ObjectiveTo observe the effect of Zishen Tiaogan prescription on the oxidative stress injury in the rat model of diminished ovarian reserve （DOR） and explore the role of the Kelch-like ECH-associated protein 1 （Keap1）/nuclear factor E₂-related factor 2 （Nrf2）/heme oxygenase-1 （HO-1） signaling pathway. MethodsForty-eight female SD rats were randomly assigned into a normal group （n=12） and a modeling group （n=36）. The rats in the modeling group received subcutaneous injection of galactose （350 mg·kg^-1） combined with immobilization stress daily. After 28 days of modeling， 6 rats in the normal group and 6 rats in the modeling group were sacrificed to examine the modeling results. The successfully modeled rats were assigned into model， estradiol valerate （0.09 mg·kg^-1）， and low-， medium-， and high-dose （6.39， 12.78， 25.56 g·kg^-1， respectively） Zishen Tiaogan prescription groups. The intervention lasted for 4 weeks with 6 animals per group. Hematoxylin-eosin staining was used to observe the estrous cycle and the pathological changes in the ovarian tissue. The ovarian index was calculated. Enzyme-linked immunosorbent assay was employed to measure the serum levels of sex hormones and oxidative stress-related indexes. Western blot and real-time PCR were employed to determine the protein and mRNA levels， respectively， of Nrf2， Keap1 and HO-1 in the ovarian tissue. The positive expression of superoxide dismutase 2 （SOD2） in the ovarian tissue was detected by immunohistochemistry （IHC）. ResultsCompared with the normal group， the model group showed reduced follicles in the ovary， loose arrangement of the follicle granule layer， declined levels of anti-Mullerian hormone （AMH） and estradiol （E₂） in the serum， elevated levels of luteinizing hormone （LH） and follicle-stimulating hormone （FSH） （P<0.01）， lowered levels of superoxide dismutase （SOD）， catalase （CAT）， and glutathione （GSH） （P<0.01）， and increased accumulation of malondialdehyde （MDA） （P<0.01）. In addition， the modeling led to up-regulated protein and mRNA levels of Keap1 （P<0.01）， the expression of Nrf2 and HO-1 protein was significantly decreased （P<0.01）， the mRNA expression of Nrf2 was significantly decreased （P<0.05）， the mRNA expression of HO-1 was significantly decreased （P<0.01）， in the ovarian tissue. Compared with model group， the estradiol valerate and low-， medium-， and high-dose Zishen Tiaogan prescription groups showed increases in the ovarian index （P<0.01） and serum E₂ and AMH levels （P<0.01）， declined levels of FSH and LH （P<0.01）， increased follicles in the ovary， elevated levels of SOD， CAT， and GSH， and reduced accumulation of MDA （P<0.05， P<0.01）. Furthermore， these groups showcased down-regulated protein and mRNA levels of Keap1 （P<0.01）， the expression of Nrf2 protein was significantly increased （P<0.01）， the expression level of HO-1 protein was increased （P<0.05，P<0.01）， and increased positive expression of SOD2 （P<0.01）. ConclusionZishen Tiaogan prescription can regulate the serum levels of hormones， down-regulate the expression of Keap1， up-regulate the expression of Nrf2， HO-1， and SOD2， enhance the antioxidant capacity， and reduce the peroxidation damage in the ovarian tissue to improve the ovarian reserve function in the rat model of DOR. High-dose Zishen Tiaogan prescription demonstrated the best effect and the mechanism is associated with the regulation of the Keap1/Nrf2/HO-1 pathway.

ObjectiveTo observe the effect of Zishen Tiaogan prescription on the oxidative stress injury in the rat model of diminished ovarian reserve （DOR） and explore the role of the Kelch-like ECH-associated protein 1 （Keap1）/nuclear factor E₂-related factor 2 （Nrf2）/heme oxygenase-1 （HO-1） signaling pathway. MethodsForty-eight female SD rats were randomly assigned into a normal group （n=12） and a modeling group （n=36）. The rats in the modeling group received subcutaneous injection of galactose （350 mg·kg^-1） combined with immobilization stress daily. After 28 days of modeling， 6 rats in the normal group and 6 rats in the modeling group were sacrificed to examine the modeling results. The successfully modeled rats were assigned into model， estradiol valerate （0.09 mg·kg^-1）， and low-， medium-， and high-dose （6.39， 12.78， 25.56 g·kg^-1， respectively） Zishen Tiaogan prescription groups. The intervention lasted for 4 weeks with 6 animals per group. Hematoxylin-eosin staining was used to observe the estrous cycle and the pathological changes in the ovarian tissue. The ovarian index was calculated. Enzyme-linked immunosorbent assay was employed to measure the serum levels of sex hormones and oxidative stress-related indexes. Western blot and real-time PCR were employed to determine the protein and mRNA levels， respectively， of Nrf2， Keap1 and HO-1 in the ovarian tissue. The positive expression of superoxide dismutase 2 （SOD2） in the ovarian tissue was detected by immunohistochemistry （IHC）. ResultsCompared with the normal group， the model group showed reduced follicles in the ovary， loose arrangement of the follicle granule layer， declined levels of anti-Mullerian hormone （AMH） and estradiol （E₂） in the serum， elevated levels of luteinizing hormone （LH） and follicle-stimulating hormone （FSH） （P<0.01）， lowered levels of superoxide dismutase （SOD）， catalase （CAT）， and glutathione （GSH） （P<0.01）， and increased accumulation of malondialdehyde （MDA） （P<0.01）. In addition， the modeling led to up-regulated protein and mRNA levels of Keap1 （P<0.01）， the expression of Nrf2 and HO-1 protein was significantly decreased （P<0.01）， the mRNA expression of Nrf2 was significantly decreased （P<0.05）， the mRNA expression of HO-1 was significantly decreased （P<0.01）， in the ovarian tissue. Compared with model group， the estradiol valerate and low-， medium-， and high-dose Zishen Tiaogan prescription groups showed increases in the ovarian index （P<0.01） and serum E₂ and AMH levels （P<0.01）， declined levels of FSH and LH （P<0.01）， increased follicles in the ovary， elevated levels of SOD， CAT， and GSH， and reduced accumulation of MDA （P<0.05， P<0.01）. Furthermore， these groups showcased down-regulated protein and mRNA levels of Keap1 （P<0.01）， the expression of Nrf2 protein was significantly increased （P<0.01）， the expression level of HO-1 protein was increased （P<0.05，P<0.01）， and increased positive expression of SOD2 （P<0.01）. ConclusionZishen Tiaogan prescription can regulate the serum levels of hormones， down-regulate the expression of Keap1， up-regulate the expression of Nrf2， HO-1， and SOD2， enhance the antioxidant capacity， and reduce the peroxidation damage in the ovarian tissue to improve the ovarian reserve function in the rat model of DOR. High-dose Zishen Tiaogan prescription demonstrated the best effect and the mechanism is associated with the regulation of the Keap1/Nrf2/HO-1 pathway.