Moment of induction and duration of experimental varicocele in rats: effects on semen quality

Abstract

Purpose: Varicocele is a condition known to cause damage to seminal parameters and sperm function. Furthermore, it has been hypothesized that the varicocele effect on fertility is time-dependent; however, little is known about the consequences of its establishment time on reproductive organs and/or sperm function. This study aimed to evaluate the effect of the duration of experimental varicocele on reproductive organs, sperm parameters, and sperm function.

Materials and methods: Varicocele induction surgeries were performed in Wistar rats aged 40 or 100 days old. At 160-day-old, analyses were performed, including biometry of reproductive organs (prostate, seminal vesicles, epididymis, and testis), sperm parameters (vitality, morphology, and motility), and sperm function tests (nuclear DNA integrity, acrosome integrity, and mitochondrial activity).

Results: The analysis of the biometry of reproductive organs showed no differences between distinct ages in which varicocele was induced. The total abnormal sperm morphology was bigger in animals with varicocele induced to 100 days old than in animals with varicocele induced to 40 days old. Regarding nuclear DNA integrity, animals of varicocele induced to 100 days old showed worse results compared to animals of varicocele induced to 40 days old. Other parameters analyzed showed no differences between varicocele groups.

Conclusion: In this study conducted on rats, we conclude that varicocele adversely affects sperm, particularly its function. However, we did not observe a negative progressive effect on sperm.

Keywords: AcrosomeGenitalia; Genitalia; Spermatozoa.

Figure 1. Photomicrographs of rat sperm after performing the following evaluations.

Figure 2. Photomicrographs of rat sperm after performing the following evaluations: A-D) nuclear DNA integrity by alkaline comet assay: A) Comet grade I (observed nucleus and no DNA migration), B) Comet grade II (observed nucleus and little DNA migration), C) Comet grade III (observed nucleus and intense DNA migration), and D) Comet grade IV (no observed nucleus and intense DNA migration); E and F) Acrosome integrity by a peanut agglutin in conjugated to a fluorescein isothiocyanate probe (PNA-FITC): E) intact acrosome, and F) non-intact acrosome; G and H) Mitochondrial activity by 3,3’-diaminobenzidine chromogen (DAB): G) Class I (100% staining - arrow), Class II (more than 50% stained - dashed arrow), Class III (less than 50% stained - head arrow), H) Class IV (without staining).