en Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;"><span style="font-size:10pt"><span style="text-justify:newspaper"><span style="text-kashida-space:50%"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:black"><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Background</span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-weight:bold"><span style="language:en-US">:</span></span></span></span></span> <span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">The efficacy of low-dose rate ionizing radiation (LDRIR) for anti-inflammatory treatment has been confirmed in various clinical studies. However, the radiobiological mechanisms involved in the anti-inflammatory action of LDRIR have not been completely elucidated. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Materials and Methods:</span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US"> This study investigated whether LDRIR at 0.5 or 1 Gy affected the regulation of cytokine messenger RNA expression and protein levels in inflamed synoviocytes and chondrocytes induced by lipopolysaccharide. Intercellular adhesion molecule-1, interleukin-6, interleukin-8, and growth-regulated alpha protein expression were analyzed in synoviocytes and chondrocytes at 24 h after lipopolysaccharide treatment using reverse transcription polymerase chain reaction, immunostaining, Western blotting, and enzyme-linked immunosorbent assays. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Results: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">The messenger RNA expression levels of interleukin-6, interleukin-8, and growth-regulated alpha protein were lower in synoviocytes cotreated with lipopolysaccharide and 0.5 or 1 Gy radiation than in those treated with lipopolysaccharide alone. The immunostaining results showed that all target cytokines were downregulated after 0.5 and 1 Gy of radiation in inflamed synoviocytes and chondrocytes. In chondrocytes, all four cytokines were significantly downregulated at a dose rate of 0.053 Gy/min, and the extent of regulation was similar to that at 4.02 Gy/min. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Conclusion:</span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US"> Our findings indicate that LDRIR may regulate pro-inflammatory cytokine expression in both synoviocytes and chondrocytes, regardless of the dose rate. Therefore, LDRIR can alleviate concerns of carcinogenesis and may be useful in clinical settings.</span></span></span></span></span></span></span></span></span></div> low-dose radiotherapy, anti-inflammation, synoviocytes, chondrocytes, pro-inflammatory cytokines. 585 593 http://ijrr.com/browse.php?a_code=A-10-1-1213&slc_lang=en&sid=1 S. Song 7900319475328460027908 7900319475328460027908 No Department of Radiation Oncology, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea Y. Song Lee 7900319475328460027909 7900319475328460027909 No Research Center, Dongnam Institute of Radiological and Medical Science, 40 Jwadong-gil, Jangan-eup, Gijang-gun, Busan 46033, Republic of Korea W. Kim 7900319475328460027910 7900319475328460027910 No Research Center, Dongnam Institute of Radiological and Medical Science, 40 Jwadong-gil, Jangan-eup, Gijang-gun, Busan 46033, Republic of Korea M. Choi 7900319475328460027911 7900319475328460027911 No Research Institute of Convergence of Biomedical Science and Technology, Yangsan Hospital Pusan National University, Busan 50612, Republic of Korea S. Kim 7900319475328460027912 7900319475328460027912 No Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, 37, Nakdong-daero 550 Beon-gil, Saha-gu, Busan 49315, Republic of Korea H. Bae 7900319475328460027913 7900319475328460027913 No Department of Orthopedic Surgery, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea H. Han 7900319475328460027914 7900319475328460027914 No Department of Orthopedic Surgery, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea T. Yu tosolyu@naver.com 7900319475328460027915 7900319475328460027915 Yes Department of Radiation Oncology, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea T.G. Son 7900319475328460027916 7900319475328460027916 No Research Center, Dongnam Institute of Radiological and Medical Science, 40 Jwadong-gil, Jangan-eup, Gijang-gun, Busan 46033, Republic of Korea