Abstract: Objective To study the effect of parecoxib sodium on tumor microenvironment in patients undergoing laparoscopic radical resection of rectal cancer. Methods Sixty patients undergoing laparoscopic surgery for radical rectal cancer resection were randomized into test group and control group (n=30). The patients in test control group received intravenous injections of 40 mg parecoxib sodium at the time of anesthesia induction, immediately after and at 12 h after the surgery, and those in the control group were injected with an equal volume of physiological saline at the same time points. Plasma levels of IL-6, TNF-α, and CXCL8 of the patients were measured using ELISA, and expressions of CXCL8, CXCR1, and CXCR2 in the peripheral blood mononuclear cells (PBMCs) were detected with Western blotting. Postoperative VAS scores and gastrointestinal reactions and disease regression at 6 months after the operation were recorded. Results Compared with the control patients, the patients in the test group showed significantly reduced plasma levels of IL-6, TNF-α, and CXCL8 (P<0.05) and milder elevations of CXCL8, CXCR1, and CXCR2 proteins in PBMCs (P<0.05) with significantly lower VAS scores at 12 h and 24 h after the operation (P<0.05) and lower postoperative incidence of adverse gastrointestinal reactions (P<0.05). At 6 months after the operation, the number of patients with metastasis or tumor recurrence was significantly smaller in the test group than in the control group (P>0.05). Conclusion Parecoxib sodium can improve the inflammatory microenvironment to promote patient recovery after laparoscopic radical resection of rectal cancer possibly through a mechanism that down-regulates CXCL8-CXCR1/2 expressions in the PBMCs.

Key words: rectal cancer; parecoxib; peripheral blood mononuclear cells; inflammation; chemokines