Genistein-3'-sodium sulfonate ameliorates cerebral ischemia injuries by blocking neuroinflammation through the α7nAChR-JAK2/STAT3 signaling pathway in rats.

BACKGROUND: Neuroinflammation plays a pivotal role in the acute progression of cerebral ischemia/reperfusion injury (I/RI). We previously reported that genistein-3'-sodium sulfonate (GSS), a derivative from the extract of the phytoestrogen genistein (Gen), protects cortical neurons against focal cerebral ischemia. However, the molecular mechanism underlying the neuroprotective effects exerted by GSS remains unclear. PURPOSE: The present study focused on the anti-inflammatory effects of GSS following I/RI in rats. STUDY DESIGN: Randomized controlled trial. METHODS: The tMCAO rat model and LPS-stimulated BV2 in vitro model were used. Longa's scare was used to observe neurological function. TTC staining and Nissl staining were used to evaluate brain injury. ELISA, qRT-PCR, Western blotting and immunofluorescent staining methods were used to detect cytokine concentration, mRNA level, protein expression and location. RESULTS: GSS treatment improves neurological function, reduces the volume of cerebral infarction, attenuates proinflammatory cytokines and inactivates the phosphorylation of JAK2 and STAT3 in I/RI rats. Furthermore, GSS increased the expression of α7nAChR. More importantly, the neuroprotective, anti-inflammatory and inhibiting JAK2/STAT3 signaling pathway effects of GSS were counteracted in the presence of alpha-bungarotoxin (α-BTX), an α7nAChR inhibitor, suggesting that α7nAChR is a potential target associated with the anti-inflammatory effects of GSS in the I/RI rats. GSS also inhibited BV2 cells from releasing IL-1ß via the α7nAChR pathway after LPS stimulation. CONCLUSION: GSS protects against cerebral I/RI through the expression of α7nAChR and inhibition of the JAK2/STAT3 pathway. Our findings provide evidence for the role of the cholinergic anti-inflammatory pathway in neuroinflammation and uncover a potential novel mechanism for GSS treatment in ischemic stroke. The downstream signals of GSS, α7nAChR- JAK2/STAT3 could also be potential targets for the treatment of I/RI.

Genistein-3'-sodium sulfonate Attenuates Neuroinflammation in Stroke Rats by Down-Regulating Microglial M1 Polarization through α7nAChR-NF-κB Signaling Pathway.

Microglial M1 depolarization mediated prolonged inflammation contributing to brain injury in ischemic stroke. Our previous study revealed that Genistein-3'-sodium sulfonate (GSS) exerted neuroprotective effects in ischemic stroke. This study aimed to explore whether GSS protected against brain injury in ischemic stroke by regulating microglial M1 depolarization and its underlying mechanisms. We established transient middle cerebral artery occlusion and reperfusion (tMCAO) model in rats and used lipopolysaccharide (LPS)-stimulated BV2 microglial cells as in vitro model. Our results showed that GSS treatment significantly reduced the brain infarcted volume and improved the neurological function in tMCAO rats. Meanwhile, GSS treatment also dramatically reduced microglia M1 depolarization and IL-1ß level, reversed α7nAChR expression, and inhibited the activation of NF-κB signaling in the ischemic penumbra brain regions. These effects of GSS were further verified in LPS-induced M1 depolarization of BV2 cells. Furthermore, pretreatment of α7nAChR inhibitor (α-BTX) significantly restrained the neuroprotective effect of GSS treatment in tMCAO rats. α-BTX also blunted the regulating effects of GSS on neuroinflammation, M1 depolarization and NF-κB signaling activation. This study demonstrates that GSS protects against brain injury in ischemic stroke by reducing microglia M1 depolarization to suppress neuroinflammation in peri-infarcted brain regions through upregulating α7nAChR and thereby inhibition of NF-κB signaling. Our findings uncover a potential molecular mechanism for GSS treatment in ischemic stroke.

Effect of PBNA on the NO content and NOS activity in ischemia/reperfusion injury in the rat retina.

OBJECTIVE: To investigated the effect of Polygonum Bistorta L. n-butyl Alcohol (PBNA) extract on the NO content and NOS activity in ischemia/reperfusion (I/R) injury in the rat retina. METHODS: The model of retinal I/R injury in SD rats was made by reperfusion for 1 h after occlusion of common carotid artery (CCA) for 1 h. The rats were randomly divided into four groups: control group, retinal I/R injury group, low-dosage PBNA treated group and high-dosage treated PBNA group. The control group was injected with 1 ml/kg NS through sublingual vein after CCA was dissociated. Other groups were treated with normal saline or PBNA before occlusion of CCA. After occlusion of CCA for 1 h following reperfusion for 1 h, blood was collected and serum was separated to determine the contents of NO, the activity of T-NOS, iNOS and eNOS. RESULT: (1) The contents of NO in I/R group showed lower values than in control group (P<0.001) and low-dosage PBNA treated group (P<0.05). (2) The activities of T-NOS in both low-dosage PBNA group and high-dosage group increased, compared with I/R group (P<0.01). (3) The activity of serum iNOS in I/R group increased compared with control group (P<0.05) and low-dosage PBNA treated group evidently (P<0.05). (4) The activity of serum eNOS in I/R group decreased compared with control group (P<0.05), both low-dosage (P<0.05) and high-dosage PBNA (P<0.01) treated group markedly. CONCLUSION: The date suggest that PBNA have a therapeutic effect on retinal ischemia/reperfusion injury by increasing the activities of T-NOS and eNOS, decreasing the activity of iNOS, elevating the content of NO, enhancing the Anti-oxidation and expanding the blood vessel.