Therapeutic effect of Ginkgo biloba polysaccharide in rats with focal cerebral ischemia/reperfusion (I/R) injury
Introduction
Acute ischemic stroke is one of the leading causes of adult disability and death in the world, and the majority of ischemic strokes results from occlusion of the middle cerebral artery, which leads to a reduction of cerebral blood flow in a specific region. Reperfusion of the tissue is associated with inflammation, increased reactive oxygen species, necrosis and apoptosis. Hence, damage to the brain will continue even after the blood flow is restored. Reperfusion after ischemia leads to profound cerebral microcirculatory disturbance and even death of neurons (Aronowski, Strong, & Grotta, 1997), thus protecting the brain from reperfusion injury after ischemia is an alternative for therapy of stroke. Although numerous interventions have been investigated, few neuroprotective agents have been successfully translated from basic research into clinical applications (Linares & Mayer, 2009). Thrombolytic therapy and intravascular techniques are recommended to restore blood flow to the brain in acute ischemic stroke but carries with the risk of hemorrhage and aggravates cerebral damage caused by reperfusion (Aronowski et al., 1997).
Over the past decade, intense interest has focused on discovering effective agents from medicinal plants, especially traditional Chinese herbal medicines (CHM), for the prevention and treatment of ischemic stroke, since many CHMs are reported to possess cardioprotective or neuroprotective activities (He et al., 2012, Huang et al., 2012, Sun et al., 2010). Therefore, a search for safe and effective agents from CHMs for management of ischemic brain injury is urgently needed.
The extract of Ginkgo biloba L. (Ginkgoaceae) has been extensively used in a variety of cardiovascular and cerebrovascular diseases such as ischemia, dementia, and depression (Ahlemeyer and Krieglstein, 2003, Gertz and Kiefer, 2004, Nishida and Satoh, 2004, Saleem et al., 2008, Sierpina et al., 2003). Although highly neuroprotective effects of G. biloba extract against ischemia/reperfusion (I/R) injury has been well proven (Krieglstein et al., 1995, Wang et al., 1998), the mechanism and mode underlying the therapeutic effects is still under investigation. It has been revealed that neuroprotection action of G. biloba extract during cerebral I/R injury might be related to two major groups, namely flavonols and lactones (Cho et al., 2009, Dubber and Kanfer, 2004), while nothing is known about the neuroprotective effect of purified water-soluble G. biloba polysaccharide on I/R-induced cerebral injury. Therefore the present study was undertaken to purify the polysaccharide from this plant and investigate its neuroprotective potential and mechanism in the middle cerebral artery occlusion (MCAO)-induced focal cerebral I/R model in rats.
Section snippets
Materials and chemicals
The leaves of G. biloba L were purchased from Hebei Anguo Medicinal Materials Market, China, and identified by Dr. Weiqi Zhong at Northeast Agricultural University. Sephadex G-200 and DEAE-52 cellulose were from Pharmacia (Sweden). Standard dextran was from Sigma. All other reagents were of the highest available quality in China.
Isolation and purification of polysaccharide GBPw
The dried leaves (700 g) of G. biloba were soaked with 95% EtOH for 6 h to remove lipids and pigment, followed by filtration. The residue was dried in air and then
Isolation and characterization of GBPw
The water-soluble crude polysaccharides (CGBP) with a yield of 10.85% (w/w) of starting material were obtained from the leaves of G. biloba by defatting with ethanol, hot water extraction, ethanol precipitation, deprotein by Sevag method, dialysis against water and drying in freeze dryer. Then CGBP was subjected to a DEAE–cellulose chromatography and eluted with distilled water, followed by 0.1, 0.2, 0.4 and 1.0 M NaCl at a flow rate of 1.0 mL/min. A 0.2 mL sample from each collected fraction (8
Conclusions
The MCAO model established by thread insertion is by far the most commonly used stroke model, the pathophysiology presented in which closely matches that in stroke patients suffered from focal cerebral arterial thrombosis (Longa et al., 1989). Using this model, pretreatment with GBPw was found to provide significant protection against the neuronal damage induced by cerebral I/R in rats. Our results showed clearly that a significant dose-dependent reduction of infracted volume, one most vigorous
Acknowledgement
We gratefully acknowledge the excellent technical assistance from Dr. Qilin Zhong at Northeast Agricultural University.
References (43)
A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein dye binding
Analytical Chemistry
(1976)- et al.
Cognitive and behavioral assessment in experimental stroke research: Will it prove useful?
Neuroscience and Biobehavioral Reviews
(2001) - et al.
Measurement of uronic acids without interference from neutral sugars
Analytical Biochemistry
(1991) - et al.
Protective effect of Danhong injection on cerebral ischemia—reperfusion injury in rats
Journal of Ethnopharmacology
(2012) - et al.
Neuroprotective effects of Ginkgo biloba constituents
European Journal of Pharmaceutical Sciences
(1995) - et al.
Inhibitory effect of MCI-186, a free radical scavenger, on cerebral ischemia following rat middle cerebral artery occlusion
General Pharmacology
(1998) - et al.
Comparative vasodilating actions among terpenoids and flavonoids contained in Ginkgo biloba extract
Clinica Chimica Acta
(2004) - et al.
Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction
Analytical Biochemistry
(1979) - et al.
A novel branched αβ-glucan isolated from the basidiocarps of the edible mushroom Pleurotus florida
Carbohydrate Polymers
(2008) - et al.
Cerebralcare Granule®, a Chinese herb compound preparation, improves cerebral microcirculatory disorder and hippocampal CA1 neuron injury in gerbils after ischemia—reperfusion
Journal of Ethnopharmacology
(2010)
Structure of an exocellular polysaccharide of Lactobacillus helveticus TN-4, aspontaneous mutant strain of Lactobacillus helveticus TY1-2
Carbohydrate Research
Neuroprotective effects of Ginkgo biloba extract
Cellular and Molecular Life Sciences
Reperfusion injury: Demonstration of brain damage produced by reperfusion after transient focal ischemia in rats
Journal of Cerebral Blood Flow and Metabolism
Reperfusion increases neutrophils and leukotriene B4 receptor binding in rat focal ischemia
Stroke
Apparent hydroxyl radical production by peroxynitrite: Implications for endothelial injury from nitric oxide and superoxide
Proceedings of the National Academy of Sciences of the United States of America
Evaluation of 2,3,5-triphenyltetrazolium chloride as a stain for detection and quantification of experimental cerebral infarction in rats
Stroke
Gingko biloba extract (EGb 761) prevents ischemic brain injury by activation of the Akt signaling pathway
The American Journal of Chinese Medicine
High-performance liquid chromatographic determination of selected flavonols in Ginkgo biloba solid oral dosage forms
Journal of Pharmaceutical Sciences
Colorimetric method for determination of sugars and related substances
Analytical Chemistry
Free radicals in brain metabolism and pathology
British Medical Bulletin
The cytosolic antioxidant copper/zinc-superoxide dismutase prevents the early release of mitochondrial cytochrome c in ischemic brain after transient focal cerebral ischemia in mice
The Journal of Neuroscience
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2021, Life SciencesCitation Excerpt :Currently, the primary treatment strategy for ischemic stroke is to restore blood supply as soon as possible through thrombolysis or mechanical hysterectomy. However, reperfusion of ischemic tissue is usually accompanied by oxidant stress, calcium overload, apoptosis and necrosis, which can aggravate brain micro-circulation disorders and destroy cell homeostasis, leading to neuronal death and brain damage [4–6]. Cerebral ischemia/reperfusion injury (CIRI), involves many complex pathological processes, including oxidative stress, inflammation and apoptosis.
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These authors contributed equally to this paper.