Immunohistopathology of the contralateral testis of rats undergoing experimental torsion of the spermatic cord

Aim:To evaluate the immunohistopathological changes in the contralateral testis of rats after an experimental sper-matic cord torsion.Methods:Male Sprague-Dawley rats of 45-50 days old were subjected to a 720° unilateralspermatic cord torsion for 10,30 and 80 days(experimental group,E),respectively or sham operation(controlgroup,C).Histopathology of the contralateral testis as well as germ cell apoptosis were studied using the TerminalDeoxynucleotidyl Transferase Biotin-dUTP Nick End Labeling(TUNEL)technique.The number of testicularlymphocytes,mast cells and macrophages,and the expression of tumor necrosis factor-α(TNF-α)and its receptor(TNFR1)in testicular cells of the contralateral testis were quantified by histochemistry and immunohistochemistry.TNF-α concentration in testicular fluid was determined by ELISA.Results:In the contralateral testis of rats fromthe E group,the maximal degree of damage of the germinal epithelium was seen 30 days after torsion.At this time weobserved in the E group vs.the C group increases:(i)the number of testicular T-lymphocytes;(ii)the number oftesticular mast cells and macrophages;(iii)the percentage of macrophages expressing TNF-α:(iv)TNF-α concen-tration in testicular fluid;(v)the number of apoptotic germ cells;and(vi)the number of TNFR1~ germ cells.Conclusion:Experimental spermatic cord torsion induces,in the contralateral testis,a focal damage of seminiferous tubulescharacterized by apoptosis and sloughing of germ cells.Results suggest humoral and cellular immune mediatedtesticular cell damage in which macrophages and mast cells seem to be involved in the induction of germ cell apoptosisthrough the TNF-α/TNFR1 system and in the modulation of the inflammatory process.(Asian J Andro12006 Sep;8:576-583)     

大鼠一侧睾丸扭转对侧睾丸改变的实验研究

目的 :研究一侧睾丸扭转 (UTT)后对侧睾丸组织学及生精细胞凋亡的改变 ,以明确UTT后对侧睾丸是否存在损伤。　方法 :SD雄性大鼠 6 0只 ,随机分为实验组 (n =4 8)及对照组 (n =12 )。实验组采用Turner方法建立左侧睾丸扭转模型 ,于扭转后 6h处死 4只 ,其余 4 4只再分为扭转睾丸复位及切除组 ,分别于术后 1d、1周、4周处死7～ 8只 ,取睾丸组织进行组织学及生精细胞凋亡的检测。　结果 :UTT复位后对侧睾丸组织学发生明显改变 ,生精细胞凋亡指数明显高于对照组 (P <0 .0 5 )。扭转睾丸切除后对侧睾丸变化不明显。　结论 :UTT可引起对侧睾丸损伤 ,其机制可能与再灌注有关 ,扭转睾丸切除可防止或减轻对侧睾丸的损伤     

Protective role of erythropoietin during testicular torsion of the rats

Testicular torsion is an important clinical urgency. Similar mechanisms occurred after detorsion of the affected testis as in the ischemia reperfusion (I/R) damage. This study was designed to investigate the effects of erythropoietin (EPO) treatment after unilateral testicular torsion. Fifty male Sprague-Dawley rats were divided into five groups. Group 1 underwent a sham operation of the right testis under general anesthesia. Group 2 was same as sham, and EPO (3,000 IU/kg) infused i.p., group 3 underwent a similar operation but the right testis was rotated 720° clockwise for 1 h, maintained by fixing the testis to the scrotum, and saline infused during the procedure. Group 4 underwent similar torsion but EPO was infused half an hour before the detorsion procedure, and in group 5, EPO was infused after detorsion procedure. Four hours after detorsion, ipsilateral and contralateral testes were taken out for evaluation. Treatment with EPO improved testicular structures in the ipsilateral testis but improvement was less in the contralateral testis histologically, but EPO treatment decreased germ cell apoptosis in both testes following testicular IR. TNF-α, IL-1β, IL-6 and nitrite levels decreased after EPO treatment especially in the ipsilateral testis. We conclude that testicular I/R causes an increase in germ cell apoptosis both in the ipsilateral and contralateral testes. Eryhropoietin has antiapoptotic and anti-inflammatory effects following testicular torsion.     

