Angelica sinensis polysaccharide ameliorates endometriosis in rats by restoring autophagic homeostasis through inhibition of Keap1/Nrf2/HO-1-mediated oxidative stress

ObjectiveTo investigate whether Angelica sinensis polysaccharide ameliorates endometriosis by suppressing oxidative stress and thereby restoring autophagy via the Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway.MethodsRats were randomly divided into six groups (n=12 per group): normal control group, model control group, low-dose Angelica sinensis polysaccharide group, high-dose Angelica sinensis polysaccharide group, gestrinone group, and high-dose Angelica sinensis polysaccharide+Keap1 activator (recombinant Keap1 protein, rKeap1) group. Except for the normal control group, EMS models were established in all the other groups. After successful modeling, treatments were administered once a day for 4 weeks. The mass and volume of ectopic endometrial tissue were measured. Pathological changes, levels of reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) in uterine/ectopic endometrial tissue were assessed. The number of autophagosomes in uterine/ectopic endometrial tissue was observed using transmission electron microscopy. The relative fluorescence intensity of microtubule-associated protein light chain 3 (LC3) was detected by immunofluorescence staining. Western blot was used to measure the protein expression of LC3-II/LC3-I, p62, Keap1, nuclear Nrf2 and HO-1 in uterine/ectopic endometrial tissue.ResultsCompared with uterine endometrial tissue in normal control group, the model control group exhibited increased glandular proliferation in ectopic endometrial tissue, prominent vacuolization of glandular cells, and a large number of inflammatory cell infiltration. The levels of ROS, MDA, p62 and Keap1 were significantly increased (P<0.05). While the levels of SOD, autophagosome numbers, and relative fluorescence intensity of LC3 was weakened, and protein levels of LC3-II/LC3-I, nuclear Nrf2 and HO-1 were decreased (P<0.05). Compared with the model control group, the pathological damage, the mass and volume of ectopic endometrial tissue were alleviated in the low- and high-dose Angelica sinensis polysaccharide group and gestrinone group were demonstrated. The levels of ROS, MDA, p62 and Keap1 were decreased (P<0.05). While the levels of SOD, autophagosome numbers, and relative fluorescence intensity of LC3 was enhanced, and protein levels of, LC3-II/LC3-I, nuclear Nrf2 and HO-1 were increased (P<0.05). However, rKeap1 reversed the inhibitory effects of high-dose Angelica sinensis polysaccharide on oxidative stress and the restorative effects on autophagy homeostasis in EMS rats.ConclusionAngelica sinensis polysaccharide may improve EMS by inhibiting theactivation of the Nrf2/HO-1 pathway by Keap1, reducing oxidative stress in rats and restoring autophagy homeostasis.