ABSTRACT
Objective:To investigate the effect of shikonin on uterine leiomyoma in rats and its molecular mechanism. Method:Sixty female SD rats， of SPF grade and weighing 200-250 g， were randomly divided into the control group， model group， low-， medium-， and high-dose （5， 10， 20 mg·kg<sup>-1</sup>） shikonin groups， and mifepristone group. A rat model of uterine leiomyoma was established， and the changes in uterine wet weight， uterine coefficient， and smooth muscle thickness were detected after drug administration for four successive weeks. The pathological changes in uterine tissue were observed by hematoxylin-eosin （HE） staining. The contents of estrogen receptor （ER） and progesterone receptor （PR） in serum and uterus were measured by enzyme-linked immunosorbent assay （ELISA）， and the protein expression levels of ER， PR， phosphorylated extracellular signal-regulated kinase （p-ERK）， and ERK in the uterine tissue were assayed by Western blot. Result:Compared with the control group， the model group exhibited significantly increased uterine wet weight， uterine coefficient， and smooth muscle thickness （<italic>P</italic><0.01）， uterus deformity， focal smooth muscle cell necrosis and hyperplasia， neutrophil infiltration. elevated serum and uterine ER and PR （<italic>P</italic><0.01）， and up-regulated p-ERK protein expression in the uterine tissue （<italic>P</italic><0.01）. Compared with the model group， shikonin at the middle and high doses and mifepristone significantly reduced the uterine wet weight， uterine coefficient， and smooth muscle thickness （<italic>P</italic><0.01）， relieved the pathological changes in uterus，and lowered serum and uterine ER and PR， and down-regulated the p-ERK protein expression in the uterine tissue （<italic>P</italic><0.05）. In addition， the uterine wet weight， smooth muscle thickness， serum ER， and uterine PR and p-ERK protein expression in the low-dose shikonin group were significantly lower than those in the model group （<italic>P</italic><0.05）. Conclusion:Shikonin produces the anti-uterine leiomyoma activity possibly by inhibiting the activation of ERK pathway.