The use of manganese-enhanced magnetic resonance imaging in rat radiation-induced optic neuropathy / 中华放射医学与防护杂志

ABSTRACT

Objective To establish a rat model of radiation-induced optic neuropathy ( RION) by delivering a single radiation dose to the optic chiasm. The aim of our study was to analysis the feasibility and effectiveness of manganese-enhanced magnetic resonance imaging ( MEMRI) in RION. Methods 34 Wistar rats were randomized to the control group(4 rats), the 2-month group(5 rats),the 4-month group(4 rats) and the 6-month group(11 rats) according to the different feeding period after irradiation. MEMRI scan were performed when the respective feeding periods of all groups expired. The rats were then killed for histological studies with hematoxylin and eosin stain, Luxol Fast Blue stain, and electron microscopy analysis. Results The ratio of RION in the four groups were 0/3, 1/5, 2/4 and 11/11, respectively (χ2 =15?443, P<0?05). There was an inverse correlation between the relative optical density value in the LFB stain and the interval between irradiation and pathological examination(R= -0?643,P<0?05). The number of glial cells in the HE stain in the four groups were 194 ± 65, 234 ± 19, 124 ± 11 and 345 ± 98, respectively(R=0?590,P<0?05). When compared MEMRI scan with the corresponding histological examination, we found that there was loss of signals of optic nerve on MEMRI imaging in one of 5 rats in the 2-month group, while no significant histological difference was found between this rat and the others. Conclusions RION can be non-invasively detected and semi-quantitative analysed by MEMRI scan. Moreover, RION can be early diagnosed by MEMRI scan which is capable to show physiological change in advance of pathological change.