Varicocele: reversal of the testicular blood flow and temperature effects by varicocele repair

An experimental left varicocele was created in the adult rat by partial ligation of the left renal vein. A varicocele repair was performed by high ligation of the internal spermatic vein. Testicular blood flow and temperature changes were measured in control and sham animals, animals 30 days after establishment of varicocele and animals 30 days after varicocele repair. There was a statistically significant (p less than or equal to 0.01) bilateral elevation of testicular blood flow and temperature in the varicocele group compared to control and sham groups. Varicocele repair returned these blood flow and temperature values to normal. Average testicular blood flow for control, varicocele, sham varicocele and varicocele repair animals were 29.6 +/- 1, 39.8 +/- 2, 30.7 +/- 1 and 29.8 +/- 1 ml. per min. per 100 gm. tissue, respectively. Testicular temperatures averaged 34.4 +/- 0.1, 35.3 +/- 0.2, 34.4 +/- 0.1 and 34.5 +/- 0.1 degrees C, respectively. It is possible that the elevation in blood flow is associated with the elevation of intratesticular temperature, which is known to impair spermatogenesis. The data support a relationship between the varicocele and potential testicular damage.