Persistent Abnormal Immunocytes Induced Systemic Bone Loss in Locally Irradiated Rats

This study aimed to observe persistent and systemic changes in locally irradiated rats and to determine the systemic pathological changes that persistently affect bone metabolism. We examined the inflammatory and oxidative stress responses that occurred after local irradiation using enzyme immunoassays and biochemical analyses. Lymphocytes obtained from the blood, spleen, thymus, and bone marrow were evaluated using flow cytometry. The proliferation and apoptosis characteristics of co-cultured bone marrow-derived mesenchymal stem cells (BMSCs) were detected by MTT assay and PI/Annexin V-FITC staining, respectively, and the differentiation of BMSCs was measured according to alkaline phosphatase (ALP) staining, alizarin red staining, and Oil Red O staining and by evaluating the mRNA expression of ALP, osteocalcin (OCN), osteopontin (OPN), collagen I, Runx2, and PPAR γ. Our results revealed that no significant or continuous differences were present in the inflammatory response or the oxidative stress response throughout the body after local irradiation. B lymphocyte levels increased continuously in the blood, spleen, and bone marrow after local irradiation. T l ymphocyte levels were decreased at 2 weeks after local irradiation, and CD8+T lymphocyte levels were increased in the blood, thymus, and bone marrow at 12  weeks after local irradiation. The ratio of CD4+/CD8+T lymphocytes began to decrease during the early phase after local irradiation and became significantly decreas...
Source: Calcified Tissue International - Category: Orthopaedics Source Type: research