Positive Correlation of The Post-thaw Motility with the Motility following A Short Oxidative Challenge in Ram Epididymal Spermatozoa

Background: The spermatozoa of different donors have dif-ferent freezablity. The aim of the present study was investigat-ing the possible underlying causes of this difference. Moreover, finding a criterion that could predict the freezablity of different semen samples was another aim of this study.Materials and Methods: Testes of sexually mature rams were collected in a local abattoir and transported to the laboratory. In the laboratory, epididymal spermatozoa were recovered from the cauda epididymis and re-suspended in TCFE extender (Tris, citric acid, fructose, egg yolk). After motility assessment using a computer-assisted sperm analysis system (CASA), a sample of recovered spermatozoa were diluted in the TCFE extender (1% egg yolk) at 3×107 sperm/ml and then 50 µM H2O2 was added to the suspension. After that, the sperm suspensions were incubated at 37˚C. After 30 minutes, the motility of incubated samples was analyzed. At the same time, the recovered sperma-tozoa were undergone freezing process. At least one week af-ter freezing, the frozen samples were thawed and their motility analyzed. This experiment was performed in 10 replicates (10different testes). Finally, by using IBM SPSS 20, the Pearson’s correlation between the post-thaw (PT) motility parameters and post-oxidative challenge (POC) motility parameters were cal-culated.Results: There was a correlation between PT total motility and POC total motility (r=0.757, n=10, P<0.001). Moreover, there was a correlation between PT progressive motility and POC to-tal motility (r=0.775, n=10, P=0.024).Conclusion: The results of the present study showed that freez-ability of spermatozoa might be related to their sensitivity to the oxidative stress. Furthermore, the degree of sensitivity to a mild oxidative challenge might predict the freezability of, at least, ovine epididymal spermatozoa.

کلیدواژه ها:

Oxidative stress ، Cryosurvival ، Spermatozoa ،