Page 216 - Prevention and Treatment of Incisional Hernia- New Techniques and Materials

Chapter 10
Tissue reaction
For each group, ve meshes with the adjacent abdominal wall were xed in 4 % neutral bu ered formalin. After routine tissue processing, sections were cut and stained with hematoxylin and eosin (H&E) or picrosirius red.
H&E staining
Para n sections were dewaxed and stained with hematoxylin (Sigma-Aldrich, Seelze, Germany). After washing in tap water and demiwater, the sections were stained with eosin (Sigma-Aldrich). Subsequently, the sections were dehydrated in alcohol and xylene and mounted with Entallan (Merck, Darmstadt, Germany). Slides were analyzed with a light microscope (Olympus, Tokyo, Japan).
Picrosirius red staining
Para n sections were dewaxed, rehydrated, and stained with 0.1 % Sirius Red F3BA (Direct Red 80; Fluka Chemie, Zwijndrecht, The Netherlands) in a saturated picric acid solution for 1 h. Brief washing in 0.1 % acetic acid was followed by rapid dehydration in 100 % alcohol.
After a xylene bath, the slides were mounted with Entellan (Merck). Subsequently they were analyzed using a polarized light microscope (Olympus) with polarization lters whereby the collagen bers show birefringence. This technique allows the orientation of the collagen bers to be visualized, indicating the amount of collagen new formation(23).
In the H&E-stained samples, the degree of in ammation was scored using the following grading scale: grade 1 (mild in ammatory reaction with a few giant cells, occasional lymphocytes, and plasma cells), grade 2 (moderate reaction with giant cells and increased numbers of admixed lymphocytes, plasma cells, eosinophils, and neutrophils), and grade 3 (severe in ammatory reaction with micro abscesses).
Statistical analysis
Because the data were not normally distributed, adhesion formation, incorporation, shrinkage, and tenacity were compared using nonparametric tests (Kruskal-Wallis, Mann–Whitney). Therefore, all results were presented using the median and the interquartile range (IQR). After the amount of adhesion formation and the percentage of incorporated mesh edge had been assessed, these parameters were used to determine the Spearman’s rank correlation
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