Schisandrin B Protects against Ischemic Brain Damage by Regulating PI3K/AKT Signaling in Rats / 中国结合医学杂志

OBJECTIVE@#To explore the effect and mechanism of schisandrin B (Sch B) in the treatment of cerebral ischemia in rats.@*METHODS@#The cerebral ischemia models were induced by middle cerebral artery occlusion (MCAO) and reperfusion. Sprague-Dawley rats were divided into 6 groups using a random number table, including sham, MCAO, MCAO+Sch B (50 mg/kg), MCAO+Sch B (100 mg/kg), MCAO+Sch B (100 mg/kg)+LY294002, and MCAO+Sch B (100 mg/kg)+wortmannin groups. The effects of Sch B on pathological indicators, including neurological deficit scores, cerebral infarct volume, and brain edema, were subsequently studied. Tissue apoptosis was identified by terminal transferase-mediated dUTP nick end-labeling (TUNEL) staining. The protein expressions involved in apoptosis, inflammation response and oxidative stress were examined by immunofluorescent staining, biochemical analysis and Western blot analysis, respectively. The effect of Sch B on phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling was also explored.@*RESULTS@#Sch B treatment decreased neurological deficit scores, cerebral water content, and infarct volume in MCAO rats (P<0.05 or P<0.01). Neuronal nuclei and TUNEL staining indicated that Sch B also reduced apoptosis in brain tissues, as well as the Bax/Bcl-2 ratio and caspase-3 expression (P<0.01). Sch B regulated the production of myeloperoxidase, malondialdehyde, nitric oxide and superoxide dismutase, as well as the release of cytokine interleukin (IL)-1 β and IL-18, in MCAO rats (P<0.05 or P<0.01). Sch B promoted the phosphorylation of PI3K and AKT. Blocking the PI3K/AKT signaling pathway with LY294002 or wortmannin reduced the protective effect of Sch B against cerebral ischemia (P<0.05 or P<0.01).@*CONCLUSIONS@#Sch B reduced apoptosis, inflammatory response, and oxidative stress of MCAO rats by modulating the PI3K/AKT pathway. Sch B had a potential for treating cerebral ischemia.

Schisandrin B Inhibits NLRP3 Inflammasome Pathway and Attenuates Early Brain Injury in Rats of Subarachnoid Hemorrhage / 中国结合医学杂志

OBJECTIVE@#To determine whether Schisandrin B (Sch B) attenuates early brain injury (EBI) in rats with subarachnoid hemorrhage (SAH).@*METHODS@#Sprague-Dawley rats were divided into sham (sham operation), SAH, SAH+vehicle, and SAH+Sch B groups using a random number table. Rats underwent SAH by endovascular perforation and received Sch B (100 mg/kg) or normal saline after 2 and 12 h of SAH. SAH grading, neurological scores, brain water content, Evan's blue extravasation, and terminal transferase-mediated dUTP nick end-labeling (TUNEL) staining were carried out 24 h after SAH. Immunofluorescent staining was performed to detect the expressions of ionized calcium binding adapter molecule 1 (Iba-1) and myeloperoxidase (MPO) in the rat brain, while the expressions of B-cell lymphoma 2 (Bcl-2), Bax, Caspase-3, nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3), apoptosis-associated specklike protein containing the caspase-1 activator domain (ASC), Caspase-1, interleukin (IL)-1β, and IL-18 in the rat brains were detected by Western blot.@*RESULTS@#Compared with the SAH group, Sch B significantly improved the neurological function, reduced brain water content, Evan's blue content, and apoptotic cells number in the brain of rats (P<0.05 or P<0.01). Moreover, Sch B decreased SAH-induced expressions of Iba-1 and MPO (P<0.01). SAH caused the elevated expressions of Bax, Caspase-3, NLRP3, ASC, Caspase-1, IL-1β, and IL-18 in the rat brain (P<0.01), all of which were inhibited by Sch B (P<0.01). In addition, Sch B increased the Bcl-2 expression (P<0.01).@*CONCLUSION@#Sch B attenuated SAH-induced EBI, which might be associated with the inhibition of neuroinflammation, neuronal apoptosis, and the NLRP3 inflammatory signaling pathway.

