Figure 5

Genetic deletion of connective tissue growth factor (CTGF) reduced lymphangiogenesis and vascular endothelial growth factor-C (VEGF-C) expression in a mouse peritoneal fibrosis model induced by chlorhexidine gluconate (CG). Peritoneal fibrosis was induced by intraperitoneal injection of CG in wild-type mice (Control) and CTGF knockout (CTGF^−/−) mice. PBS-treated mice were used for comparison. (a–c) Immunohistochemical analysis showed that the increased expression of lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) and VEGF-C in the CG model was significantly decreased in CTGF^−/− mice compared with control mice. We found no significant differences in LYVE-1 and VEGF-C expression between PBS-treated control peritoneum and PBS-treated CTGF^−/− peritoneum. The staining intensity for VEGF-C was scored as follows: 0, absent; 1, mild; 2, moderate; 3, extensive. Arrows indicate LYVE-1-positive lymphatic vessels. Insets show magnification of dotted-line boxed areas. Scale bars; 100 μm. (d,e) Quantitative polymerase chain reaction analysis showed that the increased expression of VEGF-C and VEGF receptor-3 (VEGFR-3) messenger RNA (mRNA) in the CG model was significantly decreased in CTGF^−/− mice compared with control mice. We found no significant differences in VEGF-C or VEGFR-3 mRNA expression between the PBS-treated control peritoneum and PBS-treated CTGF^−/− peritoneum. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an internal reference. Graphs show means ± SD (n = 4 for each group). n.s.; not significant.