Histological and immunohistochemical studies on the damage of contralateral testis following the unilateral testicular torsion in Wistar rats

The effect of experimental unilateral torsion of the testis on the contralateral intrascrotal testis in Wistar rats was evaluated histologically and immunohistochemically. The results were summarized as follows. 1) Histological damage of the seminiferous tubules in the contralateral testis was present only in adult rats. 2) The histological change 3-5 weeks after the experimental torsion consisted of marked decrease of spermatocytes, loss of spermatids and spermatozoa and numerous Sertoli-cell only tubules. Hyperplasia of the interstitial cells was demonstrated without thickness of the basement membrane and infiltration of the inflammatory cells. The tubular diameter and the ratio of contralateral testicular weight to rat body weight were significantly decreased (p less than 0.05) in torsion group. 3) Using an indirect immunofluorescent method, the positive immunohistochemical staining on spermatid and spermatozoa of normal testicular tissue was demonstrated using only the serum of rat with histological damage on the contralateral testis. Therefore, the phenomenon may be ascribable to the presence of antisperm antibody. It is concluded that the mechanism of the damage in seminiferous tubules of the contralateral testis with experimental torsion in adult Wistar rats is related to the humoral immunity producing antisperm antibody.     

Capsaicin effectively prevents apoptosis in the contralateral testis after ipsilateral testicular torsion

OBJECTIVE: To evaluate the effect of afferent nerve blockage by administration of capsaicin on apoptotic changes in the contralateral testis in rats undergoing ipsilateral testicular torsion. MATERIALS AND METHODS: Twenty male albino rats were randomly divided into four groups. In groups 1 and 2, rats underwent a sham operation and testicular torsion, respectively, after the intraperitoneal administration of 0.9% NaCl. Similarly, in groups 3 and 4 the rats underwent a sham operation and testicular torsion, respectively, after an intraperitoneal capsaicin injection. The testes were untwisted 24 h later and the contralateral testes harvested. Apoptosis was assessed in paraffin-embedded sections stained for nuclear DNA fragmentation. Fifteen cells were counted in each seminiferous tubule and the apoptotic cells recorded. A score was calculated for each group and the results compared using the Kruskal-Wallis analysis of variance and Mann Whitney U-tests, with P<0.05 considered to be significant. RESULTS: The mean apoptotic score of group 2 was significantly higher than that of the other groups. There was no difference between the apoptotic scores of groups 1 and 3, 1 and 4, and 3 and 4. CONCLUSION: Capsaicin effectively prevented apoptosis in the contralateral testes of rats that had undergone testicular torsion.     

低温联合地塞米松对大鼠睾丸扭转复位后eNOS表达及生精细胞凋亡的影响

目的:探讨低温联合地塞米松对睾丸扭转复位后的保护作用,以及对eNOS表达及生精细胞凋亡的影响。方法:将80只青春期SD大鼠随机分为4组,每组20只。4组大鼠分别扭转左侧睾丸720°2 h,建立单侧睾丸扭转模型,随后各组做如下处理,A组:常温+生理盐水、B组:低温+生理盐水、C组:低温+地塞米松、D组:常温+地塞米松;术后48 h采集睾丸,通过HE染色光镜观察睾丸组织病理学改变、免疫组化法检测eNOS表达、TUNEL法检测睾丸生精细胞凋亡。结果:HE染色光镜下见4组大鼠扭转侧睾丸组织均有不同程度损伤,其中A组睾丸损伤最明显,其余3组扭转侧睾丸得到不同程度保护;睾丸组织eNOS免疫组化检测结果:A组扭转侧(左侧)睾丸组织阳性细胞数及阳性细胞着色强度明显强于B、C、D 3组,差异具有显著性(P<0.05、P<0.01、P<0.01);凋亡细胞染色:细胞核呈深棕黄色或棕褐色,A组扭转侧(左侧)睾丸可见大量生精细胞凋亡,凋亡指数AI(31.12±4.68)明显高于B组(16.58±6.22)(P<0.05)及C(8.60±1.15)、D组(13.52±3.06)(P<0.01)。结论:睾丸扭转复位后的缺血再灌注损伤可导致生精细胞凋亡增加、睾丸生殖能力下降;应用低温联合地塞米松能显著增强睾丸组织的抗损伤能力,较好地保护了扭转复位后睾丸的生精功能。     

