| Objective:Tongue cancer is the most common malignant tumor of oral and maxillofacial region,of which more than 80%are squamous cell carcinoma.It has high degree malignancy and strong invasion,serious threat to human health.In the past 30 years,scholars attempt to improve the cure rate of tongue squamous cell carcinoma and have done a lot of research,but its five-year survival rate is still less than 50%.As the deep development of molecular oncology,people aware that cancer occurs due to the abnormal molecular signals.These molecular signals regulate cell growth and death.So when they are abnormal,cell grow will lose normal regulation.Scholars think that drugs which target to these lesions is expected to become efficient and low toxicity new anti-cancer drugs.The study found that E-cadherin,which is a epithelial adhesion molecule,plays a significant role in the occurrence and development of tongue squamous cell carcinoma,and E-cadherin downregulation closely associated with tissue differentiation,invasion,metastasis and prognosis of tongue squamous cell carcinoma.E-cadherin can inhibit tumor cells and host cells to produce matrix metalloproteinases,thereby prevent basement membrane and various proteins constituents from degradation,these proteins constituents are in the tumor cells surrounding matrix.And ultimately they can inhibit tumor cell to breakthrough matrix and basement membrane barriers.E-cadherin expression loss or decrease can promote invasion and metastasis of tumor cells.But the causes of E-cadherin downregulation and it how impact occurrence and development of tongue squamous cell carcinoma are unclear.The purpose of this experiment are through establishing animal model of tongue squamous cell carcinoma and collecting tissue samples in various stages of tongue carcinogenesis,to measure the relative expression level of E-cadherin mRNA of specimens,to clear whether E-cadherin mRNA changes or not in the process of tongue mucosa carcinogenesis and the specific phase of changes occurring,to provide experimental evidence for the development of the new anti-tongue squamous cell carcinoma drugs.Methods:4NQO Drinking Water Act was used and squamous cell carcinoma of rats tongue were induced successfully,and epithelial hyperplasia,mild dysplasia,moderate dysplasia,severe dysplasia and squamous cell carcinoma specimens of the rat tongue mucosa during tongue Carcinogenesis were collected.The collected tissue samples were divided into two parts.One part of samples were fixed with paraformaldehyde which mass fraction is 4%,dehydrated graded ethanol,embedded in paraffin,sliced and HE stained,and then two experienced pathologists independently read sheet and pathological grading was made.The other part of the tissues were quick-frozen in liquid nitrogen,then were transferred to-80 ? refrigerator spare.To obtain CT value of E-cad gene and the reference gene P-actin real-time quantitative PCR method was used,and then we obtained the relative expression of E-cad mRNA by calculating the 2-??CT value of E-cad gene in diseased tissues and normal tissues.The changes of E-cad mRNA and the specific stages of changes in the process of tongue carcinogenesis were observed.Results:4NQO Drinking Water Act successfully induced rat tongue squamous cell carcinoma.And we detected that tongue mucosa of rats began to appear white spots or patches after eight weeks of drinking 4NQO solution.With the extension of treatment time,papilloma lesions or ulcers appeared in the same area.When the end of the experiment we have collected 82 specimens of tongue mucosa.These specimens included 21 tissues of normal epithelium,21 tissues of epithelial hyperplasia,14 tissues of mild dysplasia,8 tissues of moderate dysplasia,2 tissues of severe dysplasia and 16 tissues of Well-differentiated squamous cell carcinoma.And the relative expression levels of E-cadherin mRNA in 57 tissue samples were detected by real-time quantitative PCR method.In the 57 tissue samples of tongue,there are 10 normal epithelium specimens,15 epithelial hyperplasia specimens,11 mild dysplasia specimens,3 moderate dysplasia specimens,2 severe dysplasia specimens and 16 squamous cell carcinoma specimens.The average ?CT value of normal tongue mucosa group is 0.53.The averageACT value of epithelial hyperplasia group is 1.05.The average ACT value of mild dysplasia group is 3.53.The average ?CT value of moderate and severe dysplasia group is 3.81.The average?CT value of squamous cell carcinoma group is 3.50.In addition to epithelial hyperplasia group,the differences between the rest of the group and normal tongue mucosa group were statistically significant(P<0.05);and the differences between epithelial hyperplasia group and epithelial mild,moderate,severe dysplasia also were statistically significant(P<0.05).Take 2'??CT of normal tongue mucosa group is 1,2-??CT of the epithelial hyperplasia group,mild dysplasia group,moderate and severe dysplasia dysplasia group,squamous cell carcinoma group respectively is 0.70,0.12,0.10,0.12.That is,expression of E-cad mRNA in epithelial hyperplasia tissues is0.70 times the normal epithelial tissues.Expression of E-cad mRNA in mild epithelial dysplasia tissues is0.12 times the normal epithelial tissues.Expression of E-cad mRNA moderate and severe epithelial dysplasia tissues is0.10 times the normal epithelial tissues.Expression of E-cad mRNA in squamous cell carcinoma tissues is0.12 times the normal epithelial tissues.Conclusion:1.4NQO Drinking Water Act can induce rat tongue squamous cell carcinoma,and these squamous cell carcinoma mainly are well-differentiated squamous cell carcinoma.2.The time from mild epithelial dysplasia to squamous cell carcinoma during the course of well-differentiated squamous cell carcinoma of SD rats is very short.3.E-cadherin mRNA changes during SD rat tongue mucosa carcinogenesis,and with the increase of pathological grade,E-cadherin mRNA expression shows a decreasing trend.4.The change of E-cadherin mRNA expression is an early event in SD rat tongue mucosa carcinogenesis. |
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