Effect of whole body vibration on HIF-2α expression in SD rats with early knee osteoarthritis.

Abstract

To investigate the effect of different frequencies of whole body vibration (WBV) on articular cartilage of early knee osteoarthritis (OA) rats and determine whether WBV would influence the pathway of hypoxia-inducible factor-2α (HIF-2α) regulation-related genes after 8weeks of treatment. Forty 8-week-old OA rats were divided into five groups: sham control (SC); high frequency 60Hz (HV1); high frequency 40Hz (HV2); middle frequency 20Hz (MV) and low frequency 10Hz (LV). WBV (0.3g) treatment was given 40min/day and 5days/week. After 8weeks, rats were killed and knees were harvested. OA grading score: Osteoarthritis Research Society International (OARSI), and the expression of related genes: interleukin-1β (IL-1β), HIF-2α, matrix metalloproteinases-13 (MMP-13), and collagen type II alpha 1 (COL2A1), at both mRNA and protein levels were analyzed. After 8weeks of WBV, our data showed that lower frequency (10Hz) was more effective than the higher ones, yet they all suggested that WBV alleviates the erosion of knee articular cartilage in early OA. The expression of IL-1β, HIF-2α and MMP-13 decreased with frequency and reached the lowest level at 10Hz, the expression of COL2A1 increased with frequency and reached the highest level at 10Hz. This study demonstrates that WBV could alleviate the degeneration of knee joints in an early OA rat model. WBV regulates related gene expression at both mRNA and protein levels. HIF-2α could be a therapeutic target. The effect of WBV is frequency dependent; the lower frequency shows better effects.