Exploring the Potential Role of Dexmedetomidine in Reducing Postoperative Cognitive Dysfunction in Elderly Hip Fracture Patients

Background: Hip fractures are prevalent in the elderly; however, Postoperative Cognitive Dysfunction (POCD) is a possible complication of hip fracture surgery in elderly patients. This study examines the influence and the underlying mechanism of dexmedetomidine on POCD in elderly patients following hip fracture surgery. Methods: The retrospective study involved elderly patients with hip fracture who were treated at the Fifth Affiliated Hospital of Xinjiang Medical University from October 2021 to August 2022. During the surgery procedures, dexmedetomidine was administrated and the peripheral blood samples were collected from the patients. Inflammatory factors were measured using Enzyme-linked immunosorbent assay (ELISA), while pyroptosis-related proteins were detected through quantitative reverse transcription PCR (RT-qPCR) and western blot. Additionally, the levels of CD4+T and CD8+T cells were assessed using flow cytometry. An aged rats hip fracture model was established to further investigate the impact of dexmedetomidine on postoperative mobility, cognition function, pyroptosis and immune cells in rats. Results: Postoperative cognitive function in patients did not show significant alteration when compared with pre-operation levels (p > 0.05). There were notable reduction in the levels of interleukin-18 (IL-18), Caspase-3, Gasdermin-D (GSDMD) and NLR Family Pyrin Domain Containing 3 (NLRP3) (p < 0.001), accompanied by an increase in the proportion of CD4+T cells and an decrease in CD8+T cells after operation (p < 0.01). In aged rats, postoperative exploratory activities increased compared to their preoperative state. Compared with preoperative levels, the levels of interleukin-1β (IL-1β), IL-18, Caspase-3, GSDMD, and NLRP3 were significantly decreased (p < 0.001), the proportion of CD4+T cells was increased, and the proportion of CD8+T cells was decreased postoperatively (p < 0.01). Conclusions: Although there was no significant alteration in postoperative cognitive function in patients, dexmedetomidine may still play a role in mitigating POCD potentially due to its effects on reducing immune inflammation and pyroptosis markers. Further research is needed to fully understand the underlying mechanisms and its clinical implications.