The protective role of Tongxinluo on blood-brain barrier after ischemia-reperfusion brain injury.

Tongxinluo (TXL), a renowned traditional Chinese medicine, consists of several different kinds of ingredients and has been widely used to treat myocardial infarction and ischemic stroke. However, the underlying neuroprotective mechanisms are not fully understood. We focus on the effect of TXL on blood-brain barrier (BBB) including edema formation and tight junction (TJ) protein rearrangement, and inflammatory response after transient middle cerebral artery occlusion (tMCAO). We further explore the protective mechanism of TXL on ischemia-induced BBB damage. Adult CD1 male mice (n=168) were randomly divided into TXL pre-treatment group, TXL pre-post treatment group, TXL post-treatment group, control group and sham group. Mice in TXL pre-treatment group were given TXL solution by 1g/kg/day orally for 7 days before tMCAO. Mice in pre-post treatment group were continuously given TXL 7 days before and 14 days after tMCAO. Mice in TXL post-treatment group were given TXL solution immediately after tMCAO. Rotarod test and neurological severity scores were evaluated at 1-14 days following tMCAO. Brains were harvested for examining infarct volume, edema formation, and immunofluorescent staining at 1 and 3 days after tMCAO. Cytokines IL-6, IL-1β and TNF-α mRNA expression, and BBB permeability were further examined by RT-PCR and immunostaining. TXL pre-post treatment improved neurobehavioral outcomes and reduced infarct volume compared to the control (p<0.05). Meanwhile, hemispheric swelling, Evans blue and IgG protein extravasation reduced, while TJ protein expression up-regulated in pre-post treatment group (p<0.05). Further study indicated that infarct volume was smaller and BBB damage was less severe in TXL pre-post treatment group compared to TXL pre-treatment alone. It was noted that fewer myeloperoxidase (MPO) positive cells and less cytokines IL-6, IL-1β and TNF-α expression in pre-post treatment group compared to the control group (p<0.05). TXL pre-treatment and pre-post treatment effectively protected the brain from BBB disruption via alleviating inflammatory response. Moreover, pre-post treatment has better outcomes, suggesting that continuous administration of TXL before and throughout ischemia period is necessary because of multiple functions of TXL.

Liu Y ，Tang GH ，Sun YH ，Lin XJ ，Wei C ，Yang GY ，Liu JR ... -  《-》

Tongxinluo reduces brain edema and inhibits post-ischemic inflammation after middle cerebral artery occlusion in rats.

Tongxinluo (TXL), a widely used traditional Chinese medicine, has been proved multiple therapeutic effects in cerebral ischemic infraction. The purpose of this study was to investigate the protective effects of TXL on the brain edema and post-ischemic inflammatory response. Middle cerebral artery occlusion in the rat was used as the ischemia model. Rats were treated with TXL. In the first stage, the best dosage was chosen based on functional assessment and infarct size. In the second stage, rats were randomly divided into 5 groups: sham control (sham), ischemia and reperfusion (IR) 24h, TXL24h, I/R72h, TXL72h. TXL(1.6g/kg/day) administration was pre-performed for 3 days in TXL groups, and was post-performed for 24h (TXL24h group) or 72h (TXL72h group). Brain edema was measured by water content, MRI and AQP4 expression. Iba1, HMGB1, TLR4, NF-κB expression were examined by immunofluorescence staining or Western blot. TNF-α was determined by enzyme-linked immunosorbent assay. High dose (1.6g/kg/day) of TXL remarkably reduced neurological deficit scores and cerebral infarct area. Compared with those results of I/R24h group, pre-post treatment with TXL for 3 days decreased brain water content, down-regulated AQP4 expression, lowered relative signal intensity of T2WI, reduced lesion volume ratio, and inhibited the activation of microglia, HMGB1, TLR4, NF-κB and TNF-α. These results indicated that the TXL pre-post treatment for 3 days could be an effective therapy for brain ischemia by inhibiting the development of brain edema and post-ischemic inflammation.

Cai M ，Yu Z ，Wang L ，Song X ，Zhang J ，Zhang Z ，Zhang W ，Li W ，Xiang J ，Cai D ... -  《-》

PI3K/Akt pathway contributes to neuroprotective effect of Tongxinluo against focal cerebral ischemia and reperfusion injury in rats.

Tongxinluo (TXL), a compound prescription, is formulated according to the collateral disease doctrine of traditional Chinese medicine, and is widely used for the treatment of cardio-cerebrovascular diseases in China. We aimed to investigate the neuroprotective effect of TXL on focal cerebral ischemia and reperfusion injury in rats by attenuating its brain damage and neuronal apoptosis, and to assess the potential role of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway in this protection. Adult Male Sprague-Dawley rats (n=120) were randomly divided into 5 groups: sham, cerebral ischemia and reperfusion (I/R), cerebral ischemia and reperfusion plus TXL (1.6g/kg/day) (TXL1.6), TXL1.6 plus LY294002 and dimethyl sulfoxide (DMSO) (TXL1.6+LY294002), TXL1.6 plus DMSO (TXL1.6+vehicle). Prior to the grouping, TXL1.6 was selected to be the optimal dose of TXL by evaluating the neurological deficits score of five group rats (Sham, I/R, TXL0.4, TXL0.8 and TXL1.6, n=30) at 0, 1, 3, 5, and 7 days after reperfusion. Rats, being subjected to middle cerebral artery occlusion (MCAO) for 90min followed by 24h reperfusion, were the cerebral ischemia/reperfusion models. At 24h after reperfusion, cerebral infarct area was measured via tetrazolium staining and neuronal damage was showed by Nissl staining. The double staining of Terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick end labeling (TUNEL) staining and immunofluorescence labeling with NeuN, was performed to evaluate neuronal apoptosis. Proteins involved in PI3K/Akt pathway were detected by Western blot. The results showed that TXL markedly improved neurological function, reduced cerebral infarct area, decreased neuronal damage, and significantly attenuated neuronal apoptosis, while these effects were eliminated by inhibition of PI3K/Akt with LY294002. We also found that TXL up-regulated the expression levels of p-PDK1, p-Akt, p-c-Raf, p-BAD and down-regulated Cleaved caspase 3 expression notably, which were partially reversed by LY294002. Additionally, the increment of p-PTEN level on which LY294002 had little effect was also detected in response to TXL treatment. These findings demonstrated that TXL provided neuroprotection against cerebral ischemia/reperfusion injury and neuronal apoptosis, and this effect was mediated partly by activation of the PI3K/Akt pathway.

