A multifunctional contrast dye for morphological research

Abstract

RIO proved to be a multifunctional contrast dye, which could be applied as an imaging biomarker for tissue vascularity or blood perfusion, for visualization of organ anatomy and for ex vivo validation of in vivo animal experiments.

An Imaging and Histological Study on Intrahepatic Microvascular Passage of Contrast Materials in Rat Liver

“…Human pathology has demonstrated alterations of the PVP under normal and diseased conditions [ 22 ], but it is impossible to expose the entry and exit of blood through this system. By staining red color to the liposoluble LPD [ 15 ] and using the BSS as a hydrosoluble alternative [ 14 ], this study has provided colorful histomorphologic evidence to support the previous “grayscale” findings [ 8 ] that indeed the PVP transported the arterially injected LPD and BSS into the PV branches. Although the PVP could be observed by the operator of the intravital microscope, the published black-white pictures failed to depict local structures, with labels or sketches needed to aid imagination [ 8 , 23 ].…”

“…Technically, experimental studies on LPD proved challenging, because oily LPD becomes void in both paraffin and conventional lipid staining methods due to dissolution and/or washout of LPD by the applied organic solvents. By the prior coloration with Oil-red-O [ 15 ] and modified staining method, for the first time to our knowledge, we could microscopically identify the distribution of LPD in various locations of intrahepatic microcirculation. Furthermore, our experiment showed that both RIO and BSS took the same route in hepatic vasculature, making it possible to replace LPD by BSS to conduct standard morphology and quantification.…”

“…This study entailed the following methodological improvements. First, the applied bifunctional RIO contrast dye enabled high-quality images in DR, gross histology, and microscopy, allowing visualization and quantification of the liver vasculature [ 15 , 16 ]. Secondly, the RIO/BSS were infused through catheterization of the carotid artery and under DR monitoring in order to get the whole-body angiography [ 14 ].…”

“…A custom-made multifunctional contrast dye, namely, red iodized oil (RIO), was formulated by solubilizing 500 mg Oil-red-O pigment (Sigma-Aldrich) in 100 mL of Lipiodol (LPD) ultra-fluid (Guerbet, France) [ 15 ]. Being otherwise almost colorless as seen with LPD, RIO becomes a bright red dye for staining tissue structures especially blood vessels, making them discernable both grossly in organs/tissues and microscopically on frozen sections [ 15 , 16 ]. Meanwhile, RIO functions as a contrast agent for both X-ray based imaging modalities and magnetic resonance imaging (MRI) without significantly altering physiochemical properties of LPD [ 15 ].…”