Study On The Telomere DNA Length Of The Peripheral Blood Leukocyte From Persons Living In Bama County, Guangxi

OBJECTIVE: To discuss if the telomere DNA length of the peripheral blood leukocyte from persons living in Bama County is associated with the age, analyze the speed of the telomere DNA length shortening with aging between the case group and the control group, and explore the possible relationship between the longevity and telomere.METHODS: 1. Telomere length detecting method was established by Southern blotting with digoxigenin-labeled hybridization probe. 2. Forty-nine peripheral blood samples of healthy individuals were selected as the case group in the longevity cases from Bama County, and another fifty-one peripheral blood samples of healthy individuals were selected as the control group in the healthy populations undergone health examination from the First Affiliated Hospital of Guangxi medical University. Both the case group and the control group were divided into four groups according to the age, viz, youthful age group(<35 years old), middle age group(≥35 years old, <64 years old), old age group(≥64 years old,<85 years old) and longevity group(≥85 years old). Mean telomere length (telomere restriction fragment, TRF) was examined by Southern blotting with digoxigenin-labeled hybridization probe. 3. SPSS13.0 statistics software was used to analyze data from experiment.RESULTS: 1. Telomere length detecting method by Southern blotting was optimized. And for per sample, 1.5μg of purified genomic DNA diluted with nuclease-free water to a final volume of 17μl and the reaction mixture incubated for 2 h at 37℃were considered optimal. Telomere length of control-DNA low and control-DNA high sample was 3.9Kb, 10.2Kb respectively. 2. Correlation analysis and regression analysis were performed on the average length of TRF and age. In the case group and the control group, the correlation coefficients were -0.944 and -0.942 respectively, and the regression equations were Y=11.888-0.044Xand Y=11.141-0.045X (X: age, Y:TRF) respectively. Two regression coefficients were not marked different with each other (t = 0.32, P >0.05). 3. Covariance analysis was used to analyze TRF. The TRF from the case group was longer than from the control group (P <0.05). 4. The values of mean length of TRF from different age groups were different in both the case group and the control group by using ANOVA, and the value of mean length of TRF from older group was smaller (P <0.05). 5. The statistical discrepancy of TRF from age groups between the case group and the control group were determined by using Student's t test. The values of TRF from two youthful age groups were no distinct difference (P >0.05). The values of TRF from middle age group, old age group and longevity group in the case group were all larger than in the control group (P <0.05). 6. The values of TRF from between the sexes were not different in both the case group and the control group (P >0.05). CONCLUSIONS: 1. Negative correlation is shown between telomere shortening and age both in individuals from longevity family living in Bama, Guangxi and in ordinary individuals. However, the rates of telomere length decreasing with aging in two groups are not distinctly different. 2. The mean length of TRF in individuals from longevity family living in Bama, Guangxi is longer than in ordinary individuals. It suggests that telomere length was associated with longevity phenomenon in Bama. 3. No marked difference was found in the values of TRF between the sexes both in individuals from longevity family living in Bama, Guangxi and in ordinary individuals.