Mechanisms of Wenjing Huayu Zhitong Therapy for Primary Dysmenorrhea with Cold Coagulation and Blood Stasis Syndrome Based on MAPK/ERK Signaling Pathway / 中国实验方剂学杂志

Objective:To study the effect of Wenjing Huayu Zhitong therapy （Xiangyan Zhitong prescription， XZP） on the mitogen activated protein kinase （MAPK）/extracelluar regulated protein kinase （ERK） signaling pathway of primary dysmenorrhea （PD） rats， and explore the pathogenesis of PD and the mechanism of action of Wenjing Huayu Zhitong therapy. Method:Forty-eight female SPF-grade Wistar rats were randomly divided into blank group，model group， western medicine group， low-dose XZP group， medium-dose XZP group， and high-dose XZP group， with 8 rats in each group. In addition to the blank group， dysmenorrhea rat model with cold coagulation and blood stasis syndrome was established by cold stimulation combined with estradiol benzoate and oxytocin. The rats in the blank group，model group，western medicine group， low-dose XZP group， medium-dose XZP group， and high-dose XZP group were given distilled water， distilled water，0.06 g·kg^-1 ibuprofen， 6.55 g·kg^-1 XZP， 13.09 g·kg^-1 XZP， and 26.18 g·kg^-1 XZP， respectively， by gavage for 6 days. The writhing latency and writhing frequency of rats were recorded within 30 min after oxytocin injection.Western blot was used to detect the protein expression of B-Raf， mitogen activates extracellular regulated kinases1/2 （MEK1/2）， extracellular regulated kinases1/2 （ERK1/2）， p-MEK1/2， p-ERK1/2， c-Jun， and cyclooxygenase-2 （COX-2） in rat uterus. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was employed to detect the mRNA expression of B-Raf， MEK1， MEK2， ERK1， ERK2， c-Jun， and cyclooxygenase-2 （COX-2） in rat uterus. Result:Compared with the model group，the treatment groups showed insignificantly prolonged writhing latency and significantly reduced writhing frequency （<italic>P</italic><0.01）. On the 6^th day of modeling， there was no significant difference in the quantitative scores of symptoms and signs among the treatment groups. On the 12^th day of modeling， the scores changed little in the western medicine group and the low-dose XZP group and decreased significantly in the medium- and high-dose XZP groups （<italic>P</italic><0.01） compared with those in the model group. Compared with those in the blank group， the protein and mRNA levels of p-MEK1/2， p-ERK， B-Raf， c-Jun， and COX-2 in the model group were significantly up-regulated （<italic>P</italic><0.01）. Compared with those in the model group， the protein and mRNA levels of p-MEK1/2， p-ERK1/2， B-Raf， c-Jun， and COX-2 in the western medicine group， medium-dose XZP group， and high-dose XZP group were significantly down-regulated （<italic>P</italic><0.05，<italic>P</italic><0.01）. Conclusion:The mechanism of Wenjing Huayu Zhitong therapy in treating PD with cold coagulation and blood stasis syndrome may be related to the down-regulation of MAPK/ERK signaling pathway.