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Objective:To compare the effect and biotoxicity of tert-butyl acetate (TBA) and ethyl butyrate (EB) on stone dissolution in vitro.Methods:Ten gallstone samples from patients with multiple gallbladder stones were selected and the cholesterol content was analyzed by HPLC. Stone dissolution tests of TBA and EB were performed on cholesterol gallstone in vitro, and the weight of stone at each time point was recorded, meanwhile, methyl tert-butyl ether (MTBE) was used as the control. The inhibitory effects of MTBE, TBA and EB on proliferation of human normal liver cell line LO2 were analyzed by cell proliferation inhibition assay. Flow cytometry was used to analyze the effects of MTBE, TBA and EB on the early and late apoptosis of LO2 cells, and the changes of reactive oxygen species level in LO2 cells were also analyzed.Results:Of the 10 gallbladder gallstones, 6 were cholesterol gallstones and 4 were non-cholesterol gallstones. Stone dissolution experiment showed that the remaining stones of MTBE, TBA and EB groups were (47.83±3.84)%, (58.12±4.53)% and (75.75±4.61)% 30 minutes later. The remaining stones were (18.38±6.47)%, (33.82±6.22)% and (56.38±3.91)% 90 minutes later. MTBE had the best stone dissolution effect in vitro, the stone dissolution effect of TBA was slightly weaker than MTBE, and the stone dissolution effect of EB was relatively weak in all ( P<0.05). The cell proliferation inhibition experiment showed that the cell viability of the control group, MTBE group and TBA group were (100.00±4.46)%, (96.79±4.32)% and (93.72±3.51)%, respectively, and there were no significant differences among the three groups ( P>0.05). However, the cell viability of EB group (87.57±5.29)% was lower than the above three groups, and the differences were statistically significant ( P<0.001). The early apoptosis and late apoptosis of the control group were (1.67±0.15)% and (1.27±0.06)%, respectively. EB induced early apoptosis (15.90±0.53)% ( P<0.001) and late apoptosis (5.13±0.76)% ( P<0.05). However, MTBE and TBA had no significant effect on cell apoptosis ( P>0.05). Compared with control group, MTBE, TBA and EB all significantly inhibited the level of reactive oxygen species ( P<0.05), and the inhibitory effect of EB was the most obvious. Conclusions:TBA has good stone dissolution effect and biosafety for gallbladder cholesterol stones in vitro, while EB has relatively poor performance. TBA is a potential drug for gallstone dissolution.
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Objective To investigate the expressions of peroxisome proliferator activated receptor-γ (PPAR-γ) and β-catenin in 5-aminosalicylic acid （ASA) intervened colitis carcinogenesis mouse model induced by azoxymethane (AOM) and dextran sulfate sodium (DSS).Methods Thirtysix BALB/c mice were evenly divided into control group,model group,and intervention group.For model group and intervention group,mice were intraperitoneally injected with AOM (10 mg/kg) one day before experiment,then drank 4％ DSS solution freely for one week and followed with common drinking water for another two weeks.Taking 4％ DSS solution and common drinking water repeated for three cycles.For intervention group,5-ASA (150 mg/kg) was given from three days before experiment to the end of research.For control group,mice were intraperitoneally injected with 0.9％NaCl solation and then given common drinking water for nine weeks.The symptoms of the disease were monitored in mice and pathological changes of tissues were evaluated at the end of first week and ninth week.At the end of the ninth week,the expressions of PPAR-γ,β-catenin protein and PPAR-γat mRNA level in colon tissue were detected.The data were analyzed by t test.Results The colitis disease activity index (DAI) index of intervention group was 1.81 ±0.59 after drinking DSS solution for one week and the number of tumor was 4.11 ± 1.05 at the end of the ninth week,both were significantly lower than those of model group (2.47 ± 0.53 and 9.71±2.29 respectively,t=2.88 and 6.55; both P＜0.01).The expression of PPAR-γ at protein level (2.11±1.36) and mRNA level (1.45±0.10) in colon tissue of intervention group significantly increased compared with those of model group (0.43±0.53 and 0.57±0.08 respectively,t=3.07 and 18.99,both P＜0.01).There was no significant difference of β-catenin expression among groups (P＞0.05).Conclusions 5-ASA can efficiently improve the inflammatory reaction and tumor load in AOM and DSS induced colitis carcinogenesis mouse model,and at the same time can promote the expression of PPAR-γ in colon.However,there was no significant influence on the expression of β-catenin.
