Localization of NGF and nNOS in varicocele-induced rat testis

Effect of Zinc on Spermatogenesis and Sperm Chromatin Condensation in Bleomycin, Etoposide, Cisplatin Treated Rats

Objective

The incidence rate of testicular cancer among young males is high. Co-administration of bleomycin, etoposide and cisplatin (BEP) has increased survival rate of patients with testicular cancer. Although BEP is one of the most effective treatment for testicular cancer, but it severely affects the reproductive system that ultimately leads to infertility. In addition to its antioxidant activity, zinc has an important role in progression of spermiogenesis. This study aimed to evaluate the effect of zinc on sperm parameters, chromatin condensation and testicular structure after BEP treatment.

Materials and Methods

In this experimental study, 40 male rats were divided into 4 groups (control, BEP, BEP+ zinc and zinc) and examined for 2 spermatogenesis periods (i.e. 18 weeks). The rats in BEP and BEP+ zinc group were treated with BEP at appropriate doses (0.75, 7.5, and 1.5 mg/kg) for three cycles of three weeks. Zinc at a dose of 10 mg/kg/day was administered to BEP+ zinc and zinc groups. After 18 weeks, we assessed sperm parameters, and excessive histone in sperm chromatin using aniline blue staining, as well as testicular structure and germ line cells using periodic acid-Schiff staining.

Results

After BEP treatment, significant decreases were observed in normal sperm morphology, motility, and concentration, as well as alterations in rat sperm chromatin condensation and testicular tissue (P<0.001). Furthermore, after zinc consumption for 9 weeks, we observed significant improvements of sperm parameters and chromatin condensation as well as a significant retrieval of spermatogonia, leydig cells and tubular architecture (P<0.05).

Conclusion

Zinc administration after chemotherapy with BEP in testicular cancer might be potentially useful in declining the off target consequence associated with oxidative stress.

Expression of NOS isoforms in internal spermatic veins of infertile men with varicocele

Although varicocele is a relatively common entity encountered in the evaluation of infertile men, the exact pathophysiology still remains unclear. Recently, as previously widely investigated in various parts of human circulatory system, nitric oxide synthase (NOS) and its product, nitric oxide (NO) have been thought to play a role in the development of varicocele and thus male infertility. In this study, we determined the concentration of NO metabolite and the expression of NOS isoforms in the internal spermatic (ISV) and superficial branch of inferior epigastric veins of infertile men with varicocele. The study included 60 infertile men with clinically unilateral or bilateral varicocele. Expression of inducible and endothelial NOS (iNOS and eNOS) isoforms were investigated in tissue arrays of internal spermatic and superficial branch of inferior epigastric veins with immunohistochemistry. NO metabolite (nitrite) levels were measured using the calorimetric method. A significantly higher expression of eNOS was observed in the varicose veins (mean score: 2.25 and 1.55, respectively; p = 0.0001). However, statistically, there was no significant difference for expression of iNOS between varicose and control veins (p = 0.094). The nitrite concentration and NOS expression were not found to be correlated with clinical variables (varicocele grade, maximum varicose vein diameter, and sperm concentration, motility, and morphology) (p > 0.05). As a result, the significantly higher expression of eNOS in ISV may be responsible for the development of varicocele, although this finding is not accompanied by an increase in NO concentration. Still, the pattern of the relationship between varicocele and increased eNOS expression warrants further investigation.

Immunolocalization of glial cell-derived neurotrophic factor (GDNF) and its receptor GFR-alpha1 in varicocele-induced rat testis

The aim of the study was to determine the immunolocalisation of glial cell-derived neurotrophic factor (GDNF) and its receptor (GFRalpha1) in testicular dysfunction induced by experimental left varicocele. Male Wistar rats were divided randomly into two groups: a varicocele-induced group and a sham-operated group for 9, 11 and 13 weeks (each group n=6). After orchiectomy, part of the left testis from each animal was fixed, processed and embedded in paraffin wax for immunohistochemistry and the other part was fixed for ultrastructural investigations. GDNF immunoreactivity was localized in the interstitial space in Leydig cell cytoplasm and there was no significant difference (P=0.5) between the varicocele-induced groups at the various time points. GFRalpha1 localization was perinuclear in spermatids and cytoplasmic in Leydig cells. The decrease of GFRalpha1 immunoreactivity was significant (P=0.001) in varicocele-induced testis at 13 weeks when compared with the age-matched sham group. This is the first study to describe the immunolocalization patterns of GDNF and GFRalpha1 in a rat model of varicocele. Although there was no change in GDNF labelling at the different time points after varicocele, GFRalpha1 was significantly decreased in the 13-week group. Distribution of GDNF and its receptor GFRalpha1 in normal and varicocele-induced rat testes suggests both autocrine and paracrine regulation of spermatogenesis.