单侧睾丸扭转对生殖细胞凋亡及黄芪保护作用的实验研究

目的观察大鼠单侧睾丸扭转／复位后患侧和对侧睾丸生精细胞凋亡情况,探讨单侧睾丸扭转／复位后生殖能力下降的机制以及黄芪注射液对其再灌注损伤的保护作用。方法将40只健康雄性Wistar大鼠分为4组,分别为假手术对照组（A组）,睾丸扭转／复位组（B组）,睾丸扭转／复位＋单次腹腔内注射黄芪注射液组（C组）及扭转／复位十连续腹腔内注射黄芪注射液组（D组）,每组10只。按Turner法建立睾丸扭转／复位模型,所有大鼠均在同等条件下喂养至术后7d处死,切取双侧睾丸后检测凋亡指数。结果扭转侧睾丸生殖细胞凋亡指数（AI）A组（5．82±1．21）与B组（36．18±8．40）、C组（20．39±3．57）、D组（11．61±5．12）相比差异有显著性（P〈0．05）,B组明显高于C组及D组（P〈0．05）,C组与D组相比差异有显著性（P〈0．05）;B组对侧睾丸（12．95±3．06）与C组（9．45±1．71）、D组（7．56±1．06）两组对侧睾丸AI相比差异有显著性（P〈0．05）,C、D两组对侧睾丸AI差异有显著性（P〈0．05）。结论单侧睾丸扭转可致患侧和对侧睾丸生精细胞凋亡明显增加,黄芪注射液可明显减少双侧睾丸生殖细胞凋亡,连续应用黄芪注射液优于单次应用。     

Activation of endothelial nitric oxide synthase in contralateral testis during unilateral testicular torsion in rats

There are controversies about the injury of the contralateral testis during unilateral testicular torsion (UTT). An autonomic reflex arc between bilateral testes has been proposed. The authors focused on the involvement of nitric oxide (NO) in the contralateral testis during UTT. Eight-week-old male Wistar rats underwent unilateral torsion (1 h)-detorsion (up to 24 h). NO synthase (NOS) activity was detected as NADPH-diaphorase activity after fixation by paraformaldehyde. N-nitro-L-Arginine methyl ester (L-NAME, 20 mg/kg) was injected intravenously to the other group of rats. To evaluate the testicular injury, proteolysis of alpha-fodrin production was detected by Western blotting. Apoptosis of the germ cells was evaluated by TUNEL. Long-term effect on spermatogenesis was evaluated by flow cytometry at 60 days after UTT. Transient activation of NOS was detected following the proteolysis of alpha-fodrin in the contralateral testis. L-NAME inhibited these alterations. NADPH-diaphorase activity and eNOS immunoreactivity were co-localized in the endothelial cells. These reactions were not observed in other organs. There was neither enhanced apoptosis nor deteriorated spermatogenesis in the contralateral testis during and 60 days after UTT. In the contralateral testis, eNOS-derived NO regulates the vasomotor function against unilateral testicular torsion, whereas it acts slightly cytotoxic. These results suggest the possible involvement of a testis-specific neurovasomotor reflex between the bilateral testes.     

Blood perfusion of the contralateral testis evaluated with contrast-enhanced ultrasound in rabbits with unilateral testicular torsion

The changes of blood perfusion of contralateral testis after unilateral testicular torsion remain controversial. In this study, 28 New Zealand white male rabbits were randomly divided into five groups. Group A (n = 8), the control group, underwent a sham operation on the unilateral testis without inducing testicular torsion. In groups B, C, and D (n = 5 each), unilateral testicular torsion was induced, and, after 3, 6 or 24 h, respectively, detorsion was performed. In group E (n = 5), permanent unilateral testicular torsion was applied. Contrast-enhanced ultrasound was used to observe the blood perfusion of the contralateral testis at the following stages: pre-torsion (preopration), immediately post-torsion (postopration), pre-detorsion, immediately post-detorsion, and late-stage post-detorsion (6–12 h post-detorsion in groups B–D) or at a similar time point (15–21 h post-torsion in group E). Time-intensity curves were generated, and the following parameters were derived and analyzed: arrival time, time to peak intensity, peak intensity, and half-time of the descending peak intensity. The analysis revealed that blood perfusion of the contralateral testis increased immediately after testicular torsion on the opposite side (P < 0.05), which increased with prolonged testicular torsion of the other testis. This research demonstrated that contrast-enhanced ultrasound was valuable in evaluating blood perfusion of the contralateral testis after unilateral testicular torsion.     

