Abstract Objective To investigate the influence of renin angiotensin (RAS) biaxial on patients with ischemic necrosis of the femoral head (INFH). Methods From October 2015 to June 2017, 90 patients underwent femoral head replacement in the Department of Orthopedics in Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology and Suizhou Central Hospital in Hubei Province were selected. Among them, 45 patients with INFH were served as INFH group, and 45 patients with postoperative traumatic femoral neck fracture were served as control group. The expressions of angiotensin converting enzyme (ACE), angiotensin Ⅱ (Ang Ⅱ), angiotensin Ⅱ-1 receptor (AT1R), ACE2, Ang (1-7), Mas receptor (Mas-R) in the circulating blood of two groups were detected before operation, and the expressions of ACE, AngⅡ, AT1R, ACE2, Mas-R, receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) mRNA in local bone tissue of femoral head were detected after operation, and immunohistochemical analysis was performed. Results There were no significant differences in the expressions of ACE, AngⅡ, AT1R, ACE2, Ang(1-7) and Mas-R between two groups (P > 0.05). The mRNA expression levels of ACE2, Mas-R and OPG in local bone tissue of femoral head in INFH group were lower than those in control group (P < 0.05), while the mRNA expression levels of ACE, AngⅡ, AT1R, RANKL and RANKL mRNA/OPG mRNA were higher in INFH group than those in control group (P < 0.05). Compared with control group, HE staining of bone tissue in INFH group showed hyperplasia of adipocytes, thinning of bone trabeculae, pyknosis and deep staining of bone nucleus, and obvious increase of empty bone lacunae; Masson staining of bone tissue in INFH group showed that dark blue became lighter and more disordered, showing the decrease of collagen structure and obvious hyperplasia of fibrous structure. The results of immunohistochemistry showed that the expressions of ACE and AT1R were higher in INFH group than those in control group, while the expressions of ACE2 and Mas-R were lower than those of control group. There were significant differences in the percentage of positive expression area of ACE, AT1R, ACE2 and Mas-R between two groups (P < 0.05). Conclusion Some components of RAS biaxial in local bone tissue of INFH patients are abnormally expressed, which may be involved in the process of local bone turnover and osteonecrosis, providing new ideas for the follow-up study and diagnosis and treatment.
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