Figure 6: Immunohistological analysis of the degree of scaffold infiltration by CD163 (a), CD68 (b), and hPH-positive fibroblasts (d) after 9 and 30 days, as well as the CD163/CD68 ratio (c). At day 30 postimplantation, a decrease of infiltrating CD163-positive macrophages could be observed in all implants compared to untreated scaffolds. Furthermore, a decrease of infiltrating CD68+macrophages could be observed in the BP group, as well as after cross-linking with GP compared to untreated scaffolds at day 30. Untreated and cross-linked scaffolds, except the CDI and GA groups, showed a macrophage M2 phenotype switch at day 30 postimplantation, indicated by a positive CD163/CD68 ratio at day 30 compared to ratio at day 9. All data were represented as ratios of specific cells/total cells ± SEM. Five microscopic fields (magnification ×1000) of one slide per rat were analyzed ( 𝑛 = 3 per group and day). An average of 7 5 ± 2 . 1 5 total cells per microscopic field was counted to generate the ratio of cells/total cells. All implants were compared by means and confidence interval to the untreated implant. Differences were considered as significant if confidence intervals do not overlap or by 𝑃 < 0 . 0 5 , see red line. Untreated: untreated scaffold; BP: bovine pericardium (St. Jude, USA); GP: genipin; GA: glutaraldehyde; CDI: carbodiimide; hPH: hydroxyl-prolyl-hydroxylase. * 𝑃 < 0 . 0 5 , ** = 𝑃 < 0 . 0 1 versus untreated decellularized esophagus tissue.