The Variances Of Telomere Length In The Gastric Carcinoma,Adjacent Tumor Tissue And Normal Gastric Mucosa

Telomeres are specialized structures that cap the ends of eukaryotic chromosomes and consist of tandem repeats that are associated with an array of proteins, and in human the sequence is 5 ' - ( CCCTAA) 3-3 ' . The telomere can stabilize chromosome ends, maintain hereditary information, protect chromosome from recombination and exonuclease degradation. Research on telomere length indicate telomere sequence shorten gradually with cell division. Critical short telomeres after certain times of cell division will result in chromosomal instability, and cell growth arrest and eventually die. So the shortening of telomere can act as "mitotic clock".Telomere determines cellular life span and is closely related with cellular senescence and carcinogenesis . So more and more attention has been paid to telomere with the development of the tumor molecular biology. Research data indicate that comparing with the corresponding normal tissues, the telomere lengthes of most malignant tumor tissues shorten to a critical length. The relationships of teiomere length and clinicopathological parameters of malignant tumors haven't been revealed clearly. In this study, the alterations of telomere length in gastric carcinoma were examined and the correlation of telomerelength with some clinicopathological parameters in gastric carcinoma was analysed.Methods1. 32 samples, including tumor tissues, adjacent tumor tissues and normal gastric mucosa were collected. Tissue DNA was extracted by normal phenol/chloroform. The concentration and purity of DNA were determined by spectrophotometry.2. DNA samples were treated with Hinf I .3. Oligonucleotide probe 5 ' - ( CCCTAA) 3-3 ' was labeled with random-primed method. Then the sensitivity and the most suitable concentration of the probe were detected by dot-blot hybridization.4. The DNA fragments were separated by electrophoresis through 0.6% Agarose gel together with the molecular-weight marker A. -Hind III digest DNA. Then the DNA was transferred to nylon membranes by Southern blotting. Prehybridization and hybridization were performed at 42C in self-sealed bags.5. After immunological detection, the nitrocellulose membranes were analysed with densitometry scan. The terminal restriction fragments length was calculated according to the peak migration and was regarded as mean telomere length.6. Statistical analysis: The SPSS statistical package program 10.0 wasused for all analyses. Average ?Standard deviation ( x+s ) represented the mean telomere length. Associations between the variables were tested by x2 test , t test , K-W test and linear regression analysis. P<0.05 were deemed significant. P<0.01 were deemed highly significant.Results1. The digestion of genomic DNA by Hinf I was completed. Itshowed a DNA "smear" on the Agarose gel.2. The sensitivity and specificity of the probe qualified. And the most suitable probe concentration in the hybridization was 25 ng ml"1.3. The mean telomere length of normal gastric mucosa shortened with ageing. We analysed this tendency by using linear regression, and had got statistic significance (P<0.05).4. The mean telomere lengthes in gastric carcinoma adjacent tumor tissues and corresponding normal gastric mucosa tissues were respectively 5.088+1.712kb 5.969+1.659kb and 6.728+ 1.707kb The differences between both of them was marked(P<0.05).While 3 cases showed non-shortened telomeres in tumor tissues comparing with the associated normal tissues.5. The mean telomere length of gastric carcinoma had no relations with clinicopathological parameters.Conclusions1. There was a negative correlation between the mean telomere length and age in normal gastric mucosa.2. The mean telomere length in gastric carcinoma was significantly shorter than those in adjacent tumor tissues and corresponding normal gastric mucosa tissues. Furthermore, The mean telomere...