Objective Based on the secreted frizzled-related protein 2(SFRP2)-Wnt/β-catenin signaling pathway,this study explored the effect and mechanism of Cuiru Keli(CRKL)in the treatment of postpartum hypogalactia.Methods A rat model of postpartum hypogalactia was established by gavaging 2 mL of 1.6 mg/mL bromocriptine mesylate to female rats on the third day after delivery.Female rats with a delivery time difference of less than 48 hours were selected and randomly assigned to 7 groups,including a normal group(without any modeling or medication),a model group,a CRKL low-dose group of model group model rats receiving CRKL at the dose of 3 g/kg,a CRKL medium-dose group of model rats receiving CRKL at the dose of 6 g/kg,a CRKL high-dose group of model rats receiving CRKL at the dose of 9 g/kg,a positive drug group of model rats receiving domperidone at the dose of 3 mg/kg,and a negative control(NC)group of model rats receiving normal saline.Each group contained 6 rats.Except for the normal and model groups,the remaining 5 groups were continuously administered with the respective intervention drugs at the specified doses by gavage once a day for 10 days.Changes in the total litter mass of the offspring in the 7 groups within 10 days were measured,and HE staining was performed to identify pathological changes in the mammary tissue(MT).Six groups of rats(excluding the positive control group)were used to observe the pathological changes of eosinophils in pituitary tissue.ELISA was performed to determine the content of prolactin(PRL)in serum,immunohistochemical staining was used to determine the expression of prolactin receptor(PRLR)in MT,and RT-qPCR was used to determine the mRNA expression of genes related to lactation in MT.Network pharmacology and molecular docking were used to study the therapeutic effect and mechanism of CRKL on postpartum hypogalactia,particularly whether it acted through the SFRP2-Wnt/β-catenin signaling pathway.The mechanism of CRKL treatment was further validated by detecting mRNA(RT-qPCR)and protein expression(Western blot)of related pathway genes.Cell experiments were conducted using primary culture rat mammary epithelial cells(RMEC)from rat MT.RMEC were divided into four groups,including a normal group(primary culture RMEC,untreated),SFRP2 overexpression group(primary cultured RMEC treated with SFRP2 overexpression vector),SFRP2 overexpression+CRKL group(receiving treatment for SFRP2 overexpression group plus 10% drug-containing serum),and negative control group(primary culture RMEC treated with empty vector).The effect of CRKL on the expression of lactation-related genes FASN,CSN2,and GLUT1 mRNA after SFRP2 overexpression was detected by RT-qPCR.Results In this study,CRKL was administered at a dose of 3 g/kg in the CRKL low-dose group,6 g/kg in the medium-dose group,and 9 g/kg in the high-dose group(P<0.05 or P<0.01).Compared with the model group,CRKL at all doses significantly increased the total litter weight gain of the offsprings within 10 days(P<0.05 or P<0.01),and effectively increased lactation(P<0.01),the area of mammary lobules,and the size and filling of acinar cavities.CRKL at all doses also increased the number of eosinophils that secreted PRL in the pituitary gland of the postpartum hypogalactia rat model,and increased the content of PRL in the serum(P<0.05 or P<0.01).CRKL promoted the secretion and expression of PRL in postpartum hypogalactic model rats.In addition,it significantly promoted the expression of genes related to milk fat,milk protein,and lactose synthesis in MT(P<0.05 or P<0.01).Network pharmacology predicted that the Wnt signaling pathway might be a key pathway for CRKL in treating postpartum hypogalactia.The molecular docking results showed that related chemical components in CRKL had good binding ability with CCND1 and SFRP2.Compared with the model group,CRKL at all doses inhibited the expression of SFRP2 gene in vivo(P<0.01)and activated the mRNA and protein expression of CCND1 and c-Myc in the Wnt/β-catenin signaling pathway in MT(P<0.05 or P<0.01).Cell experiments showed that,compared to the normal group,SFRP2 overexpression reduced the mRNA expression of milk synthesis-related genes FASN,CSN2,and GLUT1 in RMEC(P<0.01).The CCK8 results indicated that 10% of the drug-containing serum was the effective concentration administered to cells(P<0.01).After administering drug-containing serum,the expression of the lactation-related genes FASN,CSN2,and GLUT1 were up-regulated(compared with the SFRP2 overexpression group,P<0.01).Conclusion CRKL alleviates postpartum hypogalactia through the SFRP2-Wnt/β-catenin signaling pathway.SFRP2 might be a potential new target for the diagnosis and treatment of postpartum hypogalactia.This reveals a new mechanism of CRKL in treating postpartum hypogalactia and promotes its clinical application.

AIM: To investigate the effect of an effective component total sterone (TSR) of Echinops latifolius Tausch, the main component of a Chinese patent medicine Cuiru Keli (national drug standard WS3-413 (Z-085)-2003 (Z), on lactation and its possible mechanism. METHODS: After mating between male and female SD rats, 60 female rats were randomly divided into normal control group, model group, TSR low-dose and high-dose groups and prolactin granule positive control group, with 12 female rats in each group and 8 newborn rats in each nest. In addition to the normal control group, the rats in each group were intraperitoneally injected with levodopa 2 mg/kg once a day for 7 days from the second day of delivery. The rats in the normal control group were given normal saline by gavage once a day for 14 days. From the beginning of self-sufficiency, the single lactation of the female rats was measured every day until the 14th day, and then the female rats in each group were killed. Pathological HE staining was used to observe the morphological changes of mammary gland tissue in each group. ELISA was used to detect the levels of serum prolactin (PRL) and 5-hydroxytryptamine (5-HT). Immunohistochemistry was used to detect the distribution of PRL in mammary gland tissue of each group. Furthermore, Real-time qPCR was used to detect the expression of milk protein, milk fat related genes β-casein, FAS, ACC and the expression of canonical Wnt signaling pathway related genes β-catenin, c-Myc, CCND1, SFRP4, DNMT1, MeCP2 in mammary gland of each group. RESULTS: Both low and high dose TSR could significantly increase the single lactation volume, improve the pathological morphology of mammary gland, and increase the serum levels of PRL and 5-HT. TSR increased the distribution of PRL and up-regulated the expression of milk protein, milk fat related genes β-casein, FAS, ACC and canonical Wnt signaling pathway related genes β-catenin, c-Myc, CCND1, SFRP4, DNMT1, MeCP2.CONCLUSION: TSR can significantly promote lactation in lactation deficient rats, and its mechanism may be related to promoting the release of PRL and 5-HT in serum, increasing the distribution of PRL in mammary gland, up-regulating the milk protein and milk fat related genes and activating the canonical Wnt signal.