Experimental study of inflammatory response and collagen morphometry with different types of meshes

Abstract

Purpose: To compare an inflammation score and collagen morphometry after incisional hernia repair with four different meshes at two time points. Methods: Four types of mesh were used to repair an abdominal wall incisional defect in Wistar rats: high-density polypropylene (HW/PP); low-density polypropylene (LW/PP); polypropylene mesh encapsulated with polydioxanone coated with oxidized cellulose (PP/CE); and expanded polytetrafluoroethylene (ePTFE). An inflammation score based on histological analysis and collagen morphometry was performed after 7 and 28 days after operation (POD). Results: Compared to LW/PP group at 7 POD, HW/PP group had lower (p = 0.014) and PP/CE group had higher inflammation scores (p = 0.001). At 28 POD, higher scores were seen in all the other groups compared to the LW/PP group (HW/PP, p = 0.046; PP/CE, p < 0.001; ePTFE, p = 0.027). Comparing groups individually at 7 and 28 PODs, all demonstrated lower inflammation score values at 28 POD (HW/PP, p < 0.001; LW/PP, p < 0.001; PP/CE, p = 0.002; ePTFE, p = 0.001). At 7 POD, higher amounts of collagen were detected in ePTFE compared to HW/PP (p < 0.001) and LW/PP (p = 0.004) and in PPCE group compared to HW/PP (p = 0.022). At 28 POD, no statistically significant difference was found. Comparing groups individually at 7 and 28 PODs, HW/PP and LW/PP showed larger amounts of collagen at the 28th POD, without any statistically significant differences for the PP/CE and ePTFE groups. Conclusions: Inflammation scores decreased in all groups at 28 POD. Collagen deposition was higher for non-composite meshes at 28 POD.