Regulation of Mitochondrial Ca2+ in Vitrified Bovine Oocytes by Ruthenium Red

Studies have shown that the developmental ability of vitrified mammalian oocytes is greatly impacted due to the serious damage of mitochondrial function induced by vitrification process. To solve this problem,in vitro matured bovine oocytes were divided into five groups,three of which were first vitrified using vitrification solution containing 0.5,1, 2 μmol/L ruthenium red (RR), then survived oocytes after thawing were cultivated in vitro maturation medium with the same concentration of RR as above for 0.5 h,meanwhile,the remained two groups of oocytes were as control, and one group was vitrified using vitrification solution without RR (vitrified control group) and the other group had no any treatment (fresh control group).Then the mitochondrial Ca²⁺ (mCa²⁺) level,ATP content and the developmental capacity of parthenogenetic embryos of oocytes in the five groups were detected to explore the effect of RR on mCa²⁺ level of vitrified bovine oocytes. The results showed that:①Vitrification significantly increased mCa²⁺ concentration in bovine oocytes (P <0.05), while RR significantly decreased mCa²⁺ concentration in vitrified bovine oocytes and there was no significant difference between fresh control group and 2 μmol/L RR group (P >0.05);②Vitrification significantly decreased ATP content in bovine oocytes (P <0.05),and the ATP content of 2 μmol/L RR group was significantly higher than that of vitrified control group and 0.5,1 μmol/L RR groups (P <0.05);③The cleavage rate and blastocyst rate of fresh control group were significantly higher than those of vitrified control group (P <0.05),while were no significant difference with 1 μmol/L RR group (P >0.05). In conclusion,the results showed that RR treatment could maintain the normal concentration of mCa²⁺ in vitrified bovine oocytes,protect the function of mitochondria and improve developmental competence of oocytes, which would provid theoretical basis to positively regulate the concentration of mCa²⁺,eventually improve the developmental competence and promote the extensive application of vitrified oocytes.