Persistent Abnormal Immunocytes Induced Systemic Bone Loss in Locally Irradiated Rats

Area of Science:

• Oncology
• Immunology
• Bone Biology

Background:

• Radiotherapy often leads to chronic and systemic bone complications.
• The underlying pathological mechanisms for these bone complications are not fully understood.

Purpose of the Study:

• To investigate persistent, systemic changes in locally irradiated rats.
• To identify systemic pathological changes affecting bone metabolism post-irradiation.

Main Methods:

• Assessed inflammatory and oxidative stress markers.
• Analyzed lymphocyte populations (B and T cells) using flow cytometry.
• Evaluated bone marrow-derived mesenchymal stem cells (BMSCs) proliferation, apoptosis, and differentiation potential.

Main Results:

• No significant systemic inflammatory or oxidative stress changes were observed.
• Sustained increases in B lymphocytes and altered T lymphocyte levels (decreased CD4+/CD8+ ratio) were noted.
• Irradiated rat lymphocytes inhibited normal BMSC proliferation and osteogenic differentiation while promoting adipogenesis.

Conclusions:

• Altered lymphocyte levels post-radiotherapy contribute to chronic bone complications.
• This occurs by suppressing BMSC proliferation and osteoblastogenesis, potentially favoring adipogenesis.