Objective To explore the protective effect and molecular mechanism of electroacupuncture(EA) preconditioning on renal injury in type 2 diabetic rats. Methods Fifty male Wistar rats were randomly divided into control

model

EA

EA+inhibitor

and inhibitor groups

with 10 rats in each group. Diabetes model was established by high fat and high glucose diet and intraperitoneal injection of streptozotocin(40 mg/kg). EA(2 Hz

1 mA) preconditioning was applied to “Guanyuan”(CV4)

“Zhongwan”(CV12)

bilateral “Zusanli”(ST36) and “Fenglong”(ST40) for 15 min

once every other day for 8 weeks. Rats of the inhibitor and EA+inhibitor groups were given intraperitoneal injection of 3-TYP(50 mg/kg) once every other day for a total of 3 times. The body weight

kidney mass

and renal index were recorded. The contents of urine microalbumin(ALB)

24 h urine 8-hydroxydeoxyguanosine(8-OHdG) and activities of reactive oxygen species(ROS)

superoxide dismutase(SOD)

catalase(CAT)

glutathione glycine peroxidase(GSH-Px) in kidney were detected by ELISA. The activities of mitochondrial respiratory chain enzyme complex(RCCⅠ—RCCⅣ) in kidney were detected using spectrophotometric method. HE staining

Masson staining and transmission electron microscopy were used to observe the changes of renal structure. The protein and mRNA expressions of silent information regulator 3(Sirt3)

manganese superoxide dismutase(MnSOD) in kidney were detected by Western blot and quantitative real-time PCR

respectively. Results After modeling and compared with the control group

the contents of ALB

the renal index

activity of ROS and content of 8-OHdG

and the renal collagen volume fraction(CVF) were increased(P<0.01)

while the activities of SOD

CAT and GSH-Px

RCCⅠ—RCCⅣ

and the mRNA and protein expressions of Sirt3 and MnSOD were decreased(P<0.01). After the treatment and compared with the model group

the contents of ALB

the renal index

ROS

8-OHdG

and the CVF were decreased in the EA group(P<0.01

P<0.05)

while the activities of SOD

CAT

GSH-Px

RCCⅠ—RCCⅣ

and Sirt3 and MnSOD expression levels were increased(P<0.01

P<0.05);the RCCⅡ activity and the expression level of MnSOD mRNA were increased(P<0.05) in the EA+inhibitor group; the ALB and 8-OHdG contents and the CVF in the inhibitor group were increased(P<0.05)

while the activity of SOD

and Sirt3 and MnSOD expression levels were decreased(P<0.05). In comparison with the EA group

the contents of ALB

the renal index

activities of ROS and 8-OHdG contents

and the CVF were increased(P<0.05

P<0.01)

activities of SOD

CAT and GSH-Px and RCCⅠ and RCCⅡ

and the mRNA and protein expressions of Sirt3 and MnSOD were decreased(P<0.05

P<0.01) in both EA+inhibitor group and inhibitor group

whereas the activities of RCCⅢ and RCCⅣ were decreased in the inhibitor group(P<0.05). The therapeutic effect of inhibitor was notably inferior to that of EA+inhibitor in decreasing ALB and 8-OHdG contents

and CVF(P<0.01)

and in up-regulating SOD and RCCⅡ activities

Sirt3 and MnSOD expression levels(P<0.01

P<0.05). Conclusion EA preconditioning can increase the expressions of renal Sirt3 and MnSOD in type 2 diabetic rats

thereby reducing the oxidative stress response and protecting the kidneys.