To investigate the protective effects of perfluorooctyl-bromide (PFOB) nanoparticles on early brain injury (EBI) following subarachnoid hemorrhage (SAH), a total of 120 rats were randomly assigned to the following groups: Sham operation group (n = 40), SAH group (n = 40), and SAH + PFOB group (n = 40). Endovascular perforation was performed to induce subarachnoid hemorrhage. Brain water content was measured 24 h after surgery. Meanwhile, morphological changes in the rat hippocampal CA1 region were examined using light and transmission electron microscopy. The rate of neuronal apoptosis in rat hippocampal CA1 region was determined using TUNEL assay. Protein and mRNA expression levels of Caspase-3, Bax, and Bcl-2 were measured using western blot and RT-PCR assays 12, 24, 48, and 72 h after surgery. Compared to the SAH group, the SAH + PFOB group had significantly lower brain water content (P<0.01), with alleviated morphological abnormalities in HE-stained neurons and significantly decreased neurons with karyopyknosis and hyperchromatism in the hippocampal CA1 region. Electron microscopy revealed reduction of neuronal apoptosis, alleviation of glial cell swelling, and mitigation of perivascular edema in the hippocampal region. Immunohistochemical analysis showed that the expression of apoptosis-related factors Caspase-3 and Bax was significantly reduced, while that of the anti-apoptotic factor Bcl-2 was significantly increased. TUNEL staining showed that neuronal apoptosis was significantly reduced in the hippocampal CA1 region (P<0.01). RT-PCR and Western-blot data indicated that expressions of Caspase-3 and Bax were both significantly reduced, while bcl-2 expression was increased significantly at 12, 24, 48, and 72 h after SAH (P<0.01). Together, our data support that PFOB nanoparticles with high oxygen content could counteract ischemia and hypoxia, block neuronal apoptotic pathways, reduce neuronal apoptosis, and therefore, achieve neuroprotective effects in EBI following SAH.
Keywords: Subarachnoid hemorrhage; apoptosis; early brain injury; neuroprotection; perfluorooctyl-bromide.