To study the effect of electroacupuncture at Zusanli point on gastric emptying rate and mucosal blood flow after oral rehydration of full thickness scalded rats.

Using random number table method, 120 rats were divided into 5 groups: sham+ intragastric rehydration group(GR group), scald+ intragastric rehydration group(SGR group), scald+ electro-acupuncture+ intragastric rehydration group(SGR+ EA group), vagotomy+ scald+ intragastric rehydration group(VGX+ SGR group) and vagotomy+ scald+ electro-acupuncture+ intragastric rehydration group (VGX+ SGR+ EA group), with 24 rats in each group. In 1 000 mL of sterile distilled water, 3.5 g of sodium pyruvate, 3.5 g of sodium chloride, 1.5 g of potassium chloride, and 20.0 g of glucose were added, sodium pyruvate oral rehydration salt (Pyr-ORS) was configured, and the pH was adjusted to 7.35. After the rats were anesthetized, the carotid artery, femoral vein, and femoral artery were separated and the catheterization was did. The scalded rats were scalded with boiling water (100 ℃, 15 s) for about 35% total body surface area (TBSA) of the back, and the scalded rats were immersed in warm water (37 ℃, 15 s). Immediately after the scald, each rat was given a subcutaneous injection of 0.5 mL of 0.9% sodium chloride solution and 500 mL of buprenorphine for pain relief. Pyr-ORS was immediately infused via a gastric tube using an infusion pump for 1 h. Rats in the VGX+ SGR group and the VGX+ SGR+ EA group underwent bilateral vagus nerve resection before burns. In the SGR+ EA and VGX+ SGR+ EA groups, Zusanli point was selected for acupuncture and connected to an electroacupuncture instrument. The intensity was 2 mA, 2 to 100 Hz, and the acupuncture depth was 7 mm. After rehydration, the electroacupuncture was continued for 0.5 h. The gastric emptying rate and gastric mucosal blood flow of each group were measured at 2 and 4 h after scald. Data were compared using one-way analysis of variance and t test.

The gastric emptying rates of rats in the SGR group, SGR + EA group, VGX + EA group, and VGX + SGR + EA group [2 h: (16.5±3.2)%, (22.6±3.7)%, (13.6±3.0)%, (14.2±3.2)%; 4 h: (12.9±2.4)%, (17.1±2.3)%, (10.8±2.7)%, (12.7±2.5)% were lower than those of rats in the GR group [2 h: (45.9±4.6)%; 4 h: (42.4±5.7)%], the differences were statistically significant [2 h: (t=18.18, 13.67, 20.37, 19.60; with P values below 0.05); 4 h: (t=28.29, 24.71, 28.67, 27.96; with P values below 0.05). The gastric emptying rates of rats in the SGR+ EA group was higher than those of rats in the SGR group, VGX+ SGR group and VGX+ SGR+ EA group, and the differences were statistically significant [2 h: (t=4.32, 6.54, 5.94; with P values below 0.05); 4 h: (t=4.38, 6.15, 4.49; with P values below 0.05)]. Gastric mucosal blood flow of rats in the SGR group, SGR+ EA group, VGX+ EA group, and VGX+ SGR+ EA group at 2 and 4 h after scald [2 h: (54.0±7.3), (74.6±8.7), (42.0±5.5), (45.2±6.2) BPU, 4 h: (46.0±6.8), (65.6±10.1), (37.8±5.6), (42.7±6.4) BPU] were significantly lower than the GR group [2 h: (142.0±18.1) BPU; 4 h: (127.4±16.5) BPU], the differences were statistically significant [2 h: (t=15.67, 11.67, 18.35, 17.56; with P values below 0.05); 4 h: (t=15.80, 11.07, 17.81, 16.58; with P values below 0.05)]; the gastric mucosal blood flow of rats in the SGR+ EA group compared with SGR group, VGX+ SGR group and VGX+ SGR+ EA group, the difference were statistically significant[2 h: (t=6.28, 10.97, 9.53; with P values below0.05); 4 h: (t= 5.58, 8.33, 6.63; with P values below 0.05)].

Electro acupuncture at Zusanli point can promote the rate of gastric emptying, increase gastric mucosal blood flow, and improve the efficacy of oral rehydration in full thickness scalded rats. The mechanism may be related to the stimulation of the vagus nerve.

Electroacupuncture; Rats; Fluid therapy; Vagus nerve; Scald; Zusanli; Gastric emptying