Th2-biased GATA-3 transgenic mice developed severe experimental peritoneal fibrosis compared with Th1-biased T-bet and Th17-biased RORγt transgenic mice

Abstract

Encapsulating peritoneal sclerosis is one of the most serious complications of long-term peritoneal dialysis. The pathogenesis of encapsulating peritoneal sclerosis has not been elucidated, but several putative factors necessary for the development of peritoneum fibrosis (PF) have been reported. However, the roles of T helper (Th) cells in the progression of PF are unknown. The purpose of this study was to clarify the roles of Th1, Th2, and Th17 cells in the progression of PF. T-bet, GATA-3, and RORγt are Th1, Th2, and Th17 lineage commitment transcription factors, respectively. We previously generated Th1-biased (T-bet transgenic (Tg)) mice, Th2-biased (GATA-3 Tg) mice, and Th17-biased (RORγt Tg) mice. In this study, Th1, Th2, Th17-biased, and wild-type mice were administered chlorhexidine gluconate (CG) intraperitoneally and analyzed on day 21. CG-injected GATA-3 Tg mice showed a distended intestinal tract and developed marked thickening of the submesothelial space compared with the other groups. CG-injected GATA-3 Tg mice also showed significant expression of α-SMA positive cells, macrophages, and collagen III in the submesothelium. In contrast, CG-injected T-bet Tg mice only developed mild peritoneal fibrosis. Cytokines analysis in peritoneal fluid showed that IFN-γ was significantly increased in CG-injected T-bet Tg mice and that IL-13 was significantly increased in CG-injected GATA-3 Tg mice. Moreover, intraperitoneal administration of IFN-γ improved PF in GC-injected wild-type mice. Our results suggest that Th2 cells may play roles in the development of experimental PF and that Th1 cells may alleviate the severity of experimental PF.

Fig. 1.

Body weight changes of control mice and chlorhexidine gluconate (CG)-injected mice. The ratios of body weight change between the weights on day 21 and before treatments are shown. W, wild-type mice; T, T-bet transgenic (Tg) mice; G, GATA-3 Tg mice; R, RORγt Tg mice. Data represent means ± SEM. *P<0.01, CG-injected GATA-3 Tg mice vs. control GATA-3 Tg mice, CG-injected wild-type mice, and T-bet Tg and RORγt Tg mice.

Fig. 2.

Macroscopic findings of the peritoneum of CG-injected mice. CG-injected mice were sacrificed on day 21 and observed macroscopically. Representative mice are shown. CG-injected GATA-3 Tg mice developed severe distended intestinal tract and surface bleeding. The gastrointestinal loop in the CG-injected GATA-3 Tg mouse shows adhesion and bleeding.

Fig. 3.

Representative light microscopic features of peritoneal tissue on days 21 in control mice (A) and CG-injected wild-type (W), T-bet Tg (T), GATA-3 Tg (G), and RORγt Tg (R) mice (B) (Masson-trichrome stain, original magnification ×100, scale bar 100 µm). Bars indicate thickness of the submesothelium. (C) Bar graph showing the thickness of the submesothelial zone. Data represent means ± SEM. *P<0.01 vs. CG-injected T-bet Tg and RORγt Tg mice; **P<0.05 vs. CG-injected wild-type mice; ***P<0.05 vs. CG-injected T-bet Tg mice.

Fig. 4.

Immunohistochemistry of α-SMA expression (arrowheads) (A), collagen III expression (B), and F4/80-positive cells (arrowheads) (C) in peritoneal tissue on days 21 in CG-injected wild-type (W), T-bet Tg (T), GATA-3 Tg (G), and RORγt Tg (R) mice (original magnification ×200 (A and C), ×100 (B); scale bar 100 µm).

Fig. 5.

Expression of cytokines, IFN-γ (A) and IL-13 (B), in peritoneal fluid of control and CG-injected mice. W, wild-type mice; T, T-bet Tg mice; G, GATA-3 Tg mice; R, RORγt Tg mice. Data represent means ± SEM. *P<0.01 vs. CG-injected wild-type mice, GATA-3 Tg mice, and RORγt Tg mice; **P<0.05 vs. CG-injected T-bet Tg mice and RORγt Tg mice; ***P<0.01 vs. CG-injected T-bet Tg mice and RORγt Tg mice; P<0.05 vs. CG-injected wild-type mice; n=5 in each group.

Fig. 6.

Intraperitoneal administration of IFN-γ in CG-injected wild-type mice. Representative light microscopic features of peritoneal tissue on days 21 in saline-injected, CG with saline-injected, and CG with IFN-γ-injected wild-type mice (A) (Masson-trichrome stain, original magnification ×100, scale bar 100 µm). Bars indicate thickness of the submesothelium. (B) Bar graph showing the thickness of the submesothelial zone. Data represent means ± SEM. *P<0.01 vs. saline-injected and CG with IFN-γ injected wilt-type mice; **P<0.01 vs. saline-injected wild-type mice.