Objective To observe the effect of electroacupuncture(EA)on renal function and autophagy-related protein expression in diabetic nephropathy(DN) rats

so as to explore its mechanisms underlying improvement of DN. Methods Male Wistar rats were randomly divided into normal control

DN model and EA groups(n=8 rats in each group). The DN model was established by high-fat diet(for 4 weeks) + streptozotocin(STZ

35 mg/kg

i.p.). EA(2 Hz/15 Hz

1 mA) was applied to bilateral “Shenshu”(BL23)and “Zusanli”(ST36)for 20 min

5 times a week for 6 consecutive weeks. The urine volume in 24 h(24 h-UV) was recorded

the levels of urine protein in 24 h(24 h-UP)

blood urea nitrogen(BUN) and serum creatinine(Scr) were detected by using an automatic biochemical analyzer

and the fasting blood glucose(FBG) was detected using rapid blood glucose paper test. The histopathological changes of glomerulus of the left kidney were observed after periodic acid-Schiff stain(PAS) and the ultra-microstructural changes

the numbers of autophagosomes and autophagic vacuoles of the right kidney were observed by transmission electronic microscope(TEM). The expression and localization of podocyte marker protein Nephrin was detected by using immunofluorescence assay

and the expression levels of autophagy-related proteins microtubule associated protein 1(LC3)

Beclin-1

p62 and Nephrin in the kidney tissue measured by Western blot. Results Before treatment

compared with the normal control group

the levels of 24 h-UV

24 h-UP and FBG were significantly increased(P<0.01) in the model and EA groups. After treatment

compared with the normal group

the levels of 24 h-UV

24 h-UP

FBG

BUN

Scr and p62 protein expression were signi-ficantly increased(P<0.01)

and the expression levels of LC3Ⅱ

Beclin-1 and Nephrin proteins and ratio of LC3Ⅱ/Ⅰ were significantly decreased(P<0.01) in the model group. Compared with the model group

the levels of 24 h-UV

24 h-UP

FBG

BUN and p62 were apparently decreased(P<0.01

P<0.05)

while the expression levels of LC3Ⅱ

Beclin-1 and Nephrin proteins and ratio of LC3Ⅱ/Ⅰ were obviously up-regulated(P<0.01

P<0.05) in the EA group. No significant changes were found in the level of Scr after EA(P>0.05) and in the expression levels of LC3 Ⅰ after modeling and EA(P>0.05). Outcomes of PAS showed blurred structure of the glomerulus with obvious proliferation of glomerular mesangial cells

increase of cell matrix

and thickening of basement membrane of the glomerulus and renal tubule

atrophy of epithelia cells of renal tubules and infiltration of inflammatory cells in the renal interstitum; and TEM revealed fusion and exfoliation of some foot processes

bareness or thickening of some basement membrane

and reduction of number of autophagosomes or autophagobubbles in podocytes in the model group

which was relatively milder in the EA group. Conclusion EA can effectively alleviate kidney damage in DN rats

which may be related to its function in facilitating autophagy in the kidney.