en عمومى General گزارش مورد case report <p><strong>Background:</strong> Exposure to an increasing amount of extremely low-frequency magnetic fields (MFs) causes some adverse effects. Considering a direct association between the sizes and numbers of argyrophilic nucleolar organizer regions (AgNORs) and cell proliferation, this study was conducted to evaluate the effect of 50-Hz MFs on the AgNORs of bone marrow (BM) cells.</p> <p><strong>Methods:</strong> Eighty male rats were randomly divided into four exposed groups and one control group. The exposed groups received 50-Hz MFs with magnetic flux densities of 1, 100, 500, and 2000 &micro;T two hours a day for two months. BM cells were aspirated from sacrificed rats&rsquo; femoral bones, smeared on glass slides, and then stained with silver nitrate for AgNORs. The area (AA), length (AL), and number (AN) of AgNORs were calculated by a microscope equipped with a camera and Scion Image software in 100 BM cells of each rat. The mean of AA, AL, and AN was computed for each group.</p> <p><strong>Results:</strong> AA, AL, and AN significantly reduced in the 1 &micro;T group compared with 2000 &micro;T and control groups. Eventually, there was a nonlinear relationship between the effect of 50-Hz MFs and magnetic flux densities.</p> <p><strong>Conclusion:</strong> Overall, 50-Hz MFs with a magnetic flux density of 1 &micro;T reduced AgNORs in BM cells. However, 100, 500, and 2000 &micro;T did not affect AgNORs. Therefore, 50-Hz MFs with low density may suppress BM cell proliferation.</p> Bone marrow, Argyrophilic nucleolar organizer regions, Magnetic fields 20 24 http://ajpr1.umsha.ac.ir/browse.php?a_code=A-10-2-42&slc_lang=en&sid=1 Mohammad Rafiee 1003194753284600218 1003194753284600218 Yes Department of Medical Laboratory Sciences, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, Iran Mohammad Abbasi 1003194753284600219 1003194753284600219 No Department of Internal Medicine, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Mohammad Yousef Alikhani 1003194753284600220 1003194753284600220 No Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Safoora Nikzad 1003194753284600221 1003194753284600221 No Department of Medical Physics, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Alireza Zamani 1003194753284600222 1003194753284600222 No Department of Immunology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran