Neuroprotective Effects of Early Hypothermia Induced by Phenothiazines and DHC in Ischemic Stroke.

METHODS: Adult male Sprague Dawley rats were studied in 4 groups: (1) sham; (2) stroke; (3) stroke treated with pharmacological hypothermia before reperfusion (interischemia hypothermia); and (4) stroke treated with pharmacological hypothermia after reperfusion is initiated (inter-reperfusion hypothermia). The combination of chlorpromazine and promethazine with dihydrocapsaicin (DHC) was used to induce hypothermia. To compare the neuroprotective effects of drug-induced hypothermia between the interischemia and inter-reperfusion groups, brain damage was evaluated using infarct volume and neurological deficits at 24 h reperfusion. In addition, mRNA expressions of NADPH oxidase (NOX) subunits (gp91phox, p67phox, p47phox, and p22phox) and glucose transporter subtypes (GLUT1 and GLUT3) were determined by real-time PCR at 6 and 24 h reperfusion. ROS production was measured by flow cytometry assay at the same time points. RESULTS: In both hypothermia groups, the cerebral infarct volumes and neurological deficits were reduced in the ischemic rats. At 6 and 24 h reperfusion, ROS production and the expressions of NOX subunits and glucose transporter subtypes were also significantly reduced in both hypothermia groups as compared to the ischemic group. While there were no statistically significant differences between the two hypothermia groups at 6 h reperfusion, brain damage was significantly further decreased by interischemia hypothermia at 24 h. CONCLUSION: Both interischemia and inter-reperfusion pharmacological hypothermia treatments play a role in neuroprotection after stroke. Interischemia hypothermia treatment may be better able to induce stronger neuroprotection after ischemic stroke. This study provides a new avenue and reference for stronger neuroprotective hypothermia before vascular recanalization in stroke patients.

Normobaric oxygen therapy attenuates hyperglycolysis in ischemic stroke.

Normobaric oxygen therapy has gained attention as a simple and convenient means of achieving neuroprotection against the pathogenic cascade initiated by acute ischemic stroke. The mechanisms underlying the neuroprotective efficacy of normobaric oxygen therapy, however, have not been fully elucidated. It is hypothesized that cerebral hyperglycolysis is involved in the neuroprotection of normobaric oxygen therapy against ischemic stroke. In this study, Sprague-Dawley rats were subjected to either 2-hour middle cerebral artery occlusion followed by 3- or 24-hour reperfusion or to a permanent middle cerebral artery occlusion event. At 2 hours after the onset of ischemia, all rats received either 95% oxygen normobaric oxygen therapy for 3 hours or room air. Compared with room air, normobaric oxygen therapy significantly reduced the infarct volume, neurological deficits, and reactive oxygen species and increased the production of adenosine triphosphate in ischemic rats. These changes were associated with reduced transcriptional and translational levels of the hyperglycolytic enzymes glucose transporter 1 and 3, phosphofructokinase 1, and lactate dehydrogenase. In addition, normobaric oxygen therapy significantly reduced adenosine monophosphate-activated protein kinase mRNA expression and phosphorylated adenosine monophosphate-activated protein kinase protein expression. These findings suggest that normobaric oxygen therapy can reduce hyperglycolysis through modulating the adenosine monophosphate-activated protein kinase signaling pathway and alleviating oxidative injury, thereby exhibiting neuroprotective effects in ischemic stroke. This study was approved by the Institutional Animal Investigation Committee of Capital Medical University (approval No. AEEI-2018-033) on August 13, 2018.

PM2.5 induces liver fibrosis via triggering ROS-mediated mitophagy.

BACKGROUND: The increasing epidemic of fine particulate matter (PM2.5) is a serious threat to human health. It induces the occurrence of liver fibrosis, but its molecular mechanism is not yet clear. The molecular mechanisms of PM2.5 inducing liver fibrosis were investigated in this study. METHODS: The cell viability of LX-2 cells and primary hepatic stellate cells (HSCs) was detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In vitro enzyme-linked immune sorbent assay (ELISA) kits were used to detect the concentrations of antioxidant enzymes and reactive oxygen species (ROS). The mitochondrial transmembrane potential (MTP) was determined by JC-1 dye. Knockdown of Parkin was carried out by Parkin-specific siRNA transfection. Relative mRNA and protein expressions were evaluated by qRT-PCR, Western blotting, and immunofluorescence analysis. RESULTS: PM2.5 activated LX-2 cells and primary HSCs, inducing the liver fibrosis along with down-regulation of the gelatinases MMP-2, and up-regulation of myofibroblast markers collagen type I and α-SMA. The levels of ROS and reactive nitrogen species (RNS), as well as the lipid peroxidation marker malondialdehyde (MDA) were significantly up-regulated in LX-2 cells and primary HSCs treated with PM2.5. Also, the enzymatic antioxidants levels were disturbed by PM2.5. Furthermore, PM2.5 decreased the MTP, releasing cytochrome c from the mitochondria to the cytosol. The dynamics of mitochondria were regulated by PM2.5 via facilitating mitochondrial fission. The excess ROS induced by PM2.5 triggered the mitophagy by activating PINK1/Parkin pathway, and inhibition of mitophagy induced by PM2.5 diminished the liver fibrosis. CONCLUSION: PM2.5 may induce mitophagy via activating PINK1/Parking signal pathway by increasing ROS, thereby activating HSCs and causing liver fibrosis.

Remote Ischemic Preconditioning-Mediated Neuroprotection against Stroke is Associated with Significant Alterations in Peripheral Immune Responses.

AIMS: Remote ischemic preconditioning (RIPC) of a limb is a clinically feasible strategy to protect against ischemia-reperfusion injury after stroke. However, the mechanism underlying RIPC remains elusive. METHODS: We generated a rat model of noninvasive RIPC by four repeated cycles of brief blood flow constriction (5 min) in the hindlimbs using a tourniquet. Blood was collected 1 h after preconditioning and 3 days after brain reperfusion. The impact of RIPC on immune cell and cytokine profiles prior to and after transient middle cerebral artery occlusion (MCAO) was assessed. RESULTS: Remote ischemic preconditioning protects against focal ischemia and preserves neurological functions 3 days after stroke. Flow cytometry analysis demonstrated that RIPC ameliorates the post-MCAO reduction of CD3(+)CD8(+) T cells and abolishes the reduction of CD3(+)/CD161a(+) NKT cells in the blood. In addition, RIPC robustly elevates the percentage of B cells in peripheral blood, thereby reversing the reduction in the B-cell population after stroke. RIPC also markedly elevates the percentage of CD43(+)/CD172a(+) noninflammatory resident monocytes, without any impact on the percentage of CD43(-)/CD172a(+) inflammatory monocytes. Finally, RIPC induces IL-6 expression and enhances the elevation of TNF-α after stroke. CONCLUSION: Our results reveal dramatic immune changes during RIPC-afforded neuroprotection against cerebral ischemia.