| [Objective]1. Prepare iron oxide nanoparticles by chemical method and study the vivo biodistribution the nanoparticles with the mice .2. Iron oxide nanoparticles were used as simulate to observe adverse effects of atmosphere particle matter on hypertension SHR rats3. In MR observe the T1 and T2 relaxation time change of liver and spleen after inject iron oxide nanoparticles into monkey via vein and further evaluate that iron oxide nanoparticles preparaed in our laboratory could be MR contrast agent.[Methods]1. Iron oxide nanoparticles were prepared by coprecipitate and the particle diameter and appearance were measured with high performance particles sizer , scanning probe microscopy and scanning electron microscope. The ferric concentration of iron oxide nanoparticles were determined by 1,10-Phenanthroline monohydrate with spectrophotometric method.2. Iron oxide nanoparticles and chloride ferric labeled with 59Fe were injected into mice via tail vein to compare the biodistribution of iron oxide nanoparticles with that of chloride ferric. The radioactivities in blood , liver, spleen and other organs were measured at 2min,10min ,30min ,1h, 2h, 8h,24h ,5d,15d,30d after injection.3. 59Fe-iron oxide nanoparticles were infused into mice via intragastric administration and the the radioactivities in blood , liver, spleen and other organs were measured at 30min ,1h, 2h,4h, 8h,24h ,48h,5d,15d,30d after injection.4. 59Fe-iron oxide nanoparticles were administrated into hypertension SHR rats via trachea. To observe the influnce of iron oxide nanoparticles on hypertension SHR rats,the the radioactivity in blood , liver, spleen and other organs were measured at 10min ,30min ,1h, 12h ,24h, 48h after injection. 5. MR imaging was performed to observe the T1 and T2 relaxation time change of liver and spleen after injection 20mL 1 mg·mL-1 Fe into monkey via vein .[Results]1. The diameter of iron oxide nanoparticle particles were distributed uniformly,at a mean diameter about 30nm. The Fe concentration was (7.6±1.55)mg·mL-1.2. After injection 59Fe-iron oxide nanoparticles via tail vein, main uptake of 59Fe-iron oxide nanoparticle was in liver and spleen. The percent injected dose per gram organ (%ID/g) were (55.59±14.27)%ID/g and (22.09±8.84)%ID/g at 8 h and 2 h after injection, respectively. 59Fe-iron oxide nanoparticle in blood was initially rapidly decreased and then gradually increased after five days ,at 30 days the was (13.22±1.79)%ID/g. Compared with chloride ferric, the iron oxide nanoparticle can prolong circulation time in vivo. At 5 days, the %ID/g of liver were (25.51±6.05) in iron oxide group, but only (7.19±3.52)%ID/g in chloride ferric group. The %ID/g of bone in iron oxide group was (12.35±9.31)%ID/g at 5 days, and those of other organs were at low level.3. In intragastric administration group, iron oxide nanoparticles were firstly distributed in stomach and intestine, the uptakes of stomach and intestine were (8.73±5.77) %ID/g and (3.03±3.05) %ID/g at 30 min. The peaks reached in blood and liver with the values of (1.08±0.28)%ID/g and (1.19±1.26)%ID/g at 2h respectively after administration, then decreased gradually. After 4h, there were paeks in spleen and bone with the values of (2.69±2.03) %ID/g and (4.80±2.28) %ID/g.Then the %ID/g of all organs decreased to a low level.But blood and bone were increased at 15 days and 30 days,the values were (5.51±8.50) %ID/g and (1.73±3.81) %ID/g, respectively.4. 59Fe-iron oxide nanoparticles were mainly distributed in lung in rats via in tragastric administration, then in liver and spleen. Nanoparticles of hypertension group more difficultly passed from lung to blood and excreted slowly than normal group.5. T1 and T2 relaxation time of MRI in normal liver and spleen of monkey can be shorted through iron oxide nanoparticle administration. The results showed that iron oxide nanoparticle preparaed in our laboratory could be a promising contrast agent for liver and spleen. After administration,the monkeys were as usual and didn't show any adverse reactions. [Conclusion]1. The iron oxide nanoparticles we synthesized were in stable physical properties and distributed uniformally.2. Nanoparticles mainly distributed in liver and spleen. Compared with chloride ferric, it could prolong circulation time in vivo.3. Through MRI, we observed it could shortening T1 and T2 relaxation time in normal liver and spleen of monkey and it would be a promising contrast media applicated in hepatic and splenic MR.4. Via intragastric administration, nanoparticle mainly distributed in spleen and bone and take part in synthesis of red-cell. Through improvement , iron oxide nanoparticel would be a promising hematic for iron deficiency anemia.5. Nanoparticles were more harmful to hypertension group because via pulmonary perfusion,the particles could difficultly transport from lung to blood and be hardly excreted through feces, so the hypertension patients may be the sensitive group.
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