Figure 5. A schematic diagram of the polyol pathway in COC and the mechanism of the effect of sorbitol accumulation on oocyte quality (in vivo or in vitro) of aged mice. Abbreviations: PPP: pentose phosphate pathway; HBP: hexosamine biosynthesis pathway; TCA: tricarboxylic acid cycle; OXPHOS: oxidative phosphorylation; NADPH: nicotinamide adenine dinucleotide phosphate (reduced form); PRPP: 5-phosphoribosyl-1-pyrophosphate; GSSG: glutathione (oxidized form); GSH: glutathione (reduced form); ROS: reactive oxygen species.