Pioglitazone Reduces Peritoneal Fibrosis via Inhibition of TGF-β, MMP-2, and MMP-9 in a Model of Encapsulating Peritoneal Sclerosis

Figures & data

Figure 1. Parietal peritoneum—H&E: (A) control, (B) Pio (no difference of pathological features was observed between the control and pioglitazone groups), (C) chlorhexidine gluconate (CG), and (D) CG + Pio [treatment group (CG + Pio) showed significant reduction in parietal peritoneal inflammation and submesothelial thickness].

Figure 2. Parietal peritoneum—Von Gieson (selected): (A) control, (B) Pio (no fibrosis was obsereved in the control and pioglitazone groups), and (C) chlorhexidine gluconate (CG), (D) CG + Pio [treatment group (CG + Pio) showed significant reduction in parietal peritoneal fibrosis and submesothelial thickness].

Table 1. Pathological results of the parietal peritoneum.

Groups	Fibrosis (%)	Parietal peritoneal thickness (μm)	Inflammation (score)	Vascularization (score)
I. Control	0.84 ± 0.54	7.01 ± 3.89	0	0
II. Pio	0.77 ± 0.15	12.3 ± 37	0	0
III. CG	10.76 ± 8.95,^**,^***	156.85 ± 29.13,^**,^***	1.5 ± 0.53,^**,^***	0.5 ± 0.92
IV. CG + Pio	4.77 ± 0.91,^**,^****	56.00 ± 35.33,^**,^****	0.62 ± 0.51,^**,^****	0.00 ± 0.00

Notes: Results are given as mean ± SD. CG, chlorhexidine gluconate.

*p < 0.05 versus control, ^**p < 0.05 versus Pio, ^***p < 0.05 versus CG+Pio, and ^****p < 0.05 versus CG.

Table 2. Pathological results of the visceral peritoneum.

Groups	Fibrosis (%)	Visceral peritoneal thickness (μm)	Inflammation (score)	Vascularization (score)
I. Control	0.29 ± 0.18	8.13 ± 5.05	0	0
II. Pio	0.24 ± 0.05	27.13 ± 9.41	0	0
III. CG	10.11 ± 4.43,^**,^***	182.1 ± 54.83,^**,^***	1.87 ± 0.35,^**,^***	0.37 ± 0.74
IV. CG + Pio	0.77 ± 0.28,^**,^****	50.62 ± 19.97,^**,^****	0.00 ± 0.00	0.00 ± 0.00

Notes: Results are given as mean ± SD. CG, chlorhexidine gluconate.

*p < 0.05 versus control, ^**p < 0.05 versus Pio, ^***p < 0.05 versus CG + Pio, and ^****p < 0.05 versus CG.

Figure 3. Zymography results.

Table 3. Gelatin zymography results.

Groups	MMP-2	Pro-MMP-2
I. Control	7.79 ± 1.48	149.37 ± 28.33
II. Pio	3.95 ± 1.53	78.47 ± 19.27 ,^**
III. CG	92.43 ± 58.63,^***	199.60 ± 37.02,^***,^****
IV. CG + Pio	51.79 ± 52.24,^***	103.31 ± 41.44,^**

Notes: Results are given as mean ± SD. CG, chlorhexidine gluconate; MMP, matrix metalloproteinase.

*p < 0.05 versus control, ^**p < 0.05 versus CG, ^***p < 0.05 versus Pio, and ^****p < 0.05 versus CG + Pio.

Table 4. Pro-MMP-2, MMP-2, pro-MMP-9, MMP-9 (Activity Assay), TIMP-1, and TIMP-2 (ELISA).

	Pro-MMP-2	ActiveMMP-2	Pro-MMP-9	Active MMP-9
	(pg/mg protein)	(pg/mg protein)	(pg/mg protein)	(pg/mg protein)
I. Control	55.75 ± 17.10	124.94 ± 13.91	1.91 ± 2.64	422.12 ± 51.53	259.07 ± 139.36,^**	13.35 ± 4.89
II. Pio	38.13 ± 32.02	159.92 ± 60.76	4.96 ± 14.05	439.48 ± 91.87	174.23 ± 42.98,^**	12.41 ± 9.11
III. CG	82.88 ± 32.02^**,^***,^****	114.88 ± 15.06	11.55 ± 13.87^**,^***,^****	431.78 ± 35.18	2576.69 ± 331.62^**,^***,^****	15.21 ± 6.14
IV. CG + Pio	49.25 ± 38.47	126.78 ± 9.32	1.23 ± 2.30	404.87 ± 58.81	1879.57 ± 497.48,^***,^****,	10.68 ± 2.49

Notes: The results are given as mean ± SD. MMP, matrix metalloproteinase; TIMP, tissue inhibitor of metalloproteinases; CG, chlorhexidine gluconate.

*p < 0.05 versus CG, ^**p < 0.05 versus CG + Pio, ^***p < 0.05 versus control, and ^****p < 0.05 versus Pio.

Table 5. TGF-β activity.

Groups	TGF-β (pg/mg protein)
I. Control	48.23 ± 22.93,^**
II. Pio	46.61 ± 25.97,^**
III. CG	154.2 ± 31.71^**,^***,^****
IV. CG + Pio	95.57 ± 36.30^**,^***,^****

Notes: The results are given as mean ± SD. TGF-β, transforming growth factor-beta; CG, chlorhexidine gluconate.

*p < 0.05 versus CG, ^**p < 0.05 versus CG + Pio, ^***p < 0.05 versus control, and ^****p < 0.05 versus Pio.