Positive effect of IGF‐1 injection on gastrocnemius of rat during distraction osteogenesis

Abstract

Distraction osteogenesis (DO) is used to form new bone between bone segments to lengthen the callus. Skeletal muscles frequently fail to adapt to distraction, which causes complications. Insulin-like growth factor-1 (IGF-1) has been implicated as a central regulator of muscle repair. We hypothesized that IGF-1 injection could reduce muscle complications in DO. A total of 102 SpragueDawley rats received DO or did not were randomly assigned into saline, IGF-1 and normal groups. On the day before the distraction, the rats in the IGF-1 group were injected with IGF-1. The gastrocnemius muscles of the rats were harvested at the 0, 1st, 4th, 7th, and 10th days of distraction. The weight of the muscles, cross-sectional area (CSA) of the muscle fibers, collagen volume fraction (CVF), maximum limit load (MLL), maximum contraction forces, and gene expression of Akt, MyoD, myogenin, myostatin, and collagen I were analyzed. The results indicated that IGF-1 injection had increased the weights, CSA of the muscle fibers, MLL and force generation of the gastrocnemius. Also, Akt, MyoD, and myogenin were upregulated, and myostatin was downregulated in the IGF-1 group. Injection of IGF-1 could attenuate the gastrocnemius atrophy, prevent fibrosis, increase MLL, and regulate the related mRNA. ß

Biomechanic and histologic analysis of fibroblastic effects of tendon-to-bone healing by transforming growth factor β1 (TGF-β1) in rotator cuff tears

“…Overall, our results suggested that administration of TGF-β1 alters the loose connective tissue inflammatory process by increasing extra-cellular matrix homeostasis activity so as to accelerate healing. Klein et al [22][23] demonstrated that macrophage infiltration and degeneration accompanied by increased IGF-1 and VEGF expression in a rat model of massive rotator cuff tears did not negatively affect outcomes. Compared to previous studies in our research, it was found that the rate of expression of IGF-1 and VEGF reached rapidity at 16 weeks, which may be at the peak of secretion.…”

The Role of IGF-1 Signaling in Skeletal Muscle Atrophy

“…Moreover, IGF-1 has been shown to increase transcription rate of α-skeletal actin during differentiation and myosin heavy chain (MHC) IIB in C2C12 myoblasts and myotubes, respectively [30,31]. Increased transcription by IGF-1 may be regulated by myogenin and MyoD, which are both transcription factors involved in the expression of actin and myosin, since IGF-1 has been shown to induce myogenin and MyoD expression [32] and both transcription factors increase in the human vastus lateralis after resistance exercise [33]. Note, myogenin has been shown to be stimulated by IGF-1/PI3K/Akt signaling when simultaneously MAPK signaling is inhibited [24,34].…”

IGF-1 polymorphisms modulate the susceptibility to osteonecrosis of the femoral head among Chinese Han population

“…[14] Taken together, IGF-1 plays critical roles in osteogenesis, bone restoration, and bone regeneration. [15] Animal experiments demonstrated that after treatment, the levels of IGF-1 were significantly increased in ONFH rabbit model, revealing the close association of IGF-1 expression with ONFH development. [16] IGF-1 , the encoding gene for this factor, is located at chromosome 12q23.2, and some of functional polymorphisms in this gene have been reported to be associated with production of IGF-1 .…”