ABSTRACT
BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) and BMSCs-derived exosomes have similar functions, but the regulatory mechanism underlying the release of exosomes is still unclear. OBJECTIVE: To investigate the role of GW4869, an inhibition of neutral sphingomyelinase 2, in the release of exosomes in BMSCs and the influence of GW4869 on BMSCs proliferation. METHODS: Rat BMSCs were divided into three groups: normal control group, 24-hour GW4869 treatment group and withdrawal of GW4869 for 24 hours group (24-hour GW4869 treatment followed by 24-hour successive culture with drug withdrawal). Cultured cells were collected to extract exosomes by ultracentrifugation. Western blot was used to detect exosome-associated proteins CD63 and tumor susceptibility gene 101 (TSG101). The concentration and size distribution of exosomes were measured using nanoparticle tracking analysis. BCA was used to test the level of total proteins in exosomes. Live cell imaging system was used to observe the influence of GW4869 on BMSCs proliferation. RESULTS AND CONCLUSION: (1) Western blot results showed that exosomes expressed marker proteins such as CD63, TSG101. (2) Findings from the nanoparticle tracking analysis confirmed that the size of released exosomes was about 114 nm. (3) Significantly reduced release of exosomes was found in the two treatment groups compared with the normal control group (P < 0.01), but there was no significant difference between 24-hour GW4869 treatment group and withdrawal of GW4869 for 24 hours group (P > 0.05). (4) No significant difference in the proliferation of BMSCs was found among the three groups (P > 0.05). To conclude, 24-hour W4869 can inhibit the release of exosomes by BMSCs and this inhibitory effect is still sustained within 24 hours after drug withdrawal. However, GW4869 has no influence on the proliferation of BMSCs.
ABSTRACT
Objective To investigate the assessment methods and mechanisms of nonsteroidal antiinflammatory drugs (NSAID)-induced injury in rat small intestinal epithelial barrier,and to explore the protective effects of mucosal protective agents and antacids on it.Methods A total of 96 rats were evenly divided into the morphologic observation group and the mechanism research group,and 48 in each group.Then each group was evenly divided into eight subgroups:the healthy control group,the model group (model established with indomethacin),the teprenone prevention group,the rabeprazole prevention group,the treatment control group,the teprenone treatment group,the rabeprazole treatment group and the teprenone and rabeprazole combined group (combined group),six in each group.Exfoliated cells gap density of small intestine of each subgroup was determined by confocal laser endomicroscopy.Serum level of tumor necrosis factor-α (TNF-α)was measured with enzyme-linked immunosorbent assay (ELISA). The expression of nuclear factor-κB (NF-κB),caspase-3,zonula occludens-1 (ZO-1 )and occludin at protein level was detected by Western blotting.The LSD-t test or Hamhane′s T2 test was performed for statistical analysis.Results The exfoliated cells gap densities of the teprenone prevention group and the rabeprazole prevention group were (57.43 ± 24.55 )/1 000 and (59.80 ± 21 .14 )/1 000,respectively, which were both lower than that of the model group ((110.93±50.58)/1 000),and the differences were statistically significant (t= 53.50 and 54.13,both P < 0.01 ).The exfoliated cells gap density of the combined group was (40.53 ±15 .39)/1 000,which was lower than that of the treatment control group ((93.80±40.65 )/1 000 ),and the difference was statistically significant (t =44.27,P <0.01 ).The serum levels of TNF-α of the teprenone prevention group and the rabeprazole prevention group were (25 .80±8.97)ng/L and (22.74 ±7.15 )ng/L,repsectively,which were both lower than that of the model group ((44.48 ± 7.42 )ng/L),and the differences were statistically significant (t = 18.68 and 21 .74,both P <0.01 ).The serum level of TNF-αof the combined group ((13.66 ±4.98)ng/L)was lower than that of the treatment control group ((24.67±6.70)ng/L),and the difference was statistically significant (t = 9.02,P < 0.01 ).The caspase-3 levels of teprenone prevention group and rabeprazole prevention group were 1 .47 ±0.35 and 1 .58 ±0.34,and the NF-κB levels of these two groups were 1 .27±0.14 and 1 .21 ± 0.10,respectively.Compared with those of model group (2.44 ± 0.45 and 1 .69±0.13),the differences were statistically significant (t =0.97,0.86,0.42 and 0.48,respectively, all P <0.01 ).The levels of caspase-3 and NF-κB of the combined group were 0.66±0.06 and 0.44 ± 0.21 ,respectively,which were lower than those of the treatment control group,and the differences were statistically significant (t=0.34 and 0.56,both P <0.01).The expressions of occludin at protein level of the teprenone prevention group and the rabeprazole prevention group were 0.69 ±0.16 and 0.74 ±0.11 , and the levels of ZO-1 were 0.81 ± 0.08 and 0.84 ± 0.12.Compared with those of the model group (0.45 ±0.22 and 0.64±0.07 ),the differences were statistically significant (t =0.24,0.29,0.17 and 0.21 ,respectively,all P <0.01 ).The levels of occludin and ZO-1 of the combined group were 2.50 ± 0.46 and 1 .76±0.18,which were higher than those of the treatment control group,and the differences were statistically significant (t =1 .50 and 0.76,both P <0.01 ).Conclusions The exfoliated cells gap density may be a valuable indicator to predict the degree of inflammation response and permeability of epithelial barrier as well as to evaluate efficacy of medication.Teprenone and rabeprazole have prevention and treatment effects on NSAID-induced injury in rat small intestine.