The Role Of ERK Signal Transduction Pathways In The Development Of Barrett's Esophagus Model

In recent years, the incidence rate of Barrett's esophagus has been rising year by year, and most of Esophageal adenocarcinomas are developed from Barrett's esophagus. Barrett's esophagus is recognized as Esophageal adenocarcinoma's precancerous lesions, however, the specific pathogenesis of Barrett esophagus are not entirely explained clearly.The ccurrence of the Barrett esophagus involves some kinds of biological events and physiological processes, and is closely related to cell excessive proliferation, cell apoptosis frustration, and prosoplasia. Signal pathway plays an important role in disease development. ERK (extracellular signal regulated kinase) is a typical MAPK signal transduction pathway, and exocellular stimulation can make factor receptor and tyrosine kinase receptors stimulate ERK via Ras-Raf- MEK-ERK cascading signals, and the phosphorylated ERK (p-ERK) is translocated to nucleus and phosphorylatied, and activate some of the transcription factors (including CyclinE, c-myc) and so on, and finally starts the relevant target genes transcription to cell proliferation, where CyclinE is an important substrate of ERK signal pathway, and combining CyclinE with CDK2 is a necessary condition to initiate period S in the cell cycle. CyclinE over-expressing can cause the cell cycle disorder and cell excessive proliferation.The study discusses the protein variations in the process of Barrett esophagus by constructing the animal model of Barrett esophagus and detecting the expression level of ERK1/2, p-ERK1/2, and CyclinE in Barrett esophageal tissue. And it provides the theory basis for the research of the pathogenesis of this disease and prevention of Barrett esophagusObjective: To establish a rat reflux esophagitis and Barrett esophagus model in order to study the relationship of ERK1/2, p-ERK1/2, CyclinE with Barrett esophagus.Methods: 1 The male SD rats were randomly divided into operation group (SO group, n = 10); ferralia group (iron group n=10); E esophagoduodenal anastomosis group (EDA group n = 30); EDA plus iron (EDA + Fe group n = 30); Esophagogastroduodenal anastomosis group (EGDA group n = 30 ); EGDA with iron group (EGDA + Fe group n = 30).2 The operation was operated in the fomrer two groups and the last four four groups underwent surgical operation to produe reflux . After 2 weeks,Iron Dextran were injected intraperitoneum of the rats in EDA+Fe group and EGDA+Fe group (30mg/kg,twice per week for 30 weeks). 5 rats of each group were sacrificed at 12 week after operation and others at 32 week, and esophageal samples were taken.3 The expression of ERK1/2,p-ERK1/2,and CyclinE were were exmain- d in nomal esophagus, esophagitis, and Barrett's esophagus by immunohi stochemical staining of S-P.Results:1 The mortality of rats in different operational methods group and ferralia group: the mortality rates of the normal group, ferralia group, EDA group, EDA+Fe group, EGDA group and EGDA+Fe group were 0%, 0%, 26.7%, 30% and 6.7% respectively. There was significant difference in mortality between the rats in EDA group, EDA+FE group, EGDA group and EGDA+Fe group with the rats in normal group and ferralia group.(P<0.05). There was no significant difference in mortality between the rats in EDA group with the rats in EDA+Fe group (P>0.05) and EGDA group with EGDA+Fe group. The mortality between EDA group and EGDA group are quite different. (P<0.05) Many causes of death in EDA group were attributed to anastomostic leakage and infection of abdomino. In EGDA the main causes of death were attributed to pulmonary infection and infection of abdomino.2 12 weeks after operation, 5 rats in normal group, ferralia group, EDA group, EDA+Fe group, EGDA group, and EGDA+Fe group were dead respectively , the incidence rates of inflammation in normal group, ferralia group, EDA group, EDA+Fe group, EGDA group, and EGDA+Fe group were 0%, 40%, 100%,100%,100% and 100% respectively, the incidence rates of hyperplasia in normal group, ferralia group, EDA group, EDA+Fe group, EGDA group, and EGDA+Fe group were 0%, 0%, 20%, 40%, 20% and 40% respectively, and the incidence rates of Barrette esophagitis were 0%, 0%, 20%, 40%, 20% and 40% respectively,To 32 weeks, the further development of lesions in each group, normal group, ferralia group, EDA group, EDA + Fe group, EGDA group, EGDA + Fe group were 0%, 100%, 100%, 100% 100%, 100%, Barrett esophagus incidence rate was 0%,0%,26%,56.5%,23.5%,62.5%。the incidence of Barrett esophagus between EDA group,EDA + Fe group,EGDA group,EGDA + Fe group and normal group,ferralia group was significant difference (p <0.05). EDA and the EDA + Fe group compared the incidence of Barrett esophagus was significant difference (p <0.05). EGDA,EGDA + Fe group compared the incidence of Barrett esophagus was significant difference (p <0.05). the incidence of Barrett esophagus between EDA group and EGDA group was significant difference (p <0.05)3 ERK1/2 in rat normal esophageal squamous epithelium specimens, specimens of reflux esophagitis and Barrett esophagus were expressed mainly in the cytoplasm area, some in the nucleus, the expression level gradually increased, the average optical density values were was 0.0358±0.0020,0.1146±0.0152 and 0.2164±0.0168, the difference was significant (P <0.05)4 p-ERK1/2 in rat normal esophageal squamous epithelium specimens, specimens of reflux esophagitis and Barrett esophagus were expressed mainly in the nucleus area, part of the cytoplasm can also be found, the average optical density values were 0.0262±0.0071,0.0825±0.0095 and 0.1800±0.0095. The difference was significant (P <0.05).5 CyclinE normal esophageal squamous epithelium in the rat specimens, specimens of reflux esophagitis and Barrett esophagus were expressed mainly in the nucleus area, part of the cytoplasm is also visible expression of the average optical density was 0.0228±0.0041 , 0.1045±0.0090 and 0.1937±0.0122, the difference was significant (P <0.05)6 The correlation of relative expression among ERK1/2 and CyclinE was good(r=0.737), The correlation of relative expression among p-ERK1/2 and CyclinE was good(r=0.757)。Conclusion:1 Based on the long-term reflux, the use of excessive ferralia cansignificantly increase the damage of esophagus. The animal models constructed by EDA+Fe & EGDA+Fe can induce the occurrence of Barrett's esophagus. In addition, these two models have no significant difference in the incidence of Barrett's esophagus. However, the mortality of EGDA + Fe is significantly lower than that of EDA + Fe, and it is similar to the pathogenesis of human GERD. Therefore, it can be better used to make animal model of Barrett's esophagus.2 The expressions of ERK1/2, p-ERK1/2, and CyclinE in the normal esophageal squamous epithelium, reflux esophagitis and Barrett's esophagus have been gradually increased, which indicates that ERK signale pathway has involved in the pathogenesis of Barrett's esophagus and may promote the occurrence of Barrett's esophagus by increasing the expression of CyclinE. The activation of ERK signal transduction pathway plays an important role in the occurrence of Barrett's esophagus.