未成熟大鼠睾丸单侧扭转后对健侧血流和组织学的影响

目的:观察未成熟大鼠睾丸单侧扭转后对健侧睾丸血流供应和组织学的影响,并比较不同处理方法的疗效。方法:建立Wistar3周龄大鼠左侧睾丸扭转模型,分别建立对照组、扭转组、扭转复位组和扭转切除组,每组10只。彩色多普勒测量各组术前、术后8h(即扭转复位或切除术后2h)、12h、24h、72h右侧睾丸动脉收缩期最大血流速度,并于对照组和扭转组术后2h,扭转复位组和扭转切除组第1次术后12h各取2只大鼠右侧睾丸进行组织病理学观察。各组喂养至9周龄时分别取右侧睾丸进行组织学观察及检测各组大鼠右侧睾丸的生精小管直径(STD)、生精上皮细胞计数(CMSE)和睾丸活检评分(TBS)。结果:①未成熟睾丸左侧扭转后,右侧睾丸的血供呈持续性增加。②扭转组、扭转复位组和扭转切除组右侧睾丸均有不同程度的间质水肿和超微结构改变。③9周龄时扭转组、扭转切除组右侧睾丸重量均较对照组显著增加(P<0.01);各组大鼠STD、CMSE、TBS均无显著性差异(P>0.05)。结论:未成熟大鼠睾丸单侧扭转后可引起对侧睾丸的血供增加和组织学改变,轻微损伤后扭转复位和睾丸切除预后效果相似。     

Effects of unilateral testicular torsion on the blood flow of contralateral testis--an experimental study on dogs

The effects of unilateral testicular torsion on the blood flow of the contralateral testis were investigated. Fourteen adult male dogs were recruited. Seven dogs underwent unilateral testicular torsion of 4 h duration, and the other seven dogs had a control operation. Testicular blood flow was determined by colour Doppler ultrasonography before and after the testicular torsion. Bilateral orchidectomy was performed at the end of the study and histopathological changes were evaluated. Values of peak systolic velocity, end diastolic velocity, and resistive index were not statistically significant between ipsilateral and contralateral testes in the study group (p > 0.05). On comparison with the control group, blood flow in the contralateral testes showed no statistically significant difference (p > 0.05). Oedema and congestion were seen on ipsilateral testes in the study group. No histopathological changes were noted on the contralateral testes. Minimal oedema and congestion secondary to manipulation were found in the control operation testes. We conclude that unilateral testicular torsion does not decrease contralateral testicular blood flow as shown by colour Doppler ultrasonography.     

Flow cytometric DNA analysis demonstrates contralateral testicular deterioration in experimental unilateral testicular torsion of prepubertal rats

Summary. It has been postulated that unilateral testicular torsion causes damage to the contralateral testis and reduces fertility. However, in animal studies such an effect has not been fully proven by histopathologic examination or other conventional assays of spermatogenesis. We investigated the effect of unilateral testicular torsion on contralateral spermatogenesis in prepubertal rats using quantitative flow cytometric DNA analysis. Male rats were divided into three groups which underwent sham-operation, simple hemiorchiectomy or unilateral testicular torsion. Five weeks after these operations, fertility and spermatogenesis by flow cytometry were evaluated. No significant differences were observed in body weight, contralateral testicular weight or serum testosterone concentration among the three experimental groups. In the torsion group, mean seminiferous tubular diameter, number of foetuses, fertility rate and percentage of haploid cells were all significantly decreased compared to the other two groups. These results suggest that unilateral testicular torsion causes damage to the contralateral testis and consequently can reduce the future fertility of prepubertal rats.     

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.     

Capsaicin in albino rats prevents contralateral testis from the damaging effects posed by ipsilateral testis that underwent torsion.

