Effects of Lactate on Long-term Cognitive Impairment After Repeated Sevoflurane Inhalation in Neonatal Rats by Regulating SIRT3/PINK1/Parkin Pathway Mediated Mitophagy

MI Qiurong; MA Li; ZHAO Yongwei

doi:10.13730/j.issn.2097-2148.2025.02.002

Abstract：Objective To investigate the effects of mitophagy mediated by the lactate-regulated sirtuin 3(SIRT3)/PTEN induced putative kinase 1(PINK 1)/Parkin pathway on long-term cognitive impairment after repeated sevoflurane inhalation in neonatal rats.Methods A total of 60 6 d rats were randomly divided into control group,model group,lac-tate group and lactate+3-(1H-1,2,3-triazol-4-yl)pyridine(3-TYP)group,with 15 rats in each,On the 42th day after birth,the open field test was conducted to detect the rat's locomotor ability,on the 43th day,the novel object recognition test was conducted to evaluate the hippocampal memory of the rats,and on the 44th day,the contextual fear test was con-ducted to evaluate the hippocampal neural function.After the behavioral tests,the corresponding kits were used to detect the mitochondrial respiratory chain complex and SIRT3 activity,adenosine triphosphate(ATP)level,and nicotinamide adenine dinucleotide(NAD+)/reduced nico-tinamide adenine dinucleotide(NADH)ratio in the hippocampus;transmission electron microscopy was used to detect the ultrastructure of hippocampal neurons;Western blot was used to detect mitophagy in the hippocampus and the SIRT3/PINK1/Parkin pathway related proteins in the hippocampus.Results There was no significant difference in the total ex-ploration distance among the 4 groups of rats(all P＞0.05).Compared with the control group,the model group showed a decreased novel object recognition index,shorter time spent and stiffness in the central grid,lower mitochondrial com-plex Ⅰ activity,ATP level,NAD+/NADH and mitochondrial SIRT3 activity,obvious damage to hippocampal neurons,disordered mitochondrial structure,swelling,herniation of cristae,fewer autophagic vacuoles,increased expression of microtubule-associated protein 1 light chain 3B(LC3 Ⅱ/Ⅰ)and Beclin 1,lower expression of p62,and lower expression of SIRT3,PINK1 and Parkin(all P＜0.05).Compared with the model group,the lactate group showed increased novel object recognition index,longer time spent and stiffness in the central grid,higher mitochondrial complex Ⅰ activity,ATP level,NAD+/NADH and mitochondrial SIRT3 activity,improved mitochondrial structure,increased autophagic vacuoles,increased expression of LC3 Ⅱ/Ⅰ and Beclin 1,lower expression of p62 and higher expression of SIRT3,PINK1 and Parkin(all P＜0.05).Compared with the lactate group,the lactate+3-TYP group showed decreased novel object recognition index,shorter time spent in stiffness the central grid and lower mitochondrial complex Ⅰ activity,ATP level,NAD+/NADH,and mitochondrial SIRT3 activity,worsened mitochondrial damage,fewer autophagic vacuoles,lower expression of LC3 Ⅱ/Ⅰ and Beclin 1,higher expression of p62,and lower expression of SIRT3,PINK1 and Par-kin(all P＜0.05).Conclusion Lactate may improve long-term cognitive impairment induced by repeated sevoflurane ex-posure in neonatal rats by maintaining NAD+/NADH ratio,increasing mitochondrial SIRT3 activity and activating PINK1/Parkin pathway mediated mitophagy.