Protective effects of α‑2‑macroglobulin on human bone marrow mesenchymal stem cells in radiation injury

Abstract

Osteoradionecrosis of the jaws (ORNJ) is a complication of oral and maxillofacial malignancy that arises following radiotherapy; progressive jaw necrosis severely decreases the quality of life of patients. Human bone marrow mesenchymal stem cells (hBMMSCs) are a cell type with self-renewal and pluripotent differentiation potential in the bone marrow stroma. These cells are associated with bone tissue regeneration and are one of the primary cell types affected by bone tissue radiation injury. α-2-macroglobulin (α2M) is a glycoprotein-rich macromolecule that interacts with cytokines, growth factors and hormones to serve a variety of biological roles. In addition, α2M possesses radio-protective effects. The aim of the present study was to investigate whether α2M has protective effects against radiation injury of hBMMSCs. Cell counting kit-8 and colony formation assays were used to monitor cell proliferation. Western blot analysis and reverse transcription-quantitative polymerase chain reaction were used to detect Beclin1, microtubule-associated protein 1A/1B, sex determining region Y, Nanog, runt-related transcription factor 2, osteoglycin and manganese superoxide dismutase expression. The formation of calcium nodules was evaluated by Alizarin red staining after osteogenic induction. Flow cytometric analysis of Annexin-V and propidium iodide double staining was used to detect changes in apoptosis rate. Alkaline phosphatase and superoxide dismutase activity were determined using colorimetric assays. Reactive oxygen species levels were detected using 2′,7′-dichlorodihydrofluorescein diacetate. The results of the present study revealed that α2M increased the rate of proliferation, reduced autophagy, alleviated pluripotent differentiation injury, increased the osteogenic differentiation ability and decreased the rate of apoptosis in hBMMSCs following irradiation via an antioxidative pathway. In conclusion, α2M exhibited protective effects against radiation injury in hBMMSCs and may be considered a potential therapeutic agent for the prevention and treatment of ORNJ.

Protective role of α2‐macroglobulin against jaw osteoradionecrosis in a preclinical rat model

“…Our previous study found that there was a positive correlation between serum α2M levels and the dose of radiotherapy in patients with nasopharyngeal carcinoma. In addition, we also found that α2M protected the osteogenic potential of bone marrow mesenchymal stem cells after radiation . Therefore, we hypothesized that α2M may be able to protect against jaw ORN.…”

“…In addition, we also found that α2M protected the osteogenic potential of bone marrow mesenchymal stem cells after radiation. 11 Therefore, we hypothesized that α2M may be able to protect against jaw ORN.…”

Effect of α2‑macroglobulin in the early stage of jaw osteoradionecrosis

“…In addition, a previous study reported that the rat acute-phase α2M protein serves a central role in amifostine-mediated radioprotection, increasing the protective effect by 45-fold (19). As demonstrated in a study from our laboratory, α2M maintains the osteogenic potential of human bone marrow mesenchymal stem cells (hBMMSCs) following IR (20). In particular, hBMMSCs are among the main cells damaged during bone tissue radiation (21,22).…”

“…Improved 3D-printed mandible fixtures and a lead sheet were used to precisely deliver radiation to the mandible and protect the surrounding tissues by shielding them from IR. The dosage was based on an extensive review of the literature (25,26) and previous work from our laboratory (20). All rats were fed a liquid diet during the first week after IR.…”

“…7501; ScienCell Research Laboratories, Inc.) supplemented with 1% mesenchymal stem cell growth supplement (ScienCell Research Laboratories, Inc.), 1% penicillin/streptomycin solution (ScienCell Research Laboratories, Inc.) and 5% fetal bovine serum (ScienCell Research Laboratories, Inc.) and placed in a humidified 5% CO 2 incubator at 37˚C. Cells were seeded in 96-well plates at a density of 5x10 3 cells/well (6 duplicate wells per group) and were divided into four groups: Control group, no treatment; α2M group, 0.5 mg/ml α2M pretreatment for 24 h with no irradiation; RT group, no α2M pretreatment + irradiation with 8 Gy; and α2M + RT group, 0.5 mg/ml α2M pretreatment for 24 h + one dose of 8 Gy dose irradiation (20). After cell treatment for 24, 48 and 72 h, 10 µl of the Cell Counting Kit-8 solution (CCK-8; cat.…”