L-arginine-induced chronic pancreatitis in mice: Evaluating effects of pirfenidone and simvastatin

Table 1 Animal grouping and dosing schedule

Animal group	Treatment
I: Normal control group (n = 8)	Normal saline
II: Model control group (n = 10)	L-arginine administered: i.p. 4.50 g/kg, 2 doses at 1-hour intervals for week 1; i.p. 4.60 g/kg, 2 doses at 1-hour intervals for week 2; and i.p. 4.75 g/kg, 2 doses at 1-hour intervals for weeks 3 and 4
III: Pirfenidone-treated group (n = 10)	L-arginine administered: i.p. 4.50 g/kg, 2 doses at 1-hour intervals for week 1; i.p. 4.60 g/kg, 2 doses at 1-hour intervals for week 2; and i.p. 4.75 g/kg, 2 doses at 1-hour intervals for weeks 3 and 4. Pirfenidone administered: p.o. 400mg/kg, from week 3
IV: Simvastatin-treated group (n = 10)	L-arginine administered: i.p. 4.50 g/kg, 2 doses at 1-hour intervals for week 1; i.p. 4.60 g/kg, 2 doses at 1-hour intervals for week 2; and i.p. 4.75 g/kg, 2 doses at 1-hour intervals for weeks 3 and 4. Simvastatin administered: p.o. 1 mg/kg, for weeks 3-7
V: Pirfenidone + simvastatin-treated group (n = 10)	L-arginine administered: i.p. 4.50 g/kg, 2 doses at 1-hour intervals for week 1; i.p. 4.60 g/kg, 2 doses at 1-hour intervals for week 2; and i.p. 4.75 g/kg, 2 doses at 1-hour intervals for weeks 3 and 4. Pirfenidone administered: p.o. 400 mg/kg, for weeks 3-7; Simvastatin administered; p.o. 1mg/kg, for weeks 3-7
Total animals	48

i.p.: Intraperitoneal; p.o.: Per oral.

Table 2 Scoring for histopathological changes

Histopathological changes	Scoring
	NC	MC	Pir	Sim	Pir + sim
Inflammatory cell infiltration	0	3	1	1	1
Congestion	0	3	1	2	1
Fatty replacement of exocrine pancreas	0	3	1	1	1
Areas of abnormal pancreatic tissue architecture from the total parenchyma1	01	31	21	11	11
Glandular atrophy	0	3	1	0	0
Fibrosis/collagen deposition in exocrine pancreas (Masson’s trichome stain)	0	3	1	1	0
Distortion/degeneration of exocrine pancreas	0	3	2	1	1

¹The following grading was applied: 0 (absent); 1 (minimal); 2 (moderate); 3 (severe); 0¹ (absent); 1¹ (rare); 2¹ (minimal < 10% area); 3¹ (moderate < 50% area); and 4¹ (major > 50% area).

NC: Normal control; MC: Model control: Pir: Pirfenidone; Sim: Simvastatin.

Table 3 Marker levels across all study groups at weeks 4 and 7, mean ± SD

Animal group	TNF-α in pg/mL		IL-10 in pg/mL		TGF-β1 in pg/mL		GPx-1 in IU/mL		LPO in mmol/mL
	Week 4	Week 7	Week 4	Week 7	Week 4	Week 7	Week 4	Week 7	Week 4	Week 7
Normal control	8.07 ± 0.36	8.07 ± 0.36	9.85 ± 0.30	9.85 ± 0.50	240.73 ± 14.86	240.73 ± 8.71	5.48 ± 0.92	5.48 ± 0.92	122.19 ± 5.88	122.19 ± 5.88
Model control	13.70 ± 0.07	24.30 ± 2.01	18.60 ± 3.25	19.60 ± 1.27	434.91 ± 53.19	550.52 ± 42.18	2.44 ± 0.42	1.92 ± 0.21	114.82 ± 3.91	192.85 ± 0.98
Pirfenidone	8.37 ± 0.74	14.60 ± 1.42	12.80 ± 0.09	17.00 ± 1.37	288.95 ± 18.90	241.34 ± 20.45	2.08 ± 0.09	5.04 ± 0.43	126.18 ± 6.83	142.14 ± 1.60
Simvastatin	6.25 ± 0.26	19.30 ± 0.29	9.61 ± 0.27	17.40 ± 0.29	405.43 ± 19.30	273.43 ± 8.72	2.65 ± 0.06	7.54 ± 0.53	105.69 ± 12.50	169.16 ± 25.30
Pir + sim	19.60 ± 3.30	11.10 ± 1.57	14.20 ± 0.28	11.70 ± 1.12	277.10 ± 21.02	236.13 ± 6.95	4.50 ± 0.24	5.47 ± 0.34	164.84 ± 7.78	111.87 ± 7.36

GPx-1: Glutathione peroxidase 1; IL-10: Interleukin-10; LPO: Lipid peroxidation; TGF-β1: Transforming growth factor-beta 1; TNF-α: Tumor necrosis factor-alpha.

Table 4 Area of fibrosis across all study groups at week 7

Area	Normal control	Model control	Pirfenidone + simvastatin	Simvastatin-treated	Pirfenidone-treated
Average	2.21%	18.88%	3.99%	8.66%	6.81%