Introduction: Inflammatory response and tumor growth are increased after laparotomy compared with laparoscopy in some animal models. In vitro, the proinflammatory cytokines interleukin (IL)-6 and IL- 1β up-regulate the expression of angiogenic factors such as vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2). The aim of this study was to investigate the influence of postoperative inflammatory response on angiogenesis and tumor growth. Methods: Solid tumor induction was achieved through injection of 5 x106 B51LiM cells into the cecal wall of Balb/c mice. The animals were randomized into two groups: open cecectomy (OC) and laparoscopic- assisted cecectomy (LC). Serum IL-6, IL-1β and VEGF levels were determined postoperatively. On postoperative day 12, the mice were sacrificed.Tumor load score and weight were calculated. Immunohistochemistry for CD31 and COX-2 was performed on samples of tumor recurrence. Results: Tumor load score and weight were significantly greater after laparotomy than after laparoscopy (p < 0.01). Serum IL-6 (OC: 4157 ± 1.297 pg/ml versus. LC: 2.514 ± 1.417 pg/ml) and VEGF levels (OC: 231 ± 125 pg/ml vs. LC: 45 ± 9 pg/ml) were significantly higher in the laparotomy group (p < 0.01). Microvessel density (mean ± SD) was 34.3 ± 11.5 in the OC group versus. 15.5 ± 12.5 in the LC group (p < 0.01). COX-2 expression was also significantly higher in the OC group. A positive correlation was found between postoperative serum levels of IL-6 and VEGF (rho = 0.67; p < 0.001). VEGF levels were also correlated with microvessel density and tumor weight (rho = 0.63, p < 0.001). Conclusions: Increased systemic levels of proinflammatory cytokines are associated with greater angiogenesis and tumor growth after laparotomy than after laparoscopy in mice.
- Colon cancer
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