Objective: To observe the effect of electroacupuncture (EA) on blood pressure, renal fibrosis and expression of tissue inhibitors of metalloproteinase-1 (TIMP-1), plasminogen activator inhibitor 1 (PAI-1), and alpha smooth muscle actin (α-SMA) in spontaneous hypertension rats (SHR), so as to explore its mechanisms underlying improving hypertensive renal damage.
Methods: Forty male SHR (15 weeks in age) were randomly divided into 5 groups: model, medication (Losartan), Shenshu, Geshu, and Shenshu＋Geshu groups(n=8 rats in each group), and the same age-old male 8 Wistar-Kyoto (WKY) rats were used as the normal control group. Rats of the medication group were treated by gavage of Losartan potassium solution (3 mg/mL, 30 mg·kg-1·d-1, once a day for 12 weeks), and those of the 3 EA groups treated by EA stimulation of bilateral "Shenshu" (BL23), "Geshu"(BL17) or both BL23 and BL17 (2 Hz/100 Hz, 1 mA, 15 min each time, once every other day for 12 weeks). The systolic blood pressure of the tail artery was measured before, and 4, 8 and 12 weeks after the intervention. The expression of TIMP-1, PAI-1 and α-SMA proteins of the right kidney tissue was measured by immunohistochemistry. Histopathological changes of the right renal tissue were observed under light microscope after H.E. stain.
Results: The blood pressure was significantly higher in the mo-del group than those in the normal control group (P<0.01), and considerably decreased at the 4th , 8th, and 12th week of the interventions in the medication and 3 EA groups (P<0.01). The expression levels of renal TIMP-1, PAI-1 and α-SMA proteins were notably higher in the model group than those in the normal control group and considerably decreased at the 12th week of the interventions in the medication and 3 EA groups than in the model group (P<0.01). H.E. staining of the renal tissue showed disordered arrangement of the renal cells, congestion and dilation of capillaries with thickened vascular wall, renal tubule atrophy and lumen stenosis with some necrosis of renal tubules, protein tubule and cell tubules, increase of some glomerular mesangial matrix and hyperplasia of fibrous tissue in the model group, which was re-latively milder in the medication and 3 EA groups.
Conclusion: EA of BL23 and BL17 can reduce the blood pressure in SHR, which may be related to its function in down-regulating expression of TIMP-1, PAI-1 and α-SMA proteins.
Keywords: Alpha smooth muscle actin; Electroacupuncture; Plasminogen activator inhibitor 1; Renal fibrosis; Spontaneous hypertension rats; Tissue inhibitors of metalloproteinase-1.