The Effects of Unilateral, Experimental Varicocele Are Not Mediated Through the Ipsilateral Testis

Abstract

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.

Decreased Blood Flow and Defective Energy Metabolism in the Varicocele-Bearing Testicles of Rats

“…Green et al [9] used radioactive microsphere tracer to detect testicular blood flow and found that it was significantly higher in varicocele-bearing rats than in the controls (39.8 ± 2.5 versus 29.4 ± 1.0 ml/min/100 g). Hurt et al [16] obtained the same results (40.1 ± 3.2 ver-bular or peritubular capillaries. The data were recorded after the signal becoming stable, and multiple measure ments were made to prevent non-uniform distribution of the blood flow.…”

“…We found that the blood flow to the testicle decreased significantly after establishing a varicocele in rats, and no apparent changes were found in the shamoperated group. The likely explanation for this disparity is that Green et al [9] and Hurt et al [16] measured total blood flow by counting the radioactivity of the testicle in vitro. However, we measured the regional capillary blood flow by laser Doppler flowmeter, and Harrison et al [ 17] measured total blood flow by the clearance rate of 133Xe in vivo.…”

Is Ipsilateral Testis Mandatory for the Occurrence of Contralateral Intratesticular Biochemical Changes Indicative of Hypoxia after Unilateral Spermatic Cord Torsion?

“…It is evident form the present study and of other studies on varicocele [5][6][7] that ipsilateral testis does not produce a substance which would trigger the aforementioned path ways in inducing changes in the contralateral testes. Phys ical distention of the ipsilateral spermatic vein has been speculated to be the triggering mechanism behind the con tralateral testicular response to unilateral varicocele [12], Similarly, torted spermatic vessels during unilateral sper matic cord torsion might transmit a signal to the contra lateral nontorted blood supply either Immorally or neurally.…”

“…Then comes the question whether the presence of ipsilateral tes ticular tissue is required for the transmission of this stimu lus. Studies with experimental varicocele have shown that unilateral varicocele created in the absence of ipsilateral testis also causes increase in contralateral testicular blood flow; thus it has been concluded that the presence of ipsi lateral testicular tissue is not mandatory for the contralat eral blood flow changes after unilateral varicocele [5][6][7].…”

Histomorphological Differences of Spermatic Cords regarding Subinguinal versus Inguinal Levels: A Cadaveric Study

“…A significant improvement in the parameters indicating harmful effects of the varicocele on the testicles is shown after surgical repair of experimental varicoceles in rabbits [1] . There are experimental studies focusing on the effects of unilateral varicocele with bilateral physiologic and histologic changes in both testicles as well as others aiming to analyze the effects of retrograde adrenal metabolites flow on testicular damage [2,3] . Varicocelectomy stops any further damage to testicular function and results in seminal improvement and natural pregnancy in 60-80% and 20-60% of couples, respectively [4] .…”