OBJECTIVETo observe the preventive effect different compatibilities of Ramulus Cinnamomi (RC) and peony in Guizhi Decoction (GD) on diabetic cardiac autonomic neuropathy (DCAN).

METHODSTotally 60 male rats were randomly divided into 5 groups, i.e., the blank control DM group, the model group, the methycobal group, the 1:1 (RC/peony) Guishao group, the 2:1 Guishao group, and the 1:2 Guishao group, 10 in each group. Rats were pretreated with corresponding drugs for 1 week, and then induced diabetes by intraperitoneal injection of STZ. Drugs were administrated by gastrogavage for 4 more weeks after STZ-injection. Enzyme-linked immunosorbent assay (ELISA) was employed to detect levels of tyrosine hydroxylase (TH), choline acetyltransferase (CHAT), nerve growth factor. (NGF), and ciliary neurotrophic factor (CNTF) in myocardial homogenates.

RESULTSAfter 4-week modeling, body weight (BW) was obviously lower, but blood glucose (BG) was higher in STZ rats than in rats of the blank control DM group. There was no statistical difference in BW or BG among the 5 groups (P >0.05). Compared with the blank control group, TH, TH/CHAT, and NGF in left ventricle and ventricular septum increased, CHAT and CNTF increased in the model group (P < 0.05, P < 0.01). Compared with the model group, TH and TH/CHAT in left ventricle decreased (P < 0.05, P < 0.01), CNTF in left ventricle increased (P < 0.05), CHAT in left ventricle and ventricular septum increased (P < 0.05, P < 0.01) in the methycobal group. TH and TH/CHAT in left ventricle and ventricular septum decreased, CNTF in left ventricle and ventricular septum increased (P < 0.05, P < 0.01), CHAT in left ventricle and ventricular septum increased (P < 0.01), NGF in ventricular septum decreased (P < 0.01) in the 1:1 Guishao group. TH/CHAT in left ventricle decreased (P < 0.01), CHAT and CNTF in left ventricle and ventricular septum increased (P < 0.05, P < 0.01) in the 1:2 Guishao group. Compared with the methycobal group, CHAT in left ventricle decreased, TH and TH/CHAT in left ventricle increased in the 2:1 Guishao group (P < 0.05, P < 0.01). TH and TH/CHAT in ventricular septum decreased (P < 0.05), CHAT and CNTF in left ventricle and ventricular septum increased (P < 0.05, P < 0.01) in the 1:1 Guishao group. Compared with the 1:2 Guishao group and the 2:1 Guishao group, CHAT in left ventricle increased, TH/CHAT in left ventricle decreased, TH and TH/CHAT in ventricular septum decreased, CHAT in ventricular septum increased, CNTF in left ventricle and ventricular septum also increased in the 1:1 Guishao group (all P < 0.01).

CONCLUSIONSSTZ model rats had autonomic neural injury, manifested as lowered vagal nerve activity and hyperactive sympathetic nerves. GD could effectively suppress hyperactive cardiac sympathetic nerves and protect the vagus. Besides, GD (1:1) showed the optimal effect in regulating the balance of cardiac autonomic nerves and could be used in early prevention of DCAN.