Objective

2

The effect of modified Shengjiangsan on immunoglobulin A （IgA） nephropathy was observed. The microRNA-148b （miRNA-148b）， interleukin 6 （IL-6）， core 1 beta 1，3-galactosyltransferase （C1GALT1）， molecular chaperone Cosmc （core1

β

3-Gal-T-specific molecular chaperone C1GALT1C1）， and galactose-deficient IgA1 （Gd-IGA1） in serum and kidney tissues of IgA nephropathy rats were detected to explore the underlying mechanism. The result is expected to lay a scientific basis for clinical application of modified Shengjiangsan in the treatment of IgA nephropathy.

Method

2

A total of 42 SPF male SD rats were randomized into the normal group （8rats） and modeling group （34 rats） with the random number table method. After one week of adaptive feeding， rats for modeling were given bovine serum albumin （BSA， gavage）， lipopolysaccharide （LPS， injection into tail vein）， carbon tetrachloride （CCl

4

， subcutaneous injection）， and castor oil to induce IgA nephropathy. After modeling， two rats were randomly selected to test the modeling outcome. Then the model rats were classified into the model group， low-dose Chinese medicine group （modified Shengjiangsan，6.27 g·kg

-1

）， high-dose Chinese medicine group （modified Shengjiangsan，12.54 g·kg

-1

）， and benazepril group （10 mg·kg

-1

） with the random number table method， 8 in each group. The administration （gavage， once a day） lasted 4 weeks. The 24-h urinary total protein （24 h-UTP） was detected at the end of the 1

st

， 9

th

， and 13

th

week of the experiment. At the 14th week， after anesthesia， femoral artery blood was collected and centrifugated. The supernatant was collected to detect albumin （ALB）， aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， serum creatinine （SCr）， and blood urea nitrogen （BUN）. The expression levels of IL-6 and Gd-IGA1 were determined by enzyme-linked immunosorbent assay （ELISA）. Based on hematoxylin-eosin （HE）/Masson/periodic Schiff-methenamine silver （PASM） staining， the pathological changes of renal tissues were observed. Ultrastructural changes of glomeruli were observed by transmission electron microscopy. The expression of miRNA-148b， IL-6， C1GALT1， and C1GALT1C1 was detected by immunohistochemistry. The mesangial area of the glomeruli was observed by immunofluorescence. Real-time polymerase chain reaction （Real-time PCR） was employed to determine the mRNA levels of mirNA-148b， IL-6， C1GALT1， and C1GALT1C1， and Western blot was used to detect the protein levels of IL-6， C1GALT1， and C1GALT1C1.

Result

2

Compared with normal group， the model group showed increase in the content of 24 h-UTP， SCr， ALT， IL-6， and GD-IGA1 （

P

<

0.05）， decrease in ALB content （

P

<

0.05）. Moreover， rats in the model group demonstrated hyperplasia of glomerular mesangial cells， thickening of mesangial area， podocyte foot process effacement， and a large number of granular IgA immune complex in the mesangial area. In addition， the model group showed increase in the expression of IL-6 in mesangial area and podocytes， decrease in the expression of C1GALT1 and C1GALT1C1 in mesangial area and podocytes， enhanced expression of IL-6 mRNA and miRNA-148b （

P

<

0.01）， weakened expression of C1GALT1 mRNA and C1GALT1C1 mRNA （

P

<

0.01）， rise of IL-6 protein expression （

P

<

0.01）， and reduction in the protein expression of C1GALT1 and C1GALT1C1 （

P

<

0.01）. Compared with the model group， modified Shengjiangsan decreased the content of 24 h-UTP， SCr， ALT， IL-6， and Gd-IGA1 （

P

<

0.05） and increased the content of ALB （

P

<

0.05，

P

<

0.01）. Moreover， with the treatment of this Chinese medicine， the pathological damage was significantly alleviated and the deposition of IgA immune complex in basement membrane was reduced. The expression of IL-6 in the mesangial area and podocytes of rats was decreased， and the expression of C1GALT1 and C1GALT1C1 in the mesangial area and podocytes of rats was increased. Moreover， the expression of IL-6 mRNA and miRNA-148b was decreased （

P

<

0.01）， and the expression of C1GALT1 mRNA and C1GALT1C1 mRNA was increased （

P

<

0.01）. The protein expression of IL-6 was decreased （

P

<

0.05，

P

<

0.01）， and the protein expression of C1GALT1 and C1GALT1C1 was enhanced （

P

<

0.05，

P

<

0.01）. The Chinese medicine group showed obvious dose-effect trend.

Conclusion

2

Modified Shengjiangsan may reduce the expression of miRNA-148b and IL-6 in serum and kidney tissue of IgA nephropathy rats， restore the expression of C1GALT1 and C1GALT1C1， and decrease the generation of Gd-IGA1， so as to reduce renal pathological damage and proteinuria， protect the kidney protection， and finally delay the disease progression. Moreover， the effect is enhanced with the rise of dose.