To investigate the protective mechanism of Sanqi（Panax notoginseng）saponins on gastric mucosa in mice with gastric precancerous lesions combined with myocardial ischemia-reperfusion injury.

Eighty-five C57BL/6 mice were divided into 6 groups：blank control group（C group）, model group（M group）, high, medium and low dose groups of Sanqi（Panax notoginseng）saponins（SH, SM, SL groups）, and positive control group（R group）. Except for group C which had 10 animals without modeling, all the other groups had 15 animals in each. A mouse model of gastric precancerous lesions was established by chemical induction and fasting every other day for 310 days. On the 311th day, the model mice underwent the myocardial ischemia-reperfusion injury surgery to establish a mouse model of gastric precancerous lesions combined with myocardial ischemia-reperfusion injury. SH, SM and SL groups were given Sanqi（Panax notoginseng）saponins with the dose of 300, 150, 75 mg/kg, respectively. R group was given rapamycin（1.5 mg/kg）, and C and M groups were given the equal amounts of distilled water. During the modeling of gastric precancerous lesions, the drug was given once a day by intragastric administration. After the completion of myocardial ischemia-reperfusion injury modeling, the drug was continued to administer once a day for 1 week. HE and AB-PAS staining were used to observe the pathological changes of gastric mucosa. TTC staining was used to observe the heart infarction area and weigh it, and Western blot was used to analyze the expressions of autophagy related proteins.

Histopathological analysis showed that the intrinsic layer of the gastric tissue of mice in group M was arranged in a loose manner, the cell atrophy cavity and trace inflammatory infiltration were evident, the local nucleus necrosis was ablated, the amount of purplish red particles in the epithelial cells was significantly reduced, and there was obvious cell shedding, while the gastric histopathology of mice in SH and R groups was significantly improved. The TTC staining and tissue weighing results showed that compared with the M group, the SH group, SM group, SL group and R group had significantly reduced heart infarction and ischemic area and weight（P < 0.001）. The Western blot results showed that compared with those of the M group, the expressions of LC3 Ⅱ/LC3 Ⅰ, Beclin-1 and ATG5 proteins in the gastric tissues of SH group, SM group and R group mice were up-regulated（P < 0.05 or P < 0.01）, while the expressions of p62, AKT, p-AKT, mTOR and p-mTOR proteins were down-regulated（P < 0.05 or P < 0.01）.

Sanqi（Panax notoginseng）saponins can prevent precancerous lesions and alleviate myocardial ischemia-reperfusion injury in mice by inhibiting the PI3K/AKT/mTOR signaling pathway and activating autophagy.