In vivo Magnetic Resonance Imaging of Tuberculous Meningitis Rat Model using Near-Infrared Long-persistent Luminescent Nanomaterials

This research was aimed to explore the adoption value of near-infrared (NIR) long-persistent luminescent nanomaterials for in vivomagnetic resonance imaging (MRI) of tuberculous meningitis in rat model. Firstly, NIR long-persistent luminescent nanomaterials were synthesized using the sol-gel methodology. The materials were thoroughly evaluated using X-ray diffraction, characterization techniques, fluorescence spectroscopy, and property analysis, with investigations into the effects of different thermal treatment temperatures.A tuberculous meningitis rat model was established in five rats (experimental group), while other five rats were injected with saline (control group). The successful establishment of the model was confirmed through hematoxylin-eosin (HE) staining. The remaining rats from each group were selected for further analysis (ZnGa2O4:Cr3+NIR group and saline group). The prepared ZnGa2O4:Cr3+NIR solution was injected into ZnGa2O4:Cr3+NIR group, while saline was injected into saline group. The effects of these injections on NIR imaging and their impact on MRI were subsequently analyzed.The synthesized ZnGa2O4:Cr3+ nanomaterials exhibited uniform particle sizes ranging from 40 to 80 nm, with a NIR emission peak at 709 nm. The afterglow decay curve demonstrated an initial rapid decay followed by stabilization, with the optimal excitation time determined to be 15 minutes. Histopathological analysis confirmed the successful establishment of rat model, with experimental group showing significantly higher inflammatory cell counts (48.3 ± 6.7 vs. 16.2 ± 1.5 cells/field, P<0.05) and histological scores (3.7 ± 0.5 vs. 0.5 ± 0.3, P<0.05) compared to control group. After injection of nanomaterials, MRI signal intensity in experimental group was significantly enhanced, with the signal-to-noise ratio increasing from 4.5 ± 0.8 to 8.2 ± 1.2 (P<0.05) and the contrast-to-noise ratio rising from 1.9 ± 0.4 to 3.5 ± 0.6 (P<0.05). Additionally, the ventricular area in the experimental group was approximately 15% smaller than that of control group (0.38 ± 0.05 cm2vs. 0.45 ± 0.06cm2, P<0.05).In vivoMRI imaging based on NIR long-persistent luminescent nanomaterials showed a good application potential for the research of tuberculous meningitis rat model. Keywords: near-infrared long-persistent luminescent nanomaterials; tuberculous meningitis; animal model; in vivo magnetic resonance imaging