Losartan Alleviates Renal Fibrosis by Down-Regulating HIF-1α and Up-Regulating MMP-9/TIMP-1 in Rats with 5/6 Nephrectomy

Figures & data

Figure 1. Differences of urine protein and NAG enzyme between different groups.

Note: Compared with sham group, 24-h urinary protein and urinary NAG levels in model group were significantly increased (p < 0.05), but losartan reduced urine protein and NAG levels (p < 0.05).

Table 1. Cys-C (mg/L) levels in different groups .

Group	4 weeks	8 weeks	12 weeks
Sham	0.56 ± 0.04	0.54 ± 0.04	0.83 ± 0.01
Model	0.74 ± 0.01^a	0.77 ± 0.04^a	0.97 ± 0.02^a
Losartan	0.64 ± 0.02^a,^b	0.65 ± 0.03^a,^b	0.91 ± 0.01^a,^b

Notes: ^ap < 0.05 versus sham group.

^bp < 0.05 versus model group.

Table 2. BUN and Scr levels in different groups .

	BUN (mmol/L)			Scr (μmol/L)
Group	4 weeks	8 weeks	12 weeks	4 weeks	8 weeks	12 weeks
Sham	5.53 ± 0.51	6.58 ± 0.48	5.36 ± 0.49	17.87 ± 2.23	18.00 ± 2.39	17.62 ± 1.92
Model	16.99 ± 5.49^a	15.52 ± 3.30^a	18.74 ± 3.87^a	60.00 ± 7.66^a	65.00 ± 23.29^a	66.42 ± 17.21^a
Losartan	13.58 ± 2.16^a	15.45 ± 1.29^a	17.04 ± 1.84^a	47.85 ± 5.69^a,^b	50.71 ± 8.32^a,^b	51.28 ± 8.46^a,^b

Notes: ^ap < 0.05 versus sham group.

^bp < 0.05 versus model group.

Figure 2. Histopathological changes in rat renal tissue samples at 12th week (HE, Hematoxylin–eosin staining ×200; Masson, Masson staining ×200; EM, electron microscopy ×5000); (A) There was no significant histological abnormality in the sham group (HE); (B) glomerular sclerosis, renal tubular epithelial cell degeneration and necrosis, partial tubular atrophy, and some degree of interstitial fibrosis could be seen (HE); (C) in the losartan group, only local mild glomerular and tubular epithelial lesions were observed (HE); (D) there was no fibrosis of the interstitium in the sham group (Masson); (E) glomerular sclerosis with moderate fibrosis of the interstitium was seen in the model group (Masson); (F) a less severe renal fibrosis was observed in the losartan group (Masson); (G) the ultrastructure of intact glomerulus was seen in the sham group (EM); (H) an bending and thickening of the glomerular basement membrane, and podocytes swelling with fusion and flattening of part of the foot processes were found in the model group (EM); (I) less severe damages of the glomerular basement membrane and podocytes were observed in the losartan group (EM); (J) the normal tubule epithelial cells and basement membrane were seen in the control group (EM); (K) in the model group, tubular swelling and degeneration were found with significant interstitial fibroblast proliferation (EM); (L) a Less severe tubulointerstitial damage was observed in the losartan group (EM). Sham: sham-operation group, M: model group, L: losartan group.

Table 3. Comparison of pathological score of rat kidneys .

	Glomerulosclerosis			Tubulointerstitial damage
Group	4 weeks	8 weeks	12 weeks	4 weeks	8 weeks	12 weeks
Sham	0.02 ± 0.02	0.03 ± 0.02	0.03 ± 0.03	0.01 ± 0.02	0.03 ± 0.05	0.06 ± 0.08
Model	0.23 ± 0.06^a	0.56 ± 0.12^a	1.02 ± 0.10^a	0.45 ± 0.10^a	0.90 ± 0.14^a	1.30 ± 0.13^a
Losartan	0.12 ± 0.03^a,^b	0.33 ± 0.11^a,^b	0.56 ± 0.05^a,^b	0.28 ± 0.07^a,^b	0.46 ± 0.13^a,^b	0.71 ± 0.11^a,^b

Notes: ^ap < 0.05 versus sham group.

^bp < 0.05 versus model group.

Figure 3. The expressions of HIF-1α, TGF-β1, MMP-9, and TIMP-1 in rat renal tissues at 12th week (immunochemistry ×200). (1) In sham group, there was a very little expression of HIF-1α in the tubulointerstitial tissues, but abundant expression in tubular tissues in the model group. After losartan treatment, HIF-1α level in renal tissue was lower than in model group (p < 0.05). (2) A tracing tubulointerstitial expression of TGF-β1 was found in the sham group, whereas the expression in the model group increased significantly. Losartan treatment led to significantly decreasing TGF-β1 expression (p < 0.05). (3) Thimbleful glomerular expression of MMP-9 was detected in the sham group, while expression increased in the model group, and losartan treatment further increased significantly glomerular MMP-9 expression (p < 0.05). (4) A very small amount of renal expression of TIMP-1 was detected in the sham group, while expression increased in the model group, and losartan treatment decreased significantly renal TIMP-1 expression (p < 0.05). Sham: sham-operation group, M: model group, L:losartan group.

Table 4. Renal expression of HIF-1α, TGF-β1, MMP-9, and TIMP-1 in different groups .

Group	HIF-1α	TGF-β1	MMP-9	TIMP-1	MMP-9/TIMP-1
Sham	0.39 ± 0.14	0.32 ± 0.16	0.35 ± 0.17	0.38 ± 0.19	0.96 ± 0.35
Model	4.75 ± 0.65^a	6.22 ± 0.78^a	1.87 ± 0.41^a	6.39 ± 0.56^a	0.29 ± 0.06^a
Losartan	2.56 ± 0.419^a,^b	4.08 ± 0.49^a,^b	2.46 ± 0.32^a,^b	4.60 ± 0.54^a,^b	0.53 ± 0.09^a,^b

Notes: ^ap < 0.05 versus sham group.

^bp < 0.05 versus model group.

Figure 4. The difference of HIF-1α (A), TGF-β1 (B), MMP-9 (C), and TIMP-1 (D) protein expressions in rat renal tissues at 12 weeks between different groups. Sham: sham-operation group, M: model group, L: losartan group.

Notes: The expressions of HIF-1α, TGF-β1, MMP-9, and TIMP-1 in the model group were higher than those in the sham group (p < 0.05), losartan treatment induced a decrease in HIF-1α, TIMP-1, and TGF-β1 and an increase in MMP-9 (p < 0.05). #p < 0.05 versus sham-operation group, *p < 0.05 versus model group.