ABSTRACT
<p><b>OBJECTIVE</b>To investigate the mRNA expression of severe acute respiratory syndrome-associated coronavirus (SARS-COV) functional receptor, angiotensin-converting enzyme 2 (ACE2), in human femoral head and conjunctiva, and explore the possible entry route of SARS-COV in human femoral head.</p><p><b>METHODS</b>ACE2 mRNA in human femoral head was detected by nested RT-PCR with human beta actin gene as the positive control.</p><p><b>RESULTS</b>The mRNA of human beta actin gene could be amplified efficiently in all the tissue samples. The mRNA of human ACE2 was expressed efficiently in the normal lung tissue, but not in the cartilage and cancellous bone under the weight-bearing area of the femoral head.</p><p><b>CONCLUSION</b>SARS-COV can not infect the femoral head tissue and lead to avascular necrosis of the femoral head directly by the spike glycoprotein, and mechanism of the virus for causing avascular necrosis needs further investigation.</p>