OBJECTIVETo study the role of hypoxia-inducible factor 1 alpha (HIF1alpha) on knee cartilage degeneration,and to explore the effects and mechanisms of Chinese herbal compound Yiqi Huayu prescription on HIF-1alpha gene knockout mice on knee cartilage degeneration.

METHODSThe 4-month and 6-month HIF-1alpha gene knock out mice were obtained by interbreeding, and divided into HIF-1alpha +/+ 4-month mice group,HIF-1alpha -/- 4-month mice group,HIF-1alpha +/+ 6-month mice group and HIF-1alpha -/- 6-month mice group, 3 mice in each group. And then the 2-month-old HIF-1alpha gene knock out mice were randomly divided into Yiqi Huayu prescription group and physiological saline group. There were 6 mice in each group. After 2 months' drug administration, the knee joint of mice was collected, and the Mankin score were evaluated; Safranine-fast green staining, HE Staining, and immunohistochemistry analysis for VEGF, Col X, Col II, MMP-13 and Sox-9 were performed erespectively.

RESULTS(1) Compared to the results in the HIF-1alpha+/+ mice groups, the HIF-1alpha-/- mice developed aging related cartilage loss and bony tissue appearance, cartilage defects increased,and cells reduced. In HIF-1alpha-/-4-month mice and 6-month mice group, the expresion of Col II and Sox9 decreased, and the expression of Col X, MMP-13 and VEGF increased. (2) Compared to the physiological saline group, the ossification and defect of knee joint cartilage reduced of mice in the Yiqi Huayu prescription group, the cartilage cell distribution was more uniform, and the total number of cells increased. The expression of type II collagen and Sox9 protein increased, expression of Col X, MMP-13 and VEGF protein decreased of mice in the Yiqi Huayu prescription group.

CONCLUSIONThe knee cartilage degenerates in the HIF-1alpha cKO mice, and the degeneration increased with age adding. The Yiqi Huayu prescription can delay the degeneration of knee cartilage of HIF-1alpha cKO mice.