[Role of Puerariae Lobatae Radix in Gegen Decoction for treatment of primary dysmenorrhea].

This study aimed to explore the characteristic role of Puerariae Lobatae Radix(PLR) in Gegen Decoction for the treatment of primary dysmenorrhea(PD). Estrogen(E_2) was combined with oxytocin to establish a mouse model of PD. The mice were randomly divided into a normal group, a model group, a Gegen Decoction group, a PLR-free Gegen Decoction group, a PLR group, and a positive drug group(ibuprofen). Writhing response times and writhing incubation of mice in each group were tested by behavio-ral assessment, and the serum levels of prostaglandin F_(2α)(PGF_(2α)), prostaglandin E_2(PGE_2), E_2, and progesterone(PROG) were detected by ELISA kits. Western blot method was adopted to detect cyclooxygenase-2(COX-2) and estrogen receptor alpha(ER_α) expression levels in uterine tissues. Doppler ultrasound was employed to detect changes in uterine artery blood flow in mice, including peak systolic blood flow velocity(maximum velocity), end-diastolic velocity(minimum velocity), peak systolic blood flow velocity/end-diastolic velocity(S/D), pulsatility index(PI), and resistive index(RI). Histopathological changes in the uterus were detected by HE staining. Based on the oxytocin-induced isolated uterine contraction model, the effects of Gegen Decoction, PLR-free Gegen Decoction, and PLR on the amplitude, frequency, and activity of isolated uterine contraction were compared to investigate the role of PLR in Gegen Decoction for the treatment of PD. The results showed that compared with the Gegen Decoction group, the PLR-free Gegen Decoction improved the indicators of PD except for E_2 content, ER_α expression, and uterine artery blood flow. PLR could significantly down-regulate the serum content of E_2 and the protein expression of uterine ER_α, and improve the uterine artery blood flow. The data suggested that PLR, as the sovereign drug of Gegen Decoction, might function in Gegen Decoction for the treatment of PD by mediating E_(2 )and improving the uterine artery blood flow.

Spasmolytic Mechanism of Aqueous Licorice Extract on Oxytocin-Induced Uterine Contraction through Inhibiting the Phosphorylation of Heat Shock Protein 27.

Licorice derived from the roots and rhizomes of Glycyrrhiza uralensis Fisch. (Fabaceae), is one of the most widely-used traditional herbal medicines in China. It has been reported to possess significant analgesic activity for treating spastic pain. The aim of this study is to investigate the spasmolytic molecular mechanism of licorice on oxytocin-induced uterine contractions and predict the relevant bioactive constituents in the aqueous extract. The aqueous extraction from licorice inhibited the amplitude and frequency of uterine contraction in a concentration-dependent manner. A morphological examination showed that myometrial smooth muscle cells of oxytocin-stimulated group were oval-shaped and arranged irregularly, while those with a single centrally located nucleus of control and licorice-treated groups were fusiform and arranged orderly. The percentage of phosphorylation of HSP27 at Ser-15 residue increased up to 50.33% at 60 min after oxytocin stimulation. Furthermore, this increase was significantly suppressed by licorice treatment at the concentration of 0.2 and 0.4 mg/mL. Colocalization between HSP27 and α-SMA was observed in the myometrial tissues, especially along the actin bundles in the oxytocin-stimulated group. On the contrary, the colocalization was no longer shown after treatment with licorice. Additionally, employing ChemGPS-NP provided support for a preliminary assignment of liquiritigenin and isoliquiritigenin as protein kinase C (PKC) inhibitors in addition to liquiritigenin, isoliquiritigenin, liquiritin and isoliquiritin as MAPK-activated protein kinase 2 (MK2) inhibitors. These assigned compounds were docked with corresponding crystal structures of respective proteins with negative and low binding energy, which indicated a high affinity and tight binding capacity for the active site of the kinases. These results suggest that licorice exerts its spasmolytic effect through inhibiting the phosphorylation of HSP27 to alter the interaction between HSP27 and actin. Furthermore, our results provide support for the prediction that potential bioactive constituents from aqueous licorice extract inhibit the relevant up-stream kinases that phosphorylate HSP27.