Reversal Mechanism Of Precancerous Lesions Of Gastric Cancer Based On Bcl-2 And Beclin-1 Tumor-related Genes And Research On Rat Model

Objective:To observe the pathological effects of N-methyl-N'-nitro-N-ntrosoguanidine(MNNG)through different routes of administration and at different doses on gastric mucosal tissues in gastric precancerous lesions of SD rats,and to explore the mechanism of the prescription of dissipating phlegm and eliminating blood stasis in reversing precancerous lesions of gastric cancer.Methods:A total of 150 SD male rats weighing 80-100g were randomly divided into 6 groups,including blank control free-drink group,blank control group by gastrogavage,MNNG low concentration group,MNNG moderate concentration group,MNNG high concentration group and MNNG gastrogavage group,with 25 rats in each group.Rats in the low-,moderate-and high-concentration groups were administrated with free drink of 50?g/mL,100p.g/mL and 150?g/mL MNNG respectively,combined with high concentration of sodium in the drinking water(15%Nacl drinking),irregular diet and ranitidine processed feed to construct the experimental model.Meanwhile,on the basis of treatment in the low concentration group,rats in the gastrogavage group were given 0.017mol/L MNNG solution daily(Calculation of the amount of intragastric administration according to the weight of rats in different periods).Following 28W of treatment,the general condition and histopathological changes of rats were compared in each group.According to the successful initial modeling,another modeling for 28W was used carried out by applying the method in the moderate concentration group with the highest success rate.After successful modeling,rats with the similar body weight were selected and divided into the model group,low concentration group of traditional Chinese medicine(TCM),moderate concentration group of TCM and high concentration group of TCM subject to intervention for 16 weeks,with 15 rats in each group.Subsequently,the general condition and pathological changes of gastric mucosa were observed in rats,and the expression of Bcl-2 in gastric mucosa was detected by immunohistochemistry.Besides,Western blot was used to detect the expression level of autophagy related protein Beclin-1 after treatment.Results:In the low concentration group,there were more changes in squamous epithelium with an incidence rate of 28%,and only 11 rats showed inflammatory changes.Furthermore,the incidence of atrophy and intestinal metaplasia was 65.2%in the moderate concentration group,and only few cases manifested squamous epithelium changes.In the high concentration group,rats showed atrophy,intestinal metaplasia,squamous metaplasia and canceration(squamous cell carcinoma),with the canceration rate and induction rate being 33.4%and 85.7%respectively.In addition,rats in the gastrogavage group developed atrophy,intestinal metaplasia,squamous metaplasia and canceration,with an induction rate of 84.2%.After the intervention treatment of TCM,the expression of Bcl-2 was significantly lower in the gastric mucosa of each dose group with the prescription of dissipating phlegm and eliminating blood stasis than that of the model group,and the difference was statistically significant(P<0.01).Besides,the expression was obviously improved in the moderate and high concentration groups using the prescription of dissipating phlegm and eliminating blood stasis when compared to that of the low concentration group.Furthermore,the expression level of autophagy related protein Beclin-1 was lower in each dose group with the prescription of dissipating phlegm and eliminating blood stasis than that in model group,indicating statistically significant difference(P<0.01).Meanwhile,the expression was obviously better in the moderate and high concentration groups using the prescription of dissipating phlegm and eliminating blood stasis than that of the low concentration group.Conclusion:Under the induction of MNNG,combined feeding of ranitidine,irregular diet,high concentration of sodium in the drinking water and gastrogavage,rat model characterized by atrophy,intestinal metaplasia,atrophy and intestinal metaplasia was successfully induced.Rats in the MNNG free-drink high concentration group and the MNNG gastrogavage group showed relatively high induction rate and appear canceration.The prescription of dissipating phlegm and eliminating blood stasis can significantly improve the histopathological condition of gastric mucosa in rats and reverse the precancerous lesion of gastric cancer.The reversal mechanism may be at work through regulation of cell cycle by down regulating the expression of Bcl-2 and Beclin-1.