Antioxidant procyanidin B2 protects oocytes against cryoinjuries via mitochondria regulated cortical tension

Background:Irreversible cryodamage caused by oocyte vitrification limited its wild application in female fertility preservation.Antioxidants were always used to antagonist the oxidative stress caused by vitrification.However,the comprehensive mechanism underlying the protective role of antioxidants has not been studied.Procyanidin B2(PCB2)is a potent natural antioxidant and its functions in response to vitrification are still unknown.In this study,the effects of PCB2 on vitrified-thawed oocytes and subsequent embryo development were explored,and the mechanisms underlying the protective role of PCB2 were systematically elucidated.Results:Vitrification induced a marked decline in oocyte quality,while PCB2 could improve oocyte viability and further development after parthenogenetic activation.A subsequent study indicated that PCB2 effectively attenuated vitrification-induced oxidative stress,rescued mitochondrial dysfunction,and improved cell viability.Moreover,PCB2 also acts as a cortical tension regulator apart from strong antioxidant properties.Increased cortical tension caused by PCB2 would maintain normal spindle morphology and promote migration,ensure correct meiosis progression and finally reduce the aneuploidy rate in vitrified oocytes.Further study reveals that ATP biosynthesis plays a crucial role in cortical tension regulation,and PCB2 effectively increased the cortical tension through the electron transfer chain pathway.Additionally,PCB2 would elevate the cortical tension in embryo cells at morula and blastocyst stages and further improve blastocyst quality.What's more,targeted metabolomics shows that PCB2 has a beneficial effect on blastocyst formation by mediating saccharides and amino acids metabolism.Conclusions:Antioxidant PCB2 exhibits multi-protective roles in response to vitrification stimuli through mitochondria-mediated cortical tension regulation.

Protective Effect of Procyanidin B2 on Acute Liver Injury Induced by Aflatoxin B1 in Rats

Objective This study aimed to explore the protective effect of procyanidin B2(PCB2)on acute liver injury induced by aflatoxin B1(AFB1)in rats.Methods Forty Sprague Dawley rats were randomly divided into control,AFB1,AFB1+PCB2,and PCB2 groups.The latter two groups were administrated PCB2 intragastrically(30 mg/kg body weight)for 7 d,whereas the control and AFB1 groups were given the same dose of double distilled water intragastrically.On the sixth day of treatment,the AFB1 and AFB1+PCB2 groups were intraperitoneally injected with AFB1(2 mg/kg).The control and PCB2 groups were intraperitoneally administered the same dose of dimethyl sulfoxide(DMSO).On the eighth day,all rats were euthanized:serum and liver tissue were isolated for further examination.Hepatic histological features were assessed by hematoxylin and eosin-stained sections.Weight,organ coefficient(liver,spleen,and kidney),liver function(serum alanine aminotransferase,aspartate aminotransferase,alkaline phosphatase,total bilirubin,and direct bilirubin),oxidative index(catalase,glutathione,superoxide dismutase,malondialdehyde,and 8-hydroxy-2′-deoxyguanosine),inflammation factor[hepatic interleukin-6(IL-6)m RNA expression and serum IL-6],and bcl-2/bax ratio were measured.Results AFB1 significantly caused hepatic histopathological damage,abnormal liver function,oxidative stress,inflammation,and bcl-2/bax ratio reduction compared with DMSO-treated controls.Our results indicate that PCB2 treatment can partially reverse the adverse liver conditions induced by AFB1.Conclusion Our findings indicate that PCB2 exhibits a protective effect on acute liver injury induced by AFB1.