AIM:To investigate the efficacy and potential mechanism of Xiaotan Tongfu granules(XTTF)in stress ulcers.METHODS:One hundred sixty rats were randomly divided into 4 groups(n=10)as follows:the model group(MP group),the control group(CP group),the ranitidine group(RP group)and the XTTF granule group(XP group).Rats in the MP group received no drugs,rats in the CP group received 0.2 mL of a 0.9%sodium chloride solution via oral gavage,and rats in the RP and XP groups received the same volume of ranitidine(50 mg/kg)or XTTF granule(4.9 g/kg).The cold-restraint stress model was applied to induce stress ulcers after 7 consecutive days of drug administration.Afterwards,rats were sacrificed at 0,3,6 and24 h.Gastric pH was measured by a precise pH meter;gastric emptying rate(GER)was measured by using a methylcellulose test meal;myeloperoxidase activity(MPO),macrophage migration inhibitory factor(MIF),proliferating cell nuclear antigen(PCNA),and heat shock protein 70(HSP70)were measured by immunohistochemical staining;and mucosal cell apoptosis was measured by transferase dUTP nick end labeling.RESULTS:In the cold-restraint stress model,the development of stress ulcers peaked at 3 h and basically regressed after 24 h.Gastric lesions were significantly different in the RP and XP groups at each time point.Interestingly,although this index was much lower in the RP group than in the XP group immediately following stress induction(7.00±1.10 vs 10.00±1.79,P<0.05.Concerning gastric pH,between the RP and XP groups,we detected a statistically significant difference immediately after stress induction(0 h:4.56±0.47 vs 3.34±0.28,P<0.05)but not at any of the subsequent time points.For GER,compared to the RP group,GER was remarkably elevated in the XP group because a statistically significant difference was detected(3 h:46.84±2.70 vs 61.16±5.12,P<0.05;6 h:60.96±6.71 vs 73.41±6.16,P<0.05;24 h:77.47±3.17 vs 91.31±4.34,P<0.05).With respect to MPO and MIF,comparisons between the RP and XP groups revealed statistically significant differences at 3 h(MPO:18.94±1.20 vs 13.51±0.89,P<0.05;MIF:150.67±9.85 vs 122.17±5.67,P<0.05)and 6 h(MPO:13.22±1.54 vs 8.83±0.65,P<0.05;MIF:135.50±9.46 vs 109.83±6.40,P<0.05).With regard to HSP70,HSP70 expression was significantly increased in the RP and XP groups at 3 and 6 h compared to the MP and CP groups.In addition,comparing the RP and XP groups also showed statistically significant differences at 3 and 6 h.The expression of PCNA was higher in the RP and XP groups 3 h after stress induction.Between these two groups,small but statistically significant differences were observed at all of the time points(3 h:69.50±21.52 vs 79.33±15.68,P<0.05;6 h:107.83±4.40 vs 121.33±5.71,P<0.05;24 h:125.33±5.65 vs 128.50±14.49,P<0.05)except 0 h.With regard to apoptosis,the apoptotic activity in the RP and XP groups was significantly different from that in the MP and CP groups.The XP group exhibited a higher inhibition of cell apoptosis than the RP group at3 h(232.58±24.51 vs 174.46±10.35,P<0.05)and6 h(164.74±18.31 vs 117.71±12.08,P<0.05).CONCLUSION:The Xiaotan Tongfu granule was demonstrated to be similar to ranitidine in preventing stress ulcers.It exhibited multiple underlying mechanisms and deserves further study. AIM: To investigate the efficacy and potential mechanism of Xiaotan Tongfu granules (XTTF) in stress ulcers. METHODS: One hundred sixty rats were randomly divided into 4 groups (n = 10) as follows: the model group (MP group), the control group (CP group), the ranitidine group (RP group) and the XTTF granule group (XP group). Rats in the MP group received no drugs, rats in the CP group received 0.2 mL of a 0.9% sodium chloride solution via oral gavage , and rats in the RP and XP groups received the same volume of ranitidine (50 mg / kg) or XTTF granule (4.9 g / kg). The cold-restraint stress model was applied to induce stress ulcers after 7 consecutive days of drug administration . Afterwards, rats were sacrificed at 0,3,6 and 24 h. Gastric pH was measured by a precise pH meter; gastric emptying rate (GER) was measured by using a methylcellulose test meal; myeloperoxidase activity (MPO), macrophage migration inhibitory factor (MIF), proliferating cell nuclear antigen (PCNA), and heat shock protein 70 (HSP70) were measured by immunoh istochemical staining; and mucosal cell apoptosis was measured by transferase dUTP nick end labeling. RESULTS: In the cold-restraint stress model, the development of stress ulcers peaked at 3 h and basically regressed after 24 h. Genetic lesions were significantly different in the RP and XP groups at each time point. Interestingly, although this index was much lower in the RP group than in the XP group immediately following stress induction (7.00 ± 1.10 vs 10.00 ± 1.79, P <0.05.Concerning gastric pH, between the RP and XP groups, we detected a statistically significant difference immediately after stress induction (0 h: 4.56 ± 0.47 vs 3.34 ± 0.28, P <0.05) but not at any of the subsequent time points. For GER, compared to the RP group, GER was remarkably elevated in the XP group because of a significant difference was detected (3 h: 46.84 ± 2.70 vs 61.16 ± 5.12, P <0.05; 6 h: 60.96 ± 6.71 vs 73.41 ± 6.16, P <0.05; 24 h: 77.47 ± 3.17 vs 91.31 ± 4.34, P <0.05) .With respect to MPO and MIF, comparisons between the RP and XP groups(MPO: 18.94 ± 1.20 vs 13.51 ± 0.89, P <0.05; MIF: 150.67 ± 9.85 vs 122.17 ± 5.67, P <0.05) and 6 h (MPO: 13.22 ± 1.54 vs 8.83 ± 0.65, P <0.05; MIF: 135.50 ± 9.46 vs 109.83 ± 6.40, P <0.05) .With regard to HSP70, HSP70 expression was significantly increased in RP and XP groups at 3 and 6 h compared to the MP and CP groups. , comparing the RP and XP groups also showed statistically significant differences at 3 and 6 h. The expression of PCNA was higher in the RP and XP groups after 3 h after stress induction. Both groups were smaller statistically significant differences were observed at all of the time points (3 h: 69.50 ± 21.52 vs 79.33 ± 15.68, P <0.05; 6 h: 107.83 ± 4.40 vs 121.33 ± 5.71, P <0.05; 24 h: 125.33 ± 5.65 vs 128.50 ± 14.49, P < except 0 h.With regard to apoptosis, the apoptotic activity in the RP and XP groups was significantly different from that in MP and CP groups. XP group exhibited a higher inhibition of cell apoptosis than the RP gr oup at 3 h (232.58 ± 24.51 vs 174.46 ± 10.35, P <0.05) and 6 h (164.74 ± 18.31 vs 117.71 ± 12.08, P <0.05) .CONCLUSION: The Xiaotan Tongfu granule was demonstrated to be similar to ranitidine in preventing stress ulcers. It showed multiple underlying mechanisms and deserves further study.