Yu ZH ，Cai M ，Xiang J ，Zhang ZN ，Zhang JS ，Song XL ，Zhang W ，Bao J ，Li WW ，Cai DF ... -  《-》

Protective effects of Tongxinluo on cerebral ischemia/reperfusion injury related to Connexin 43/Calpain II/Bax/Caspase-3 pathway in rat.

Tongxinluo (TXL) is a multifunctional traditional Chinese medicine and has been widely used in the treatment of cardiovascular and cerebrovascular diseases. Numerous studies demonstrate that TXL is a novel neuroprotective drug, however, the mechanisms are largely unknown. we aimed to demonstrate the protective effect of TXL on cerebral ischemia/reperfusion (I/R) injury and provide the evidence for the involvement of Connexin 43/Calpain II/ Bax/Caspase-3 pathway in TXL-mediated neuroprotection. Focal cerebral I/R injury were induced by transient middle cerebral artery occlusion (MCAO, for 90min) in adult male Sprague-Dawley rats. We estimated the effects of TXL on I/R injury including neurological deficit assessment and cerebral infarct volume measurement via TTC staining, and detected the protein expression of Connexin 43 (Cx43) by western blot. Furthermore, after the intracerebroventricular injection of carbenoxolone (CBX, the inhibitor of Cx43) at 30min before MCAO surgery, Calpain II, Bax and cleaved Caspased-3 immunoreactivity in ischemic penumbra region was detected by immunofluorescent staining, and cell apoptosis was detected by TUNEL staining. TXL treatment greatly improved neurological deficit and reduced the infarction volume compared to MCAO with buffer treatment (P<0.05), and TXL pre-post treatment showed better results than TXL pre-treatment. TXL pre-post treatment significantly up-regulated Cx43 protein expression at 3d, 7d and 14d post-injury compared to MCAO with buffer treatment (P<0.05). Meanwhile, the immunoreactivity of Calpain II, Bax and cleaved Caspase-3 in ischemic penumbra region was obviously decreased by TXL pre-post treatment compared to MCAO group (P<0.05). However, with the treatment of the Cx43 inhibitor, CBX, the down-regulated effect of TXL on Calpain II, Bax and cleaved Caspase-3 immunoreactivity was abolished (P<0.05). Moreover, the protective effect of TXL against neuron apoptosis in penumbra region was conteracted by CBX (P<0.05). TXL could effectively protect against I/R injury and reduced cell death via Cx43/Calpain II/Bax/Caspase-3 pathway, which contribute to I/R injury prevention and therapy.

Cheng X ，Hou Z ，Sun J ，Huang Y ，Wang L ，Zhou Z ，Zhou LH ，Cai Y ... -  《-》

Chinese medicine Tongxinluo capsule protects against blood-brain barrier disruption after ischemic stroke by inhibiting the low-density lipoprotein receptor-related protein 1 pathway in mice.

Chinese medicine Tongxinluo capsule (TXL) has been extensively used to treat ischemic stroke in China, and one of its mechanisms is to protect against blood brain barrier (BBB) disruption after stroke. However, the underlying protective mechanisms are not fully illuminated. It is reported that the low-density lipoprotein receptor-related protein 1 (LRP-1) is involved in BBB disruption after brain ischemia. In this study, we explored whether TXL could downregulate LRP-1 expression and subsequently protect against BBB disruption after stroke using permanent middle cerebral artery occlusion (pMCAO) in mice. The animal model of ischemic stroke was induced by pMCAO in male adult C57BL/6J mice. The mice were orally administered TXL (3.0 g/kg) at 1, 3 and 21 h after pMCAO. Meanwhile, the LRP-1 antagonist receptor associated protein (RAP) was intracerebroventricularly injected at 1 and 21 h after stroke. We measured the following parameters at 6 and 24 h: LRP-1 protein level, BBB leakage, and the expression of tight junction (TJ) proteins including occludin, claudin-5 and zonula occludens-1 (ZO-1). Our results showed that TXL downregulated LRP-1 level, upregulated these TJ proteins level, and reduced BBB leakage in peri-infarct regions after pMCAO. Further study found that the inhibitor RAP played the same role as did TXL in upregulating these TJ proteins level and reducing BBB leakage after stroke. Our study demonstrates that TXL protects against BBB disruption after stroke via inhibiting the LRP-1 pathway.

Chang L ，Hu L ，Wei C ，Zhang H ，Liu S ... -  《-》