Expression of heat shock protein 70 mRNA in polymorphonuclear cells responding to surgical stress

Purpose. This study was performed to investigate the expression of heat shock protein (HSP) 70 mRNA in polymorphonuclear neustrophils (PMN) as a possible new biomarker for surgical stress. Methods. The HSP70 mRNA in PMN of 10 patients who underwent lobectomy was evaluated by Northern blot analysis. Their leukocyte counts, including white blood cells (WBC) and PMN, plasma cortisol levels, and plasma interleukin-6 (IL-6) levels, were obtained by cell counting, radioimmunoassay, and enzyme-linked immunosorbent assay, respectively. Results. The level of HSP70 mRNA in PMN slightly increased at the end of surgery and showed a significant increase 6 h after surgery. It promptly decreased at 24 h postoperatively and returned to the basal preanesthetic level 48 h after surgery. On the other hand, WBC/PMN counts, plasma cortisol, and IL-6 significantly increased at the end of surgery. WBC/PMN counts remained at increased levels until 48 h postoperatively. Cortisol peaked at 6 h postoperatively and gradually decreased. IL-6 reached a maximum at 1 h postoperatively, then tapered down to its basal level at 48 h postoperatively. Conclusion. Expression of HSP70 mRNA in PMN that is induced after thoracic surgery appears to be a promising candidate as a marker for evaluating surgical stress. Received for publication on August 31, 1998; accepted on March 10, 1999