Protective effect of the daming capsule on impaired baroreflexes in STZ-induced diabetic rats with hyperlipoidemia

BMC Complementary and Alternative Medicine

Research Article

Li-Hua Sun¹  Guan-Yi Lu¹  Bao-Feng Yang¹  Jing Ai¹  Guo-Fen Qiao¹  Rong Zhang¹  Chao Sun¹  Ning Wang¹  Li-Hong Wang² 

[1] Department of Pharmacology, and the State-Province Key Laboratory of Biomedicine and Pharmaceutics, Harbin Medical University, 150081, Harbin, P.R., China;Endocrinology and Metabolism Department of the Second Affiliated Hospital, Harbin Medical University, 150086, Harbin, P.R., China;

关键词: GABAA Receptor;    Mean Arterial Blood Pressure;    Baroreflex Sensitivity;    Diabetes Mellitus Group;    Baroreflex Control;   

DOI  :  10.1186/1472-6882-10-80

 received in 2010-04-16, accepted in 2010-12-22,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundThe Daming capsule (DMC) is a traditional Chinese medicine used to treat hyperlipoidemia. Both clinic trials and studies on animal models have demonstrated that DMC is beneficial against diabetic symptoms. Impairment of the baroreflex can cause life-threatening arrhythmias and sudden cardiac death in patients with diabetes mellitus (DM). This study was designed to elucidate the effects of DMC on baroreflexes in streptozocin (STZ)-induced diabetic rats with hyperlipoidemia.MethodsWistar rats were randomly divided into three groups: untreated controls, rats pretreated STZ and high lipids (a diabetes model or DM rats), and DM rats treated with DMC. The baroreflex sensitivity was examined during intravenous injection of phenylephrine (PE) or sodium nitroprusside (SNP) and quantified by the change in heart rate over the change in mean arterial blood pressure (ΔHR/ΔMABP). Morphological remodeling of baroreceptors was analyzed by transmission electron microscopy (TEM). The mRNA levels and expression of GluR2 and a GABAA receptor subunit were measured by quantitative RT-PCR and Western blotting.ResultsCompared to untreated DM rats, DMC significantly elevated the ratio of ΔHR/ΔMABP by enhancing the compensatory reduction in HR (-ΔHR) in response to PE-induced hypertension (+ΔMABP) (P < 0.05). In the presence of SNP, DMC increased the ΔMABP (P < 0.05). In addition, DMC markedly shortened the duration of blood pressure changes elicited by PE or SNP in DM rats compared to the untreated DM group (P < 0.05). Electron microscopy revealed disrupted myelin sheaths, swollen ER, and lysed mitochondria in the nucleus ambiguous (NAm) DM rats. These signs of neuropathology were largely prevented by treatment with DMC for 30 days. Treatment with DMC elevated both mRNA and protein level of GluR2 in the NAm of DM rats, but had no effect on GABAA receptor expression.ConclusionThe Daming capsule partially reversed the parasympathetic baroreflex impairment observed in STZ-induced diabetic rats with hyperlipoidemia. Treatment with DMC also prevented the degeneration of neurons and myelinated axons in the brain stem NAm and reversed the down-regulation of GluR2 mRNA. Rescue of NAm function may contribute to the medicinal properties of DMC in diabetic rats.

【 授权许可】

CC BY   
© Ai et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.