Objective

2

To investigate the mechanism of Yucan Granules on relieving renal fibrosis （RIF） in diabetic kidney disease （DKD） in db/db mice.

Methods

2

Six weeks old male C57BL/BKS-DB wild-type （db/m） mice （

n

=6） and C57BL/BKS-DB （db/db） mice （

n

=30） were used as experimental subjects. The db/m mice were set as the normal group， and the db/db mice were randomly divided into a model group， a positive control （losartan potassium） group （8.6 mg/kg）， and Yucan Granules low （1.3 g/kg）， medium （2.6 g/kg）， and high （5.2 g/kg） dose groups， with 6 mice in each group. The mice in each group were given the corresponding interventions by gavage every day for 10 consecutive weeks. After the intervention， serum and kidney tissues were collected to detect biochemical indicators of mice. Hematoxylin-eosin （HE）， Masson and Periodic Acid-Schiff （PAS） stainings were used to observe the pathological damage of renal tissue. Enzyme-linked immunosorbent assay （ELISA） was used to detect the levels of superoxide dismutase （SOD）， glutathione peroxidase （GSH-Px） and malondialdehyde （MDA） in renal tissue of each group. Cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dutP Nick end labeling （TUNEL） immunofluorescence staining. Immunohistochemistry was employed to detect B-cell lymphoma-2 （Bcl-2）， Bcl-2-associated X protein （Bax）， and caspase-3. Type I collagen （Col-1） and transforming growth factor-β1 （TGF-β1） in kidney were detected by Western blot.

Results

2

①Compared with the normal group， the levels of fasting blood glucose （FBG）， serum creatinine（SCr）， blood urea nitrogen （BUN）， urinary microalbumin （mALB） and urinary albumin/creatinine （UACR） in the model group were significantly increased （

P

<

0.01，

P

<

0.001）； Compared with the model group， the levels of FBG， SCr， BUN， mALB and UACR in each dose group of Yucan Granules were decreased to varying degrees （

P

<

0.05，

P

<

0.01，

P

<

0.001）. ②In the normal group， the glomeruli of mice were intact， with clear and distinct boundaries， and there was less deposition of blue collagen fibers； In the model group， significant morphological changes occurred in the kidneys of mice， including inte

rstitial inflammatory cell infiltration， mesangial matrix hyperplasia， glomerular hypertrophy， a large amount of blue collagen fiber deposition， homogeneous thickening of the basement membrane， and expansion of the mesangial matrix， invading the capillary lumen. The positive area of collagen fibers in each dose group of Yucan Granules was lower than that in the model group （

P

<

0.01）. ③Compared with the normal group， the expressions of Col-1 and TGF-β1 in the model group were increased （

P

<

0.01）， and the expressions of Col-1 and TGF-β1 in each treatment group were lower than those in the model group， while the expressions of Col-1 in the medium and high dose groups of Yucan Granules were different from those in the model group （

P

<

0.01）； The expression of TGF-β1 in the high-dose group of Yucan Granules was different from that in the model group （

P

<

0.05）. Compared with the normal group， the levels of SOD and GSH-Px in the kidney tissues of the model group were decreased （

P

<

0.01，

P

<

0.001）； After the intervention of Yucan Granules， the levels of SOD and GSH-Px in the kidney tissues of each group were increased （

P

<

0.05，

P

<

0.01，

P

<

0.001）. The level of MDA in the kidney tissues of the model group was higher than that in the normal group （

P

<

0.01）； After the intervention of Yucan Granules， the level of MDA in the kidneys of mice was decreased （

P

<

0.01，

P

<

0.001）. ④Compared with the normal group， the number of TUNEL-stained positive cells （apoptotic cells） in the model group was significantly increased （

P

<

0.01）； Compared with the model group， the number of TUNEL-stained positive cells in each dose group of Yucan Granules was decreased （

P

<

0.05，

P

<

0.01）. ⑤Compared with the normal group， the expression levels of Bax and caspase-3 in the

model group were elevated significantly （

P

<

0.01）， and decreased after the intervention of Yucan Granules at each dose （

P

<

0.01）. Compared with the normal group， the expression level of Bcl-2 in the model group was decreased （

P

<

0.01）， and increased after the intervention of Yucan Granules at each dose （

P

<

0.01）.

Conclusions

2

Yucan Granules can reduce FBG， improve renal function， reduce proteinuria and improve antioxidant capacity in db/db mice. Its mechanism may be related to inhibiting renal cell apoptosis.