Estrogen alleviates post-traumatic osteoarthritis progression and decreases p-EGFR levels in female mouse cartilage

Objective To investigate the effect of estrogen on the progression of post-traumatic osteoarthritis (PTOA) in mice and its possible mechanism. Methods Twelve-week-old ICR mice were divided into Group A (female control group), group B (ovariectomized(OVX) group), group C (OVX group supplemented with estrogen), and group D (male group) by destabilization of the medial meniscus (DMM)or sham operation. Safranin O staining was performed at 8 weeks and 12 weeks after operation, and the degree of articular cartilage lesion was evaluated using Mankin score. Twelve weeks after the operation, tissue sections were stained to analyze the matrix metalloproteinase 13(MMP13), phosphorylated epidermal growth factor receptor (p-EGFR) expression and apoptosis of chondrocytes. Results Decreased estrogen can significantly increase the weight of mice in female mice. The degree of cartilage damage in the knee joint on the DMM side of female mice was significantly severer than that on the Sham side. The DMM side also showed higher MMP13 expression and increased apoptotic chondrocytes. The degree of cartilage damage in the knee joint on the DMM side of female mice was significantly reduced after estrogen supplementation, and cartilage damage in the knee joint on the DMM side of female mice was less serious than that of male mice. As estrogen levels decreased, the severity of cartilage erosion in the knee joint on the DMM side was aggravated, and p-EGFR expression in the cartilage surface was also higher in female mice contrast to that in male mice. However, minimal changes in p-EGFR expression in the cartilage surface of bilateral knee joints of male mice were observe. Conclusion Estrogen has a regulatory effect on PTOA and its inhibits the expression of p-EGFR in cartilage on the knee joint surface and has a protective effect on articular cartilage in female mice.

Automated summary

This study aimed to investigate the effect of estrogen on the progression of post-traumatic osteoarthritis (PTOA) in mice and its possible mechanism. The results showed that decreased estrogen can aggravate the weight of female mice, and the degree of cartilage damage in the knee joint on the traumatized side was more severe. Estrogen supplementation can reduce cartilage damage in the knee joint on the traumatized side of female mice, and the damage is less serious than that of male mice. Moreover, as estrogen levels decreased, the severity of cartilage erosion on the traumatized side worsened, and the expression of p-EGFR in the cartilage surface was higher in female mice.