Benzodiazepines inhibit the rate of neutrophil apoptosis

Background. Benzodiazepines, which are commonly administered perioperatively, can depress immune function. Neutrophil apoptosis plays a central role in the regulation of inflammation. This is particularly important during and after surgery. Aim. To examine the effects of benzodiazepines (midazolam and diazepam) on neutrophil apoptosis. Methods. Venous blood samples were withdrawn from patients scheduled to undergo elective surgery, (a) immediately prior to, and 10 minutes after administration of midazolam 0.2mg/kg intravenously (n=11) and (b) immediately prior to, and 60 minutes after administration of diazepam 10mg po (n=10). Neutrophil apoptosis was measured by Annexin V-FITC after 1 and 12 hours in culture. Results. The percentage of apoptotic cells was significantly less after midazolam at 12% (11.9) hours in culture compared to pre-midazolam 29.7% (13.3) (p<0.05). After diazepam, the rates of neutrophil apoptosis were also significantly less after 12 hours in culture (p<0.05). Conclusion. Administration of benzodiazepines in clinically relevant doses inhibits neutrophil apoptosis. In the perioperative period, this may influence the inflammatory response to surgery.