Application Of Functional Magnetic Nanoparticles In The Study Of Essentional Hypertension Susceptibility

The study of genetic effect of complex diseases benefits to the exploitation of effective medicines. Essential hypertension (EH) is a common kind cardiovascular disease, with growing up morbidity. EH is a result of multiple reactions of genetics and environment. The symptom of family EH certified the existence of genetic factor in a further step. The susceptibility between angiotensinogen gene of rennin-angitensin system gene group and EH has become a hot topic.In order to show the susceptibility of AGT and EH, the relationship between EH and two loci M235T and A-6G located in angiotensinogen gene was studied.In this work, superparamagneticγ-Fe₂O₃ magnetic nanoparticles with average size of 30 nm were prepared, with magnetic saturation of 48.4 emu/g. The particles functionalized with streptavidin were proved to be bio-active and could be used in biology test. Utilizing the super specific bonding effect of biotin-streptavidin system, streptavidin modifiedγ-Fe₂O₃ nanoparticles were used in SNP detection. 243 EH samples and 247 healthy samples in Hunan area were collected. The SNP of two loci, M235T and A-6G located in angiotensinogen gene, were detected. PCR products were modified on the streptavidin-γ-Fe₂O₃ nanoparticles, then hybridized with two probes labeled with two fluorescence colors: Cy5 and Cy3. The hybridization results were scanned with a GenePix 4100 scanner. When the sample is homozygous, the ratio of Cy3 to Cy5 is higher than 3. When the sample is heterozygous, the ratio is between 0.64 and 1.7. This SNP typying method had been proved to work well.After statistic analysis using SPSS 13.0 software, the difference of gene type CC, CT, TT ratio on M235T locus between the sick group of EH and the healthy group was found significant (χ2=5.532,P=0.063). And so was the difference between the allele gene C, T (χ2=5.745,P=0.017). The morbidity of individuals with mutation type TT was found greater than the others. There may be some correlation of the mutation type TT with essential hypertension in people of Hunan area. The difference of gene type AA, AG, GG ratio on A-6G site between the sick group of the EH and healthy group was found not significant (χ2=1.701,P=0.427). And neither was the difference between the allele gene C, T (χ2=1.436,P=0.231). The SNP of A-6G locus may not be a dangerous factor of essential hypertension in people of Hunan area.