The role of Rho/Rho-kinase pathway and the neuroprotective effects of fasudil in chronic cerebral ischemia

The Rho/Rho-kinase signaling pathway plays an important role in cerebral ischemia/reperfusion injury. However, very few studies have examined in detail the changes in the Rho/Rho-kinase signaling pathway in chronic cerebral ischemia. In this study, rat models of chronic cerebral ischemia were established by permanent bilateral common carotid artery occlusion and intra- gastrically administered 9 mg/kg fasudil, a powerful ROCK inhibitor, for 9 weeks. Morris water maze results showed that cognitive impairment progressively worsened as the cerebral ischemia proceeded. Immunohistochemistry, semi-quantitative RT-PCR and western blot analysis showed that the expression levels of Rho-kinase, its substrate myosin-binding subunit, and its relat- ed protein alpha smooth muscle actin, significantly increased after chronic cerebral ischemia. TUNEL staining showed that chronic cerebral ischemia could lead to an increase in neuronal apoptosis, as well as the expression level of caspase-3 in the frontal cortex of rats subjected to chronic cerebral ischemia. Fasudil treatment alleviated the cognitive impairment in rats with chronic cerebral ischemia, and decreased the expression level of Rho-kinase, myosin-binding subunit and alpha smooth muscle actin. Furthermore, fasudil could regulate cerebral injury by reducing cell apoptosis and decreasing caspase-3 expression in the frontal cortex. These findings demonstrate that fasudil can protect against cognitive impairment induced by chronic cerebral ischemia via the Rho/Rho-kinase signaling pathway and anti-apoptosis mechanism.

Changes of hypoxia-inducible factor-1 signaling and the effect of cilostazol in chronic cerebral ischemia

Hypoxiainducible factor1 and its specific target gene heme oxygenase1, are involved in acute cerebral ischemia. However, very few studies have examined in detail the changes in the hy poxiainducible factor1/heme oxygenase1 signaling pathway in chronic cerebral ischemia. In this study, a rat model of chronic cerebral ischemia was established by permanent bilateral common carotid artery occlusion, and these rats were treated with intragastric cilostazol （30 mg/kg） for 9 weeks. Morris water maze results showed that cognitive impairment gradually worsened as the cerebral ischemia proceeded. Immunohistochemistry, semiquantitative PCR and western blot analysis showed that hypoxiainducible factorla and heme oxygenase1 expression levels in creased after chronic cerebral ischemia, with hypoxiainducible factorla expression peaking at 3 weeks and heme oxygenase1 expression peaking at 6 weeks. These results suggest that the elevated levels of hypoxiainducible factorla may upregulate heine oxygenase1 expression fol lowing chronic cerebral ischemia and that the hypoxiainducible factor1/heme oxygenase1 sig naling pathway is involved in the development of cognitive impairment induced by chronic cerebral ischemia. Cilostazol treatment alleviated the cognitive impairment in rats with chronic cerebral ischemia, decreased hypoxiainducible factorla and heme oxygenase1 expression levels, and reduced apoptosis in the frontal cortex. These findings demonstrate that cilostazol can protect against cognitive impairment induced by chronic cerebral ischemic injury through an antiapoptotic mechanism.

Aerobic exercise combined with huwentoxin-I mitigates chronic cerebral ischemia injury

Ca2＋ channel blockers have been shown to protect neurons from ischemia, and aerobic exercise has significant protective effects on a variety of chronic diseases. The present study injected huwentoxin-I （HWTX-I）, a spider peptide toxin that blocks Ca2＋ channels, into the caudal vein of a chronic cerebral ischemia mouse model, once every 2 days, for a total of 15 injections. During this time, a subgroup of mice was subjected to treadmill exercise for 5 weeks. Results showed amelioration of cortical injury and improved neurological function in mice with chronic cerebral ischemia in the HWTX-I ＋ aerobic exercise group. The combined effects of HWTX I and exercise were superior to HWTX-I or aerobic exercise alone. HWTX-I effectively activated the Notch signal transduction pathway in brain tissue. Aerobic exercise up-regulated synaptophysin mRNA expression. These results demonstrated that aerobic exercise, in combination with HWTX-I, effectively relieved neuronal injury induced by chronic cerebral ischemia via the Notch signaling pathway and promoting synaptic regeneration.

