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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.

PURPOSE: A rat varicocele model using partial occlusion of the left renal vein was described previously. Reproducibility in creating this model has met with varied success. Alternate routes of testicular venous drainage may negate the effect of partial renal vein occlusion on varicocele creation. We hypothesized that varicocele induction would be more effective if microsurgical ligation of the gonadal venous drainage to the common iliac vein was combined with partial occlusion of the left renal vein. MATERIALS AND METHODS: We randomly assigned a total of 36 rats to 3 groups, including sham surgery, partial renal vein occlusion alone (the classic technique) and microsurgical ligation. Half of the rats in each group were evaluated at 5 and 12 weeks, respectively. We evaluated internal gonadal vein and spermatic cord diameter, testicular weight, cauda epididymal sperm concentration and motility and testicular histology using the Johnsen score as well as serum and intratesticular testosterone and dihydrotestosterone. RESULTS: Five weeks after varicocele creation the microsurgical ligation group had a larger spermatic cord diameter and lower Johnsen scores than rats in the classic technique and sham surgery groups. At 12 weeks the microsurgical ligation group had a larger spermatic cord diameter, lower cauda epididymal sperm concentration, lower sperm motility and worse histology than the classic technique and sham surgery groups. There was no difference in serum androgen outcomes but the microsurgical ligation group had lower intratesticular androgens. CONCLUSIONS: Adding microsurgical ligation of testicular vein collaterals in the pelvis to partial renal vein occlusion appears to improve the effectiveness of creating a rat varicocele model.