Abstract
The catalytic performance and therapeutic effect of nanoparticles varies with shape. Here, we investigated and compared the therapeutic outcomes of ceria nanospheres (Ceria NSs) and ceria nanorods (Ceria NRs) in an in vivo study of mild traumatic brain injury (mTBI). In vivo TBI was induced in a mouse model of open head injury using a stereotaxic impactor. Outcomes including cytoprotective effects, cognitive function, and cerebral edema were investigated after retro-orbital injection of 11.6 mM of ceria nanoparticles. Ceria nanoparticles significantly reduced fluoro-jade B (FJB)-positive cells and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive cells, and restored mRNA levels of superoxide dismutase 1 (SOD1) and SOD2. They also decreased the cyclooxygenase-2 (COX-2) expression compared with the untreated control group. Comparing the two nanomaterials, Ceria NRs showed less stable and high-energy (100) and (110) planes, which increased the number of active sites. The Ce3+/Ce4+ molar ratio of Ceria NRs (0.40) was greater than that of Ceria NSs (0.27). Ceria NRs (0.059 ± 0.021) appeared to exhibit better anti-inflammatory effect than Ceria NSs (0.133 ± 0.024), but the effect was statistically insignificant (p = 0.190). Ceria nanoparticles also improved cognitive impairment following mTBI compared with the control group, but the effect did not differ significantly according to the nanoshape. However, Ceria NRs (70.1 ± 0.5%) significantly decreased brain water content compared with Ceria NSs (73.7 ± 0.4%; p = 0.0015), indicating a more effective reduction in brain edema (p = 0.0015). Compared with Ceria NSs, the Ceria NRs are more effective in alleviating cerebral edema following in vivo mTBI.
Highlights
Is attributed to their high catalytic activities owing to rapid transformation of the oxidative states of Ce3+ and Ce4+[13]
Recent studies reported that ceria nanoparticles with a spherical shape decreased neuronal cell death and calcium dysregulation by preserving the antioxidant system in the mild TBI (mTBI) model[7]
Scanning electron microscope (SEM) and transmission electron microscope (TEM) images (Fig. 1A,B) of the obtained products revealed that Ceria nanorods (Ceria NRs) had a rod-like morphology measuring 130.1 ± 42.1 in length and 9.4 ± 2.1 in diameter (Fig. S1 A and B), while Ceria nanospheres (Ceria NSs) (Fig. 1E) were uniform and spherical with a mean particle size of approximately 3.5 ± 0.5 nm (Fig. S1C)
Summary
Is attributed to their high catalytic activities owing to rapid transformation of the oxidative states of Ce3+ and Ce4+ (so called oxygen storage capacity)[13]. Ceria nanoparticles exhibit oxygen vacancies in the lattice structure due to the loss of electrons or oxygen atoms, leading to a switch between C eO2 and C eO2-x during redox processes[14]. Controlling the morphology is critical to the catalytic performance of ceria nanoparticles, since the selective exposure of reactive crystal planes on the surface can enrich the catalytic s ites[15,16]. Recent studies reported that ceria nanoparticles with a spherical shape decreased neuronal cell death and calcium dysregulation by preserving the antioxidant system in the mTBI model[7]. No comparison with other nanodrugs was made, and the studies merely demonstrated better therapeutic efficacy of ceria nanoparticle in injured mice compared with untreated animals[7]. We compared the possible differences in therapeutic effects of ceria nanoparticles (nanospheres vs nanorods) in a mouse model of mTBI
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