Neuroprotective effects of kaempferol against 2VO-induced chronic cerebral ischemia in rats

OBJECTIVE To investigate the effects of kaempferol(KAE)on chronic cerebral ischemia in rats.METHODS Chronic cerebral ischemia was induced in rats by permanent occlusion of bilateral common carotid arteries(2VO).Then,the rats with chronic cerebral ischemia were randomly divied into three groups:model group,KAE 10 and 30 mg·kg-1group.Another group rats without occlusion of common carotid arteries were used as the sham-operation group.Memory behavior was investigated by Morris water maze test.Prehensile ability was investigated by prehensile traction test.The structure of hippocampus and cortex neurons was observed with Nissel staining.In addition,the SOD activity and MDA content in brain tissue were determined.The DJ-1protein level was determined by Western blotting.RESULTS KAE 10 and 30 mg·kg-1could significantly improve cognitive impairment and prehensile traction ability(P<0.01)induced by chronic cerebral ischemia in rats.The results of the pathological analysis also suggested that KAE could ameliorate the pathological damage induced by chronic cerebral ischemia.In addition,KAE 30 mg·kg-1significantly increased the activity of SOD(P<0.05),but had no effect on the content of MDA in rat brain tissue.Western-blotting confirmed that KAE 10 and30 mg·kg-1could increase the expression of anti-oxidation proteins DJ-1 in hippocampus(P<0.01).CONCLUSION KAE may attenuate the chronic cerebral ischemic injury in rats.

Estrogen intervention in microvascular morphology and choline acetyltransferase expression in rat hippocampal neurons in chronic cerebral ischemia

We observed dynamic changes in microvessels and a protective effect of estrogen on chronic cerebral ischemia ovariectomized rat models established through permanent occlusion of bilateral carotid arteries at 7, 14 and 21 days. The results revealed that estrogen improved microvasculature in the hippocampus of chronic cerebral ischemic rats, upregulated Bcl-2 protein expression, downregulated Bax protein expression, increased choline acetyltransferase expression in hippocampal cholinergic neurons, and suppressed hippocampal neuronal apoptosis. These findings indicate that estrogen can protect hippocampal neurons in rats with chronic cerebral ischemia.

Effect of propofol on brain-derived neurotrophic factor and tyrosine kinase receptor B in the hippocampus of aged rats with chronic cerebral ischemia

We intraperitoneally injected 10 and 50 mg/kg of propofol for 7 consecutive days to treat a rat model of chronic cerebral ischemia. A low-dose of propofol promoted the expression of brain-derived neurotrophic factor, tyrosine kinase receptor B, phosphorylated cAMP response element binding protein, and cAMP in the hippocampus of aged rats with chronic cerebral ischemia, but a high-dose of propofol inhibited their expression. Results indicated that the protective effect of propofol against cerebral ischemia in aged rats is related to changes in the expression of brain-derived neurotrophic factor and tyrosine kinase receptor B in the hippocampus, and that the cAMP-cAMP responsive element binding protein pathway is involved in the regulatory effect of propofol on brain-derived neurotrophic factor expression.

Curcumin alters expression of glial fibrillary acidic protein and nestin following chronic cerebral ischemia

Astrocytes can alter their appearance and become reactive following chronic cerebral ischemia. In the present study, a rat model of chronic cerebral ischemia was treated with 50 and 100 mg/kg curcumin. Results showed that pathological changes of neuronal injury in hippocampal CA1 area of rats induced by chronic cerebral ischemia were attenuated, as well as upregulated expression of glial fibriliary acidic protein and nestin, in a dose-dependent manner.

