Objective To observe the effect of electroacupuncture(EA) of “Zusanli”(ST36)

“Sanyinjiao”(SP6) and “Liangmen”(ST21) on gastrointestinal motility

blood glucose content and expression of autophagy-related proteins 1 light chain 3(LC3)

p62

phosphatidyli-nositol-3 kinase(PI3 K)

protein kinase B(Akt)

p-Akt and mammalian target protein of rapamycin(mTOR) of interstitial cells of Cajal(ICCs) in the cultured gastric antrum cells in diabetic gastroparesis(DGP) rats

so as to reveal its mechanisms underlying improvement of DGP. Methods A total of 45 Sprague Dawley(SD) rats were randomly divided into blank control

model

EA

medication(3-methyladenine

3-MA) and EA+3-MA groups

with 9 rats in each group. The DGP model was established by intraperitoneal injection of 2% streptozotocin(STZ) combined with high-fat and high sugar diet for 8 weeks. The gastric emptying rate was measured by using gavage of phenol red(to measure the propelling length of the phenol red/total length of small intestine ×100%). The symptom score(mental state

coat color and luster

behavior and activity

stool traits) of rats was observed every week and the blood glucose content was measured by using a glucometer. EA(20 Hz/100 Hz

2 mA) was applied to unilateral ST36

SP6 and ST21 alternatively for 15 min

once daily

5 days a week for 3 weeks. Rats of the 3-MA and 3-MA+EA groups received intraperitoneal injection of 3-MA(30 mg·kg

(-1)

·d(-1)·d

(-1)

10 mg/mL)

once daily

5 days a week for 3 weeks. After 15 days' intervention

the rats were operated for gastric emptying rate test

specimen collection

isolation

and culture of primary ICCs. The expression levels of microtubule associated protein LC3

p62

PI3 K

Akt

p-Akt and mTOR of ICCs of cultured gastric antrum cells were detected using Western blot

and the number of autophagosomes in ICC of gastric antrum was observed under transmission electron microscope. Results Compared with the blank control group

the symptom score

blood glucose

and the expression levels of p62

class Ⅰ PI3 K

Akt

p-Akt and mTOR proteins were increased significantly(P

<

0.01)

while the gastric emptying rate and ratio of LC3Ⅱ/LC3Ⅰ and the expression level of class Ⅲ PI3 K protein were significantly decreased(P

<

0.05

P

<

0.01) in the model group. In comparison with the model group

the increase of symptom score

blood glucose

and expression levels of p62

class Ⅰ PI3 K

Akt

p-Akt and mTOR proteins and the decrease of gastric empty rate and LC3Ⅱ/LC3Ⅰ ratio and the expression level of class Ⅲ PI3 K protein were all reversed in both EA and EA+3-MA groups(P

<

0.05

P

<

0.01)

rather than in the 3-MA group. In addition

3-MA also reversed modeling-induced increase of class Ⅰ PI3 K

Akt

p-Akt and mTOR proteins expression(P

<

0.01). No significant differences were found between the EA and EA+3-MA in downregulating the levels of symptom score and blood glucose content

and in upregulating gastric empty rate(P

>

0.05). The effect of EA was notably superior to that of EA+3-MA in upregulating the ratio of LC3Ⅱ/LC3Ⅰ and the expression level of class Ⅲ PI3 K protein

and in downregulating the expression of p62

class Ⅰ PI3 K

Akt

p-Akt and mTOR proteins(P

<

0.05

P

<

0.01). The findings of transmission electron microscopy showed obvious swelling

breakage of some mitochondrial cristae in the ICC cells of antrum and no autophagosomes in the model group and 3-MA group

which was milder in the damage of mitochondrial cristae and marked increase in the autophagosomes in both EA and EA+3-MA groups. Conclusion EA can improve the gastrointestinal motility and symptoms in DGP rats

which may be related to its functions in downregulating PI3 K/Akt/mTOR signaling to promote autophagy level of ICC.