Abstract: Objective: To investigate the regulatory effect of equol (Eq) on the susceptibility to metabolic syndrome (MS) in the offspring of rats with gestational diabetes mellitus (GDM). Methods: Twenty female SD rats were divided into two groups: the normal group, which was fed a normal diet, and the GDM group, which was fed a high-fat diet (HFD) combined with intraperitoneal injection of streptozotocin. Each female rat was caged with a male to establish a normal pregnancy group and a GDM pregnancy group. The male offspring from the normal pregnancy group were randomly divided into two subgroups: blank control and MS model control. The male offspring from the GDM pregnancy group were randomly divided into five subgroups: MS model, low-, medium- and high-dose Eq (intragastric administration of 20, 40 and 80 mg/kg of Eq, respectively) and positive control (5 mg/kg of simvastatin). The blank control group was fed a normal diet, and the other groups were fed a HFD, with 8 rats in each group. The serum glucose and lipid metabolism indexes, oxidative stress and inflammation levels of GDM offspring rats were detected by commercial kits, and the degree of liver steatosis was observed by hematoxylin-eosin (HE) staining. Results: Compared with the MS group, Eq reduced the Lee’s index, final body mass and liver index of GDM offspring rats, and high-dose Eq decreased the Lee’s index by 13.9% (P < 0.01). Meanwhile, high-dose Eq significantly reduced serum triglyceride (TG), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels (P < 0.05), highly significantly increased serum high-density lipoprotein cholesterol (HDL-C) levels (P < 0.01), and significantly reduced serum fasting blood glucose (FBG) and fasting insulin (FINS) levels (P < 0.05). Furthermore, it highly significantly lowered serum malondialdehyde (MDA), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels and increased serum glutathione peroxidase (GSH-Px) levels (P < 0.01). Conclusion: GDM offspring are more susceptible to MS than the offspring of normal pregnant rats. Eq can significantly improve abnormal glucose and lipid metabolism in GDM offspring, enhance antioxidant capacity, alleviate inflammation, and reduce MS in multiple ways.

Key words: equol, metabolic syndrome, offspring of rats with gestational diabetes mellitus, glucose and lipid metabolism, oxidative stress, inflammation level