Correlation Studies Between MTHFR C677T Gene Polymorphism And Pulmonary Embolism

ObjectivesStudy of using modified phenol-chloroform methods of DNA extraction from formalin fixed tissue,compared to the pros and cons of extraction quality of DNA from heart, liver, lung and brain of four kinds of tissue, so as to extract DNA from formalin-fixed by pulmonary embolism leading to death of the deceased organs and amplify the target fragment, in order to probe the relationship between the mutation gene C667T of methylenetetrahydrofolate reductase(MTHFR) and pulmonary embolism to provide reference for forensic pathology tests in death caused by pulmonary embolism.Methods1. Comparison of DNA extraction from different tissues fixed in formalin: Selected each of formalin fixed specimens of tissue in14cases with proteinase k digestion and were extracted of their DNA by the methods of improved phenol-chloroform method. The quality of obtained DNA was analyzed to judge by UV spectrophotometer、PCR amplification and agarose gel electrophoresis.2. Correlation studies between MTHFR C677T gene polymorphism and pulmonary embolism:Selected formalin-fixed pulmonary embolism lead to the death of the deceased’s liver in14cases (PE group), DNA was extracted by using the modified phenol-chloroform extraction method, as well as the normal bloodstains60cases (control group), extracted DNA using by Chelex-100extraction method. The two groups were amplified for the same target fragment by PCR, observed the difference of the target bands after agarose gel electrophoresis, and count the number of the genotype and allele frequency. Results1. Comparison of DNA extraction from different tissues fixed in formalin: The ratio of OD260/OD280of extracted DNA from the four kinds of tissue were1.842±0.380、1.861±0.076、1.387±0.113、1.428±0.087。The yields(μg) of DNA in every100mg tissue were0.944±0.530、1.096±0.544、0.348±0.273、0.601±0.238. The agarose gel electrophoresis analysis after PCR amplification displayed that the bands of cardiac muscle and liver tissue were better than lung and brain tissue.2. Correlation studies between MTHFR C677T gene polymorphism and pulmonary embolism:MTHFR C677T genotype-CC, CT and TT in the distribution frequency of PE group were:35.7%,57.2%and7.1%, respectively; in the control group were:50%,43.3%and6.7%. PE group CT, TT genotype frequency and T allele frequency was obviously higher than that in the control group, but the difference of genotype and allele distribution between two groups was not statistically significant (P>0.05). Compared with CC genotype, the risk assessment of CT, TT genotypes also showed no statistical significance.Conclusion1. Comparison of DNA extraction from different tissues fixed in formalin: The obtained quality of DNA to be more reliable by using improved phenol-chloroform extraction methods from the formalin fixed cardiac muscle and liver tissue, and can be used for follow-up studies.2. Correlation studies between MTHFR C677T gene polymorphism and pulmonary embolism:Genotype of MTHFR C677T polymorphism may be not associated with existing samples of pulmonary embolism.