OBJECTIVE: To evaluate the effect of capsaicin, a powerful neurotoxin selective to afferent nerves, on contralateral testicular damage in ipsilateral testicular torsion. METHODS: Forty male albino rats were randomly allocated into five groups. No operation was performed in group one. After intraperitoneal administration of 0.9% NaCl, rats underwent a sham operation in group 2 and testicular torsion in group 3. In groups 4 and 5 rats underwent sham operation and testicular torsion, respectively after intraoperitoneal capsaicin injection. Contralateral testes were harvested on the fifteenth day of the experiment and mean seminiferous tubular diameters and mean testicular biopsy scores were recorded for each testis. The values were compared through analysis of variance (ANOVA) with Turkey-Kramer multiple comparisons test and p values less than 0.05 were considered to be significant. RESULTS: Mean testicular biopsy scores and mean seminiferous tubular diameters of group 5 was significantly higher than the group 3. There was no difference between the groups 1, 2, 4, and 5 when these two parameters are concerned. CONCLUSION: Capsaicin effectively prevents contralateral testicular damage encountered following ipsilateral testicular torsion. The inhibition of afferent impulses from the ipsilateral testis under distress prevents contralateral testicular injury, and provides additional data to support the role of an autonomic reflex arc in contralateral testicular injury.     

On unilateral testicular and epididymal torsion: no effect on the contralateral testis

It is often stated that unilateral testicular torsion results in damage to the contralateral testis; however, there are a growing number of experimental and clinical papers which suggest this is not so. Conflicting results from experimental studies confuse the issue and may be due, among other things, to some specifics of the experimental model. In the present paper, we have examined bilateral rat testes 30 and 60 days after 720 degrees torsion to determine 1) the effect of unilateral testicular torsion with and without the inclusion of epididymal torsion, 2) the effect of relatively chronic torsion (24 hr., 10 day) versus relatively acute torsion (two hr., four hr.), and 3) the effect of establishing the model using scrotal surgery versus using an abdominal approach. Bilateral testicular histology, testis wt. (gm.), cauda epididymal sperm concentrations (sp./ml.), and cauda sperm motility scores (0-4) were examined. Ipsilateral testicular torsion or testicular plus epididymal torsion of two hr. or four hr. duration significantly reduced (p less than .05) ipsilateral testis weights, sperm concentrations, and motility scores, and disrupted normal tissue histology. Contralateral testicles were not altered. Epididymal ischemia alone produced no significant ipsilateral or contralateral effects. Chronic torsion (one day, 10 days) also destroyed ipsilateral testis function without altering the contralateral testicles. The occult cryptorchidism associated with the scrotal approach to establishing the torsion model had no effect on contralateral testicles. In no group, using either Lewis rats or Sprague-Dawley rats, were contralateral testicles altered by unilateral testicular torsion. These results plus recent clinical reports indicate that contralateral testicular damage due to ipsilateral torsion is hardly a proven phenomenon, let alone a significant factor contributing to male infertility.     

Late changes of the testicular tissue in experimental torsion of the spermatic cord (author's transl)

In three experimental groups and a control group unilateral or bilateral torsion of the testicle were carried out in 195 mature rats. The testicles were retorted at various intervals up to 24 hours. Four weeks and three months following the torsion the retorted as well as the contralateral normal testicles were examined morphologically and histologically. A total testicular torsion is fully reversable after one hour in all cases and after 2 hours in 40% of the cases. The Sertoli cells are destroyed after 6 hours and the Leydig cells after 10 hours. The time causing irreversable tissue damage therefore appears to be shorter than generally assumed, and the germinative epithelium is reacting faster than the testosterone producing Leydig cells. No changes were noted in the contralateral normal testis.     

