摘要
Object. Paraspinal muscle injury is a common but neglected complication of posterior spinal surgery. Evidence suggests that surgical retraction places mechanical and oxidative stress on the paraspinal muscles and that inflammation is a major postoperative pathological finding in the muscles. The roles of cyclooxygenase (COX)—2 and nuclear factor (NF)—κB in the inflammatory processes after retraction remains to be clarified.Methods. In the control group, paraspinal muscles were dissected from the spine via a posterior incision and then laterally retracted. Paraspinal muscle specimens were harvested before as well as at designated time points during and after persistent retraction. The time course of NF-κB activation was determined by gel shift assay. Expression of COX-2 was examined using Western blot analysis and immunohistochemistry. The severity of inflammation was evaluated based on histopathology and myeloperoxidase (MPO) activity. The NF-κB activation was inhibited by the administration of pyrrolidine dithiolcarbamate (PDTC) in the PDTC-treated group. Retraction induced early activation of NF-κB in paraspinal muscle cells. The expression of COX-2 could not be detected until 1 day postoperativley, reaching a peak at 3 days. The time course of COX-2 expression correlated with that of inflammatory responses and MPO activity. Pretreatment with PDTC inhibited intraoperative NF-κB activation and greatly downregulated postoperative COX-2 expression and inflammation in the muscles. Postinflammation fibrosis was also abolished by PDTC administration.Conclusions. Both NF-κB-regulated COX-2 expression and inflammation play an important role in the pathogenesis of surgery-associated paraspinal muscle injury. The therapeutic strategy of NF-κB inhibition may be applicable to the prevention of such injury.