Effect of caspase inhibitor Z‐VAD‐FMK on bovine sperm cryotolerance

Abstract

The aim of this study was to evaluate the treatment of bovine semen with the pan‐caspase inhibitor benzyloxycarbonyl‐Val‐Ala‐Asp‐fluoromethyl ketone (Z‐VAD‐FMK), before or after freezing on semen quality. After the initial assessment, sperm from 4 bulls were pooled (Experiment 1) and cryopreserved in BioXcell containing 0, 20 and 100 μM Z‐VAD‐FMK. After thawing semen viability, motility, membrane integrity, as well as DNA fragmentation and ΔΨm were evaluated. In Experiment 2, bovine frozen/thawed sperm were incubated for 1 hr with 0, 20 and 100 µM Z‐VAD‐FMK before assessing the semen quality. The treatment with Z ‐VAD‐FMK before cryopreservation improved post‐thawing sperm motility compared to the control group (p < .05), while no differences were recorded in sperm viability and membrane integrity among groups (on average 86.8 ± 1.5 and 69.1 ± 1.4, respectively). Interestingly, at the highest concentration, DNA fragmentation decreased (p < .05), while the percentage of spermatozoa with high ΔΨm increased (p < .05). The results of Experiment 2 showed that 1‐hr treatment with Z‐VAD‐FMK did not affect sperm motility and viability (on average 63.4 ± 5.8 and 83.7.1 ± 1.2, respectively). However, Z‐VAD‐FMK improved sperm membrane integrity (p < .05) and at the highest concentration tested decreased the proportion of sperm showing DNA fragmentation (p < .05). No differences were recorded in the percentage of spermatozoa with high ΔΨm (on average 57.0 ± 11.4). In conclusion, the treatment with 100 µM of the caspase inhibitor Z‐VAD‐FMK before freezing increased bovine sperm mass motility and ΔΨm, while decreasing sperm DNA fragmentation. Treatment of semen after thawing with 100 µM Z‐VAD‐FMK improved sperm membrane integrity and reduced DNA fragmentation.

PM2.5 induces autophagy‐dependent ferroptosis by endoplasmic reticulum stress in SH‐SY5Y cells

“…The fluorescence intensity increased firstly and then decreased as the exposure dose went up, and the most vigorous fluorescence intensity appeared in the 80 μg/mL PM 2.5 exposure group. The apoptosis inhibitors Z-VAD-FMK (Pagano et al, 2020) (Z-VAD-FMK irreversibly binds to activated Caspases to block the cell apoptosis) could increase the cell viability of the 40, 80, and 160 μg/mL PM 2.5 exposed groups to 4%, 10%, and 4% respectively, which was consistent with Annexin V staining results. This suggests that apoptosis was the main mode of death in the 80 μg/mL PM 2.5 group.…”

mTOR interacts with AIF to positively regulate autophagy

“…S4a), no cleavage of PARP-1, which serves as a marker of cells undergoing caspase-dependent apoptosis, was observed in H 2 O 2 -treated cells (Fig. S4b), whereas Z-VAD-FMK, a well-known pan-caspase inhibitor 33 , showed no effect on H 2 O 2 -induced cell viability loss (Fig. S4c).…”

Sperm freezing damage: the role of regulated cell death

“…Ideally, Z-VAD could markedly reduce the death indicators of frozen-thawed semen, including improved vitality and plasma membrane integrity. However, the addition of Z-VAD before freezing had no significant effect on the integrity of the plasma membrane of frozen-thawed bovine sperm, and the addition of Z-VAD after thawing had no significant effect on the viability of bovine sperm [ 91 ]. In addition, similar conclusions were drawn from the frozen semen of dogs; regardless of whether Z-VAD was added before or after freezing, sperm motility and plasma membrane integrity were not improved [ 92 ].…”