Affiliation:
1. Department of Trauma Surgery Hannover Medical School Carl‐Neuberg‐Str. 1 30625 Hannover Germany
2. Department of Spine Surgery Yu Huang Ding Hospital Yu Dong Str. 20 Yan Tai 264000 China
3. Ulm University Medical Center Department of Trauma Hand, Plastic and Reconstructive Surgery Translational and Experimental Trauma Research Helmholtz Str. 16 89081 Ulm Germany
Abstract
AbstractClinical complications frequently follow polytrauma and bleeding fractures, increasing the risk of delayed fracture healing and nonunions, especially in aged patients. Therefore, this study examines age's impact on fracture repair with and without severe bleeding in mice. Young (17–26 weeks) and aged (64–72 weeks) male C57BL/6J mice (n = 72 in total, n = 6 per group) are allocated into 3 groups: the fracture group (Fx) undergoes femur osteotomy stabilized via external fixator, the combined trauma group (THFx) additionally receives pressure‐controlled trauma hemorrhage (TH) and Sham animals are implanted with catheter and fixator without blood loss or osteotomy. Femoral bones are evaluated histologically 24 h and 3 weeks post‐trauma, while RANKL/OPG and β‐CTx are measured systemically via ELISA after 3 weeks. Aging results in less mineralized bone and fewer osteoclasts within the fracture of aged mice in contrast to young groups after three weeks. Systemically, aged animals exhibit increased RANKL and OPG levels after fracture compared to their young counterparts. The RANKL/OPG ratio rises in aged Fx animals compared to young mice, with a similar trend in THFx groups. In conclusion, age has an effect during the later course of fracture healing on the cellular and systemic levels.