Neuroprotective effects of water-soluble Ganoderma lucidum polysaccharides on cerebral ischemic injury in rats.
OBJECTIVE
To investigate the neuroprotective effects of water-soluble Ganoderma lucidum polysaccharides (GLPS) on cerebral ischemic injury in rats, and to explore the involved mechanisms.


METHODS
Two models [middle cerebral artery occlusion (MCAO) in Sprague-Dawley (SD) rats and oxygen and glucose deprivation (OGD) in primary cultured rat cortical neurons] were employed to mimic ischemia-reperfusion (I/R) damage, in vivo and in vitro, respectively. Cerebral infarct area was measured by tetrazolium staining, and neurological functional deficits were assessed at 24h after I/R. Neuronal apoptosis was studied by Nissl staining and DNA fragmentation assay. Neuronal injury was assessed by morphological examination using phase-contrast microscopy and quantified by measuring the amount of lactate dehydrogenase (LDH) leakage, cell viability was measured by sodium 3'-1- (phenylaminocarbonyl)-3, 4-tetrazolium-bis (4-methoxy-6-nitro) benzene sulfonic acid (XTT) reduction. Neuronal apoptosis was determined by flow cytometry, and electron microscopy was used to study morphological changes of neurons. Caspase-3, -8 and -9 activation and Bcl-2, Bax protein expression were determined by western blot analysis.


RESULTS
Oral administration of GLPS (100, 200 and 400mg/kg) significantly reduced cerebral infarct area, attenuated neurological functional deficits, and reduced neuronal apoptosis in ischemic cortex. In OGD model, GLSP (0.1, 1 and 10 microg/ml) effectively reduced neuronal cell death and relieved cell injury. Moreover, GLPS decreased the percentage of apoptotic neurons, relieved neuronal morphological damage, suppressed overexpression of active caspases-3, -8 and -9 and Bax, and inhibited the reduction of Bcl-2 expression.


CONCLUSIONS
Our findings