ZALAN BENEDEK, ORSOLYA HANKO BAUER, SORIN SORLEA, MARIUS FLORIN COROS, TIBOR MEZEI, RARES GEORGESCU STUDY OF BIOINTEGRATION AND TISSUE REACTION OF POLYETHYLENE TEREPHTALATE 3D AND POLYPROPYLENE SURGICAL MESHES IN RAT MODEL The aim of this experimental study is to compare the biointegration and tissue response to different surgical mesh types, inserted in various layers of the abdominal wall of Wistar rats. After 30 days, the rats were sacrificed and the meshes were removed en bloc with the subcutaneous tissue, muscular layer and peritoneum. Tissue response (fibrosis, inflammation) was measured using quantitative and semi-quantitative morphometry. We observed that polyethylene terephthalate 3D mesh induces significantly more fibrosis compared to polypropylene mesh and the fibrosis is absent or minimal in case of the control group. Tissue reaction, including fibrosis, is reduced around the polypropylene mesh. We also observed that fibrosis is more intense towards aponeurosis and peritoneum. We can conclude that the 3D mesh shows better biointegration if it is used in proper circumstances. Itís well tolerated by the organism if sutured to the aponeurosis and preferable with monofilament stitches.