Protective Effect and Mechanism of Kuntai Capsule on Angiotensin II -Induced Hypertension in Ovariectomized Rats

Abstract

Objective: To explore the protective effect and mechanism of Kuntai (KT) Capsule on angiotensin II (Ang II)-induced hypertension in ovariectomized (OVX) rats.

Methods: Fifty-four rats were randomly divided into 6 groups according to a random number table, 9 in each group: control, OVX sham+Ang II, OVX, OVX+Ang II, OVX+Ang II +E₂, and OVX+Ang II +KT. OVX rats model was constructed by retroperitoneal bilateral ovariectomy. After 4 weeks of pretreatment with KT Capsule [0.8 g/(kg·d) and 17- β -estradiol (E₂, 1.2 mg/(kg·d)] respectively, Ang II was injected into a micro-osmotic pump with a syringe to establish a hypertensive rat model. Blood pressure of rat tail artery was measured in a wake state of rats using a non-invasive sphygmomanometer. Blood pressure changes were compared between the intervention groups (OVX+Ang II +KT, OVX+Ang II +E₂) and the negative control group (OVX+Ang II). Serum malondialdehyde (MDA) level and superoxide dismutase (SOD) activity were detected respectively. The expressions of oxidative stress-related protein superoxide dismutase2 (SOD2) and anti-thioredoxin (TRX), autophagy marker protein [beclin1, light chain (LC) 3 II/I ratio and autophagy canonical pathway protein phosphatidylinositol 3-kinase (PI3K)/serine/threonine kinase (AKT)-mammalian target of rapamycin (mTOR)] were evaluated by Western blotting.

Results: Compared with the OVX+Ang II group, the systolic blood pressure of OVX+Ang II +KT group was significantly lowered (P<0.05) but not the diastolic blood pressure. Besides, SOD2 and TRX protein levels in mycardial tissues were significantly reduced in the OVX+Ang II +KT group compared with the OVX+Ang II group (P<0.05). Oxidative stress serum markers MDA and SOD were down- and up-regulated in the OVX+Ang II +KT group, respectively (P<0.05). Compared with OVX+Ang II group, the levels of cardiac proteins beclin-1 and LC3II/LC3 I in OVX+Ang II +KT group were also up-regulated (P<0.05), and the expression levels of p-PI3K, p-AKT and mTOR protein were down-regulated (P<0.05).

Conclusion: KT could protect blood pressure of Ang II-induced OVX rats by inhibiting oxidative stress and up-regulating protective autophagy.

Keywords: Chinese medicine; Kuntai Capsule; angiotensin II; perimenopausal hypertension.