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Biological Effects and MR Signal Detection of Different Materials Coated SPIOs on Macrophages

Author: TanYanBin
Tutor: ZhangMinMing
School: Zhejiang University
Course: Medical Imaging and Nuclear Medicine
Keywords: Superparamagnetic iron oxide Cell markers Cell activity Citric acid Dextran Magnetic resonance imaging Cytoskeletal Cell migration
CLC: R363
Type: Master's thesis
Year: 2010
Downloads: 84
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Abstract

Background research purposes inflammatory response plays an important role in the development and transfer process in the body part of cardiovascular disease and nervous system diseases, including T cells, B cells, and most of the macrophage cells, including white blood cells can migrate to lesion and gathered. Usually evaluate the inflammatory response of these diseases requires histological examination, but this check is only observed lesion inflammation still can not dynamically observed inflammatory cell migration to the lesion, and traumatic. If real-time is not invasive observation of the inflammatory response of these diseases, the treatment and prognosis of the disease is important. In recent years, the rapid development of molecular imaging makes it possible. Superparamagnetic iron oxide (SPIO) mark on macrophages, thus tracing the migration and distribution in the body, capable of dynamic non-invasive evaluation of the body's inflammatory response. When SPIO injected into the body through a vein, with the blood circulation in the human body. Mainly through the liver in vivo SPIO cleaned, the reticuloendothelial system and the phagocytic cells in the blood intake SPIO after ingestion by phagocytic cells in the blood, does not again be discharged from the cells, so that the phagocytic cells are marked, and the mark phagocytic cells can migrate to the site of inflammation where and gathered, magnetic resonance scan, can cause inflammation site where T ₂ relaxation time for the signal to reduce the magnetic resonance image. In general, SPIO mainly by the kernel and package material in two parts, and the inner diameter of the nanoparticles from a dozen to several hundred nanometers. Kernel by Fe ₃ O ₄ and / or γFe ₂ O ₃ which package many types of materials, The packet is the presence of the material to improve the stability and biocompatibility of SPIO, and the packet is the presence of the material, but also can facilitate further modification of the SPIO SPIO, thereby enabling a targeting or specificity. So far, many scholars use the SPIO to mark is activated or not activated macrophages, and inflammatory reaction in vivo was evaluated. These studies are fully SPIO-labeled macrophage inflammatory response in vivo evaluation has a great advantage. Nevertheless, as the SPIO package material and an inner diameter, there are great differences the SPIO package utilized in these studies is the material and the inner diameter size are not the same, so the comparability of the results obtained is poor. If you can define an optimal SPIO used to mark the macrophage, not only a high labeling efficiency, and high biocompatibility, for further research has important significance. But little research. In the present study, we compared the in vitro citric acid and dextran coated SPIO different labeling efficiency of the mouse macrophages and marked changes in cell function, and magnetic resonance imaging effect was evaluated. Which the SPIO is more suitable for the tag macrophages provide an experimental basis for further biological applications to try to understand. Materials and methods in accordance with the co-precipitation method synthetic citric acid and dextran coated SPIO. Separation of about 6-week-old female ICR mouse peritoneal macrophages. After the macrophages and the concentration of 0.25mg/ml SPIO incubated for 1 hour together by Prussian blue staining efficiency was observed on the two materials coated SPIO labeled macrophages. Concentrations were 0.1,0.25,0.5,0.75,1.0 mg / ml of SPIO after the mark is carried out on macrophages, using Calcein-AM method evaluate the activity of macrophages in the different concentrations of SPIO labeled. The macrophage and concentration of 0.5mg/ml of SPIO co-incubated for 1 hour, to observe changes in the migration ability of cells through the cell scratch test, pixel analysis to evaluate the changes in the capacity of the cell migration with the imageJ. Macrophages and concentration of 0.5mg/ml the SPIO co-incubated for 1 hour, labeled cells proinflammatory cytokines IL6 24 hours was measured by enzyme-linked notation secretion. SPIO with macrophages of four concentrations of the 0.1,0.25,0.5,0.75,1.0 mg / ml after incubated for 1 hour together with 0.5% agar gel is fixed to a 96-well plate, in the PHILIPS 3.0T magnetic resonance whole body scanner scan, to evaluate the change of the relaxation time in the concentration of different incubation. SPIO incubation concentration cell relaxation time and cell activity by two-way ANOVA, and multiple comparisons. SPIO cell migration ability and the amount of secretion of proinflammatory cytokines by student t test. Results using the classical coprecipitation method SPIO brownish black gelatinous liquid, citric acid-coated SPIO the hydrated inner diameter of about 100 nm, citric acid coated SPIO the hydrated inner diameter of about 150 nm nano particle size distribution better. Stored at 4 ℃ SPIO stability. Prussian blue staining showed not co-incubated with SPIO macrophages was dyed a homogeneous red, blue iron particles with SPIO co-incubated for 1 hour after the macrophage cytoplasm citrate coated SPIO than dextran sugar coated SPIO easier to enter into the cell, i.e. a high labeling efficiency. Measuring the activity of the cells results show cell activity decreases with the increase in the concentration of SPIO incubated When SPIO incubated concentration 0.25mg/ml from two materials coated SPIO there are toxic effects on the cell. In addition, two packet by comparing the same kinds of incubation concentration SPIO cell active material found two packages of materials SPIO macrophages in the same concentration was not statistically significant. Determination of cell migration results show that both packages SPIO-labeled cell migration in the material is no significant change in this SPIO does not affect cell migration. Promoting cytokines measuring results show that citric acid coated SPIO labeled macrophages promote increased secretion of inflammatory factors and dextran coated SPIO labeled cells no increase. Citrate coated SPIO labeled macrophages displayed in the results of MRI scans can obviously cause T ₂ decrease in the relaxation time, and the dextran-coated SPIO at the highest incubation concentration will cause T ₂ reduction of the relaxation time. The conclusions in vitro tests confirmed the citrate coated SPIO more suitable marker macrophages. The citrate coated SPIO phase dextran coated SPIO macrophage marker higher efficiency, and more likely to cause changes in the magnetic resonance signals. Impact on cell function, citric acid coated SPIO labeled macrophage cell activity and the change of cell migration ability of dextran coated SPIO labeled macrophages are the same but the amount of secretion of proinflammatory cytokines will increase .

Biological Effects and MR Signal Detection of Different Materials Coated SPIOs on Macrophages

Abstract

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