Epigallocatechin Gallate Protects against MNNG-Induced Precancerous Lesions of Gastric Carcinoma in Rats via PI3K/Akt/mTOR Pathway

Abstract

Objective. To evaluate the therapeutic effect of epigallocatechin gallate (EGCG) on precancerous lesions of gastric carcinoma (PLGC) and to determine whether EGCG protects against PLGC by regulating PI3K/Akt/mTOR pathway. Methods. Twenty-four male Wistar rats were randomly divided into 3 groups: normal control group (NC), PLGC model group (MC), and group of PLGC rats treated with EGCG (MC + EGCG). 1-Methyl-3-nitro-1-nitrosoguanidine (MNNG) and sodium salicylate were combined and used to establish the PLGC rat animal model. The therapeutic effect of EGCG on PLGC was evaluated by body weight and pathological lesions of gastric mucosa in PLGC rats. Quantitative polymerase chain reaction (qPCR) was applied to measure the mRNA expressions of PI3K, Akt, and mTOR. The protein expressions of cleaved caspase-3, PTEN, PI3K, p-PI3K, Akt, p-Akt, p-mTOR, and mTOR were determined by automated western immunoblotting. Results. The body weight decreased in PLGC rats while EGCG significantly increased body weight. The gastric mucosa of PLGC rats exhibited the pathological lesions of atrophy, intestinal metaplasia, and atypical hyperplasia while EGCG could ameliorate the pathological lesions. EGCG could upregulate the expressions of cleaved caspase-3 and PTEN and reduce the expressions of PI3K, Akt, and mTOR. Conclusions. EGCG ameliorated pathological lesions of PLGC and exerted the effect of apoptosis promotion in PLGC rats. The apoptotic pathway triggered by EGCG may be related to inhibition of PI3K/Akt/mTOR pathway. It provided a theoretical basis for the PLGC treatment and gastric cancer prevention.