Reperfusion injury after detorsion of unilateral testicular torsion

Summary Reperfusion injury has been well documented in organs other than testis. An experimental study was conducted to investigate reperfusion injury in testes via the biochemical changes after unilateral testicular torsion and detorsion. As unilateral testicular torsion and varicocele have been shown to affect contralateral testicular blood flow, reperfusion injury was studied in both testes. Given that testicular blood flow does not return after 720° testicular torsion lasting more than 3 h, the present study was conducted after 1 and 2 h of 720° torsion. Adult male albino rats were divided into seven groups each containing ten rats. One group served to determine the basal values of biochemical parameters, two groups were subjected to 1 and 2 h of unilateral testicular torsion respectively, two groups were subjected to detorsion following 1 and 2 h of torison respectively, and two groups underwent sham operations as a control. Levels of lactic acid, hypoxanthine and lipid peroxidation products were determined in testicular tissues. Values of these three parameters obtained from the sham operation control groups did not differ significantly from basal values (P>0.05). All three parameters were increased significantly in both ipsilateral and contralateral testes after unilateral testicular torsion when compared with basal values (P<0.01 and P<0.05, respectively). Detorsion caused significant changes in lipid peroxidation products levels in ipsilateral but not in contralateral testes when compared with values obtained after torsion (P<0.01 and P>0.05, respectively). It is concluded that ipsilateral testicular torsion causes a decrease in perfusion not only in the ipsilateral but also in the contralateral testis. Additionally, detorsion following up to 2 h of 720° torsion causes reperfusion injury in ipsilateral but not in contralateral testis.     

Effect of testicular torsion on contralateral testis and fertility in mature rats

The effect of unilateral testicular torsion on the contralateral testis and the fertility rate was studied in Charles River adult rats. Animals were divided into groups that underwent a sham operation or torsion and ligation of the left testicular vessels followed by orchiectomy after 24 h, orchiectomy after 48 h, release of the ligature after 24 h, release of the ligature after 48 h, and no further treatment following ligation. Another group of animals underwent unilateral orchiectomy. After 8 weeks animals were allowed to mate and were sacrificed 2 weeks later. The results did not point to either histological alterations in the contralateral testis or impairment of fertility in any group of treatment compared with the control.     

Torsion of only spermatic cord in the absence of testis and/or epididymis results in contralateral testicular hypoxia

Unilateral spermatic cord torsion in the presence or absence of ipsilateral testis causes hypoxia in the contralateral testis. An experimental study was conducted to find the most important structure that causes contralateral testicular hypoxia following ipsilateral twisting. In five groups each consisting of 10 rats sham operations, epididymoorchiectomy, spermatic cord torsion, spermatic cord torsion following subepididymal orchiectomy or spermatic cord torsion following epididymoorchiectomy were performed. Lactic acid, hypoxanthine and thiobarbituric acid reactive products of lipid peroxidation (TBAR) were determined in the contralateral testis. While lactic acid, hypoxanthine and TBAR values did not differ significantly following sham and epididymoorchiectomy procedures, evaluation of other groups revealed significantly increased values compared with sham and epididymoorchiectomy groups. Since torsion of only spermatic cord and testicular vasculature causes contralateral testicular hypoxia, testis and epididymis do not seem to be mandatory for occurrence of contralateral testicular hypoxia. Testicular artery under distress seems to be the most important structure that results in contralateral testicular hypoxia following torsion.     

New animal model to evaluate testicular blood flow during testicular torsion.

BACKGROUND/PURPOSE: Unilateral testicular torsion is known to cause infertility because of damage to the contralateral testis. Testicular damage has been attributed to many different mechanisms, one of which is altered contralateral blood flow. In our experiment, in an effort to identify the reason for contralateral testicular injury, the authors developed an accurate method of measuring blood flow in both testes before, during, and after unilateral torsion. METHODS: Four- to 6-week-old piglets weighing 4 to 6 kg were studied. The animals were anesthetized, intubated, ventilated, and catheterized for vascular access. Piglets were assigned randomly to a sham group or a group undergoing 360 degrees or 720 degrees torsion of the left testis (n = 5 per group) for 8 hours, after which it was untwisted. Data were collected at baseline (T = 0), 8 hours of torsion (T = 8), and 1 hour after detorsion (T = 9). Mean arterial blood pressure and heart rate were monitored continuously. Testicular blood flow was determined using radiolabeled microspheres. Blood flow data were evaluated by analysis of variance. RESULTS: In the 360 degrees torsion group, blood flow changes were insignificant during torsion and after detorsion. In the 720 degrees torsion group, blood flow to the twisted testis was reduced significantly, whereas the contralateral testis was unaffected. One hour after detorsion, blood flow to both testes was increased significantly. CONCLUSIONS: The authors describe a new animal model to evaluate testicular blood flow during and after testicular torsion. Increased blood flow after detorsion may be the cause of testicular damage in patients with unilateral testicular torsion.