Baicalin Reduces Early Brain Injury after Subarachnoid Hemorrhage in Rats / 中国结合医学杂志

OBJECTIVE@#To evaluate the effect of baicalin on subarachnoid hemorrhage (SAH) in rats and explore the potential mechanisms.@*METHODS@#Sprague-Dawley rats underwent experimental SAH and received treatment with baicalin at 10 or 50 mg/kg after 2 and 12 h of SAH. Neurological scores, brain water content, Evans-blue extravasation, and levels of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), myeloperoxidase (MPO), and malondialdehyde (MDA) were measured 24 h after SAH. Expression of nuclear factor erythroid-related factor 2 (Nrf2), NAD(P)H: quinone oxidoreductase 1 (NQO1), matrix metalloproteinase-9 (MMP-9), aquaporin 4 (AQP4), occludin, and zonulaoccludens-1 (ZO-1) were detected in the brain by Western blot. Heme oxygenase-1 (HO-1) was detected by quantitative polymerase chain reaction, and tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were assessed by enzyme-linked immunosorbent assay.@*RESULTS@#Baicalin attenuated EBI 24 h after SAH in rats (P<0.05). Baicalin elevated neurological scores, GSH-Px, SOD, and increased the expression of Nrf2, NQO1, HO-1, occludin, and ZO-1 in SAH rats (P<0.05 or P<0.01). Baicalin reduced MPO, MDA, and the expression of MMP-9, AQP4, TNF-α, and IL-1β (P<0.05 or P<0.01).@*CONCLUSION@#Baicalin reduced SAH-induced EBI, partially via activation of the Nrf2/HO-1 pathway and inhibition of MMP-9 and AQP4.

Propofol attenuates neuroinflammation and brain damage via modulating PI3K/Akt signaling pathway in rats of focal cerebral ischemia / 中国药理学通报

Aim To explore whether propofol attenuates neuroinflammation and brain damage via modulating PI3K/Akt signaling pathway following focal cerebral ischemia in rats, and further investigate the possible mechanisms. Methods Sprague-Dawley rats which underwent the cerebral ischemic injury by the suture occlusion model were randomly divided into sham operation, MCAO, propofol-treated and LY294002 groups. Neurological deficit scores, cerebral infarct size, and cerebral water content were measured , then the myeloperoxidase (MPO) activities in rat brain were measured as an index of neutrophil infiltration. The content of TNF-α and IL-1β in blood was determined using ELISA; the expressions of p-Akt and Akt in rat brain were detected by Western blot. Results Propofol reduced neurological deficit scores, cerebral infarct size, cerebral water content, MPO activity , TNF-α and IL-1β content, which were all abolished by LY294002. Propofol up-regulated the expression of p-Akt, which was inhibited by LY294002. Conclusion Propofol attenuates neuroinflammation and ischemic brain damage via modulating the PI3K/Akt signaling pathway.

Changes of cortical somatosensory evoked potentials under different levels of ischemia in the spinal cord / 中华神经医学杂志

Objective To provide the theoretical basis for the application of cortical somatosensory evoked potential (CSEP) in monitoring the function of the spinal cord to prevent postoperative neurological dysfunction. Methods Thirty-three New Zealand rabbits were randomly divided into 6 groups: 8 were chosen as control group to eliminate the influence of anesthesia and surgery on the evoked potential; the other 25 were assigned to 5 sub-experimental groups (n=5) according to the artery number being ligatured in the left renal arteries and the spinal arteries. Baseline evoked potential in each group was noted immediately after anesthesia; the CSEP were recorded at different time points (before vascular ligation, 30 min and 2 d after vascular ligation). Motor functions were assessed after narcotic conscious and 2 d after vascular ligation. The specimens were taken for HE staining. Results The latency was not sensitive to spinal cord ischemia and no significant difference of that was found between the experimental groups and the control group (P>0.05); except that, the changes of theamplitudes were very complex and the specificity of motor function was decreased. The amplitude reduced and then gradually restored in the 2, 3 and 4 levels of ligation. The changes of amplitude could indicate the degree of pathological damage in the spinal cord and its motor function. Conclusion Complex amplitude of somatosensory evoked potential can be found in the acute phase of ischemia in the spinal cord. Specificity of motor function is poor resulting from its signal averaging process. Motor evoked potential monitoring in the operation should also be added in the detection of the spinal cord.