Intercellular adhesion molecule-1 expression in the hippocampal CA1 region of hyperlipidemic rats with chronic cerebral ischemia

Chronic cerebral ischemia is a pathological process in many cerebrovascular diseases and it is induced by long-term hypedipidemia, hypertension and diabetes mellitus. After being fed a high-fat diet for 4 weeks, rats were subjected to permanent occlusion of bilateral common carotid arteries to establish rat models of chronic cerebral ischemia with hypedipiclemia. Intercellular adhesion molecule-1 expression in rat hippocampal CA1 region was determined to better understand the mechanism underlying the effects of hypedipidemia on chronic cerebral ischemia. Water maze test results showed that the cognitive function of rats with hyperlipidemia or chronic cerebral ischemia, particulady in rats with hypedipidemia combined with chronic cerebral ischemia, gradually decreased between 1 and 4 months after occlusion of the bilateral common carotid arteries. This correlated with pathological changes in the hippocampal CA1 region as detected by hematoxylin-eosin staining. Immunohistochemical staining showed that intercellular adhesion molecule-1 expression in the hippocampal CA1 region was noticeably increased in rats with hyperlipidemia or chronic cerebral ischemia, in particular in rats with hyperlipidemia combined with chronic cerebral ischemia. These findings suggest that hyperlipidemia aggravates chronic cerebral ischemia-induced neurological damage and cognitive impairment in the rat hippocampal CA1 region which may be mediated, at least in part, by up-regulated expression of intercellular adhesion molecule-l.

Mechanism underlying the protective effect of Kaixin Jieyu Fang on vascular depression following cerebral white matter damage

The Chinese compound Kaixin fieyu Fang can be used to treat vascular depression; however, the underlying mechanism remains unclear. This study established a rat model of chronic cerebral ischemia-caused white matter damage by ligation of the bilateral common carotid arteries. Rats received daily intragastric administration of a suspension of Kaixin ]ieyu Fang powder. After 3, 7 and 21 days of treatment, the degree of white matter damage in the cerebral ischemia rat model was alleviated, Bcl-2 protein and mRNA expression in brain tissue increased, and Bax protein and mRNA expression decreased. These results indicate that Kaixin Jieyu Fang can alleviate cere- bral white matter damage, and the underlying mechanism is associated with regulation of Bcl-2/ Bax protein and mRNA expression, which is one of possible mechanism behind the protective effect of Kaixin Jieyu Fang against vascular depression.

Qinzhi Zhudan formula improves memory and alleviates neuroinflammation in vascular dementia rats partly by inhibiting the TNFR1-mediated TNF pathway

Objective: The Qinzhi Zhudan formula(QZZD) exhibits a prominent therapeutic effect in the treatment of vascular dementia(VaD). This study combined a network pharmacology approach and experimental validation to identify the underlying biological mechanism of QZZD against VaD.Methods: Male Wistar rats received bilateral common carotid artery occlusion(BCCAO) surgery, and after4 weeks of intragastric administration of QZZD, the therapeutic effect was assessed using the Morris water maze test and cerebral blood flow(CBF) assessment. Hematoxylin and eosin staining, Nissl staining, and electron microscopy were used to measure the histopathological changes in the neurons of rats. The effect of QZZD treatment on hippocampal neurotransmitters was assessed by high-performance liquid chromatography with electrochemical detection and liquid chromatography mass spectrometry.Immunofluorescence was used to observe VaD-induced microglia activation. The inflammatory cytokine levels were assessed by enzyme linked immunosorbent assay. Western blot was used to examine the TNFR1-mediated TNF pathway, which was screened out by network pharmacology analysis.Results: QZZD treatment alleviated pathological changes and neuronal damage in VaD rats and attenuated their cognitive impairment. In addition, QZZD increased CBF and the expression of acetylcholine and 5-hydroxytryptamine in the hippocampal region. Notably, QZZD inhibited microglial activation and the expression of IL-6 and TNF-a. Network pharmacology and western blot indicated that QZZD inhibited the levels of TNFR1, NF-κBp65, p-ERK, TNF-a, and IL-6, which are related to the TNFR1-mediated TNF signaling pathway.Conclusion: QZZD clearly improved learning and memory function, reduced brain pathological damage,elevated CBF and hippocampal neurotransmitter levels, and alleviated neuroinflammation of VaD rats partly by inhibiting the TNFR1-mediated TNF pathway, indicating its potential value in the clinical therapy of VaD.