摘要Background Previous studies have shown that the vitrification of metaphase Ⅱ(MⅡ)oocytes significantly represses their developmental potential.Abnormally increased oxidative stress is the probable factor;however,the underlying mechanism remains unclear.The walnut-derived peptide TW-7 was initially isolated and purified from walnut protein hydrolysate.Accumulating evidences implied that TW-7 was a powerful antioxidant,while its prospective application in oocyte cryopreservation has not been reported.Result Here,we found that parthenogenetic activation(PA)zygotes derived from vitrified MⅡ oocytes showed elevated ROS level and delayed progression of pronucleus formation.Addition of 25 μmol/LTW-7 in warming,recov-ery,PA,and embryo culture medium could alleviate oxidative stress in PA zygotes from vitrified mouse MⅡ oocytes,furtherly increase proteins related to histone lactylation such as LDHA,LDHB,and EP300 and finally improve histone lactylation in PA zygotes.The elevated histone lactylation facilitated the expression of minor zygotic genome activa-tion(ZGA)genes and preimplantation embryo development.Conclusions Our findings revealed the mechanism of oxidative stress inducing repressed development of PA embryos from vitrified mouse Mil oocytes and found a potent and easy-obtained short peptide that could sig-nificantly rescue the decreased developmental potential of vitrified oocytes,which would potentially contribute to reproductive medicine,animal protection,and breeding.