Fig. 4

Effect of the combined treatment with a hydrogen sulfide donor and L-type Ca²⁺ channel activator. Na₂S (300 µM, (+)Na₂S) was used as the extracellular hydrogen sulfide donor, and BAY K6844 (0.1–10 µM; aCa) was used to activate L-type Ca²⁺ channels both alone ((−)Na₂S) and combined with Na₂S ((+)Na₂S). a–c The proportions of intact MII oocytes; cell death, including apoptosis or lysis; and parthenogenetically activated oocytes were determined, respectively. Different superscripts indicate statistically significant differences among experimental groups within a treatment (α, β, γ). Asterisks indicate a significant difference between treatments within the same aCa concentration (at α level less than 0.01)