Cinnamtannin B-1 prevents lipoperoxidation in thawed red deer spermatozoa

Antioxidants could improve sperm media, extending the viability of spermatozoa. Cinnamtannin B-1 (CNB-1) is a naturally occurring Atype proanthocyanidin found in a limited number of plants including Linderae umbellateae and L. nobilis. Epididymal sperm samples from six stags were used in this experiment. Thawed sperm samples were pooled. The protective ability of CNB-1 was tested on red deer spermatozoa incubated at 37°C. Cryopreserved spermatozoa were thawed and incubated with 0, 0.1, 1, 10 and 100 lM of CNB-1, with or without oxidative stress (100 lM Fe2+). Viability (YO-PRO-1/IP), acrosome status and lipoperoxidation (C11-BODIPY 581/591) were checked at 0, 2 and 4 h. For the statistical analysis, we used the R statistical environment. To analyze the effects of time, antioxidant and supplement (none, oxidant, and/or antioxidant) on sperm parameters, we used linear mixed-effects models. We replicated the experiment six times. High concentrations of CNB-1 (100 lM) preserved acrosome status in oxidized samples after 4 h of incubation (p < 0.05). Moreover, lower concentrations of CNB-1 showed limited protection against lipoperoxidation although high concentrations (10 and 100 lM) lowered lipoperoxiation in oxidized samples after 2 h of incubation (p = 0.03) and 4 h (p = 0.04). CNB-1 seems a promising new antioxidant, but its particular effects on sperm physiology must be further studied