Expression of α2-macroglobulin in steroid-induced femoral head necrosis at different phases

Abstract

Objective To discuss the relationship between α2-macroglobulin (α2M) and steroid-induced femoral head necrosis at different phases. Methods The patients with femoral head necrosis and proximal femoral fracture were randomly selected. They were randomly divided into five groups according to association research circulation osseous (ARCO) stages of femoral head necrosis, including control group, experimental groups Ⅰ-Ⅳ, n=20 in each group and 100 in all. Histopathology, immunohistochemistry, and real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) were used to compare the expression levels of α2M in different tissues of each group. Results (1) Histopathologically, the rate of empty bone depression in the experimental groups Ⅰ-Ⅳ [(15.66±2.76)%, (28.29±1.38)%, (39.43±5.47)% and (51.27±4.85)%] was significantly higher than that in control group [(8.54±3.25)%], and the differences between each experimental group and control group were statistically significant (P=0.000, 0.000, 0.008, 0.010); (2) Immunohistochemically, the expression of α2M in the control group (1.88±0.22) was significantly higher than that in he experimental groups Ⅰ-Ⅳ (1.24±0.16, 1.17±0.19, 0.73±0.11 and 0.26±0.09 respectively), and the difference was statistically significant (P=0.000, 0.000, 0.001, 0.009); (3) For FQ-PCR, the mRNA expression level of α2M in the articular capsule synovial membrane of control group (18.67±2.37) was significantly higher than that in experimental groups Ⅱ-Ⅳ (13.67±1.87, 7.59±1.01 and 4.89±0.54), and the difference was statistically significant (P=0.000, 0.000, 0.000); The mRNA expression level of α2M in the joint fluid was significantly lower in the experimental groups Ⅰ-Ⅳ (13.26±1.06, 12.78±1.98, 4.56±0.89 and 3.34±0.56) than that in the control group (17.87±2.26), and the difference was statistically significant (P=0.000, 0.000, 0.000, 0.000); The mRNA expression level of α2M in the femoral head was significantly higher in the control group (16.56±2.18) than that in the experimental groups Ⅰ-Ⅳ (13.01±1.06, 10.76±1.93, 3.76±0.96 and 1.34±0.56), and the difference was statistically significant (P=0.000, 0.000, 0.000, 0.000). Conclusion α2M can play an important role in the different phases and different tissues of steroid-induced femoral head necrosis. Key words: α2-macroglobulin; Steroid; Femoral head necrosis; Early diagnosis