Development of a murine model of ischemic osteonecrosis to study the effects of aging on bone repair

Abstract

Age at onset is one of the most important predictors of outcome following ischemic osteonecrosis (ON). Currently, there is no well‐established animal model to study the effects of age on the repair process following ischemic ON. The purpose of this study was to further advance a murine model of ischemic ON using four age groups of mice to determine the effects of aging on revascularization and bone repair following ischemic ON. Ischemia was surgically induced in the distal femoral epiphysis of four age groups of skeletally immature and mature mice; juvenile (5 weeks), adolescent (12 weeks), adult (22 weeks), and middle age (52 weeks). Mice were euthanized at 2 days or 4 weeks post‐ischemia surgery to evaluate the extent of ON, revascularization, and bone repair. Terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labeling staining showed extensive cell death in the epiphysis of all four age groups at 2 days post‐ischemia surgery. At 4 weeks, the juvenile mice followed by the adolescent mice had significantly greater revascularization and repair of the necrotic marrow space, increased osteoblast and osteoclast numbers, and increased bone formation rates compared to the adult and middle‐age mice. Faster revascularization and bone healing were observed in the skeletally immature mice compared to the skeletally mature mice following ischemic ON. The findings resemble the clinical observation of aging on bone repair following ischemic ON. The mouse model may serve as a useful tool to investigate the mechanisms underlying the age‐related impairment of bone repair in adolescent and adult ON and to develop novel therapeutic strategies.

Biochanin A inhibits endothelial dysfunction induced by IL‑6‑stimulated endothelial microparticles in Perthes disease via the NFκB pathway

“…In young animal models, Perthes disease may be induced through the ischemic osteonecrosis of the femoral head by ligation of the femoral neck. Yamaguchi et al ( 62 ) showed that in piglets, a model of ischemic osteonecrosis of the femoral head can be constructed by ligating the femoral neck, cutting off the round ligament, and implementing supra knee amputation at the junction of the distal epiphysis and epiphysis of the femur. In this model, the IL-6 receptor monoclonal antibody can reduce hip synovitis and osteoclast bone resorption, and increase bone formation.…”

A Review of Rat Models of Avascular Necrosis of the Femoral Head Treated with Natural Extracts

“…Rat models of steroid induction of ANFH under hypoxic conditions [46], surgical induction of ANFH considering ageing and bone repair [47], and ANFH induction caused by tobacco smoke [48] have been reported since 2020. By using the appropriate rat model for the induction of ANFH which suits the disease characteristics (mechanism, purpose of study, and bone condition) of interest, the relevant mechanisms of action can be studied in the future.…”

Interleukin-6 receptor blockade improves bone healing following ischemic osteonecrosis in adolescent mice

“…The sample size was calculated to obtain 80% power with alpha ​= ​0.05 and large effect-size (i.e., Cohen's d ​> ​0.8–0.9) based on our previous study [ 10 ]. JIO was surgically induced on the distal femoral epiphysis under isoflurane anesthesia, as previously described [ 22 , 23 ]; this model produced almost 100% ON in immature [ 22 ] and adolescent mice [ 23 ]. Briefly, the blood vessels supplying the right distal femoral epiphysis (i.e., a branch of the popliteal vessel and branches of the medial, central, and lateral genicular vessels) were identified and cauterized.…”

“…The distal femoral epiphyses were fixed with 10% formalin, decalcified in 10% EDTA for 5 days, embedded in paraffin, cut into 5 ​μm sections, and stained [ 9 , 22 , 23 ]. H&E staining was performed according to a standard protocol [2 weeks (saline; n ​= ​7, MR16-1; n ​= ​8), 4 weeks (saline; n ​= ​13, MR16-1; n ​= ​15)] ( Table 1 ).…”