The Neuroprotection of Lysosomotropic Agents in Experimental Subarachnoid Hemorrhage Probably Involving the Apoptosis Pathway Triggering by Cathepsins via Chelating Intralysosomal Iron

Abstract

α-Lipoic acid-plus (LAP), an amine derivative of α-lipoic acid (LA), could protect cells against oxidant challenges via chelating intralysosomal iron. However, the application of LAP in experimental subarachnoid hemorrhage (SAH) is still not well known. This study was designed to evaluate the potential neuroprotection of LAP on the early brain injury (EBI) and the underlying mechanisms in a rat model of SAH. The SAH models were induced in Sprague-Dawley rats. LA and LAP were oral administration and lasted for 72 h once a day. The brain tissue samples were obtained for assay at 72 h after SAH. In experiment 1, we found that lysosome amounts in neurons decreased significantly in SAH group, and LAP (100 mg/kg) could stabilize lysosomal membrane markedly based on lysosomal-associated membrane protein-1 (LAMP-1) expression in neurons by immunofluorescence. Hence, the LAP dosages of 100 and 150 mg/kg were applied in experiment 2. Firstly, Western blot analysis showed that the protein levels of cathepsin B/D, caspase-3, Bax, ferritin, and heme-oxygenase-1 (HO-1) markedly increased after SAH, which were further confirmed by double immunofluorescence staining and reversed by LA and LAP treatments. In addition, LA and LAP also reduced oxidative stress and iron deposition in brain tissue. Furthermore, LA and LAP significantly ameliorated brain edema, blood-brain barrier injury, cortical apoptosis, and neurological behavior impairment induced by SAH. Finally, it is noteworthy that LAP exerted more significant effects than LA on these parameters as described above. LAP probably exerted neuroprotective effects via targeting lysosomes and chelating intralysosomal iron in EBI post-SAH in rats.

Hydrogen Sulfide Ameliorates Early Brain Injury Following Subarachnoid Hemorrhage in Rats

“…An autologous blood SAH model was performed as previously reported [25]. Briefly, 0.3-ml nonheparinized autologous arterial blood was slowly injected into the prechiasmatic cistern for SAH group, while 0.3-ml saline for sham group.…”

“…The index of brain edema and BBB injury were, respectively, evaluated by wet/dry method and Evans blue (EB) extravasation as described previously [25].…”

“…After treatment, all the rats were examined for behavioral impairment using a previously published scoring system and monitored for appetite, activity, and neurological defects ( Table 1) [25].…”

“…The concentration of reactive oxygen species (ROS) and malondialdehyde (MDA) and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the brain were measured by corresponding detection kits (Nanjing Jiancheng Bioengineering Institute, Nanjing, JS, China) according to the manufacturers' instructions as described in previous study [25].…”

“…Accumulating evidence has demonstated that H 2 S, as a kind of protective gas, exerted modulatory and cytoprotective effects on a variety of organs, including the heart, liver, lung, and kidney against ischemia-reperfusion (I/R) injury [16][17][18][19][20][21][22][23][24][25][26][27][28]. H 2 S is also known to significantly reduce cerebral I/R injury in the animal model [19][20][21][22][23].…”