Study On The Expression Of Telomerase Activity And Its Related Genes In Marrow Hemopoietic Stem Cells Of Children With Aplastic Anemia

Aplastic Anemia(AA) is a hematological systemic disease caused by different kinds of reasons, included physical,chemical, biological and other indefinited factors,in which the bone marrow hematopoietic function failure.It manifests bone marrow hematopoietic stem cells and bone marrow microenvironment severely damaged and leads to pancytopenia eventually. The disease has long treatment duration, low curative rate, and high mortality, so it brings great physically and mentally harm to the patients. However, the pathogenesis have not been comprehensively understood up to now.Researchers believe that the major mechanism of aplastic anemia has a relation with the abnormalities of immunocyte and its activation signals. However some studies show that the Genetic Susceptibility produces a marked effect in aplastic anemia, especially the mutations and changes of some genes are noticed by more and more researchers. The hematologic researchers have pay close attention and more intreasts on the expression of telomerase activity and its related genes in the pathogenesis of aplastic anemia.Telomeres are specialized nucleoprotein structures formed caps at the terminal ends of chromosomes in eucaryotic cells. The main function of telomeres is to cap the chromosome ends in order to protect chromosome ends from end to end fusion, recombination,and degradation.But the length of telomere will be have a shortening related with aging,at this time a special enzyme called telomerase is often required to synthesize telomere DNA for compensating for the shortening. Telomerase consists of two essential components:telomerase RNA component (TERC) and telomerase reverse transcriptase (TERT), and can provide functional RNA which serves as a template to finish telomere sequence synthesis. Telomerase play a important role at the mataining of telomere length and stability.When the length of telomere shortened at some extent,the expression of telomerase activity will become consequential.Some studies show that the length of telomere in granulocytes of patients with aplastic anemia.However the hematopoietic stem cells of children have a high potentiality of multiplication,and the telomere shortening is not obviously. So how about of the expression of telomerase activity and its related genes in the hematopoietic stem cells of children with aplastic anemia,and weather it will be affected with the changes of telomere length.For the above resons,we are going to carry out this study.ObjectiveTo study the explore the expression of hTERC, hTERT and telomerase acticity in marrow hemopoietic stem cells of children with Aplastic Anemia,and explore the relationships between them.With clinical datas,to seek some new guidances and therapeutic methods for the patients with aplastic anemia.Materials and MethodsFifty-two children with chronic AA,13children with acute AA and21normal controls from the Third Affiliated Hospital of Zhengzhou University and the First Affiliated Hospital of Zhengzhou University were enrollded. All of them were without any treatment.Telomerase acticities of three groups were detected by Telomeric Repeat Amplification Protocol (TRAP) with silver staining,and the expression of mRNA of hTERT and hTERC were detected by real-time Q-PCR. The results were analyzed by SPSS17.0statistic software, quantitate dates were showed as (x±s), comparisons between groups were analyzed with one-factor analysis of variance, comparisons in one group use the way of LSD, association analysis use linear correlation,it will have statistical significance when P≤0.05.Results1. Expression level of telomerase activity:the group with CAA is41.35±10.28, the group with SAA is31.86±8.54, which are significantly higher than the control group (23.50±9.13), and approximately to the control group (5.91±1.51),and the CAA group shows to be significantly higher than SAAgroup.2. Expression level of hTERT mRNA:CAA group(9.86±1.10)and SAA group (5.12±0.89),) had significantly higher expressions of hTERT mRNA than control group (1.17±0.73)(P<0.01).3. Expression level of hTERC mRNA:there are no significant differences among CAA group (1.23±0.50),SAA group (1.13±0.45),and control group (1.18±0.64)(P=0.812).4. There was a significant correlation between the expression of hTERT mRNA and telomerase acticity (r=0.660,P<0.01)Conclusion1. In marrow hemopoietic stem cells of children with aplastic anemia, both telomerase acticity and the expression of hTERT mRNA are higher in children with AA than that in normal ones, there is a significantly positive correlation between them.2. The expression of telomerase acticity may be involved in pathophysiology and development of AA, and hTERT plays a crucial role in expression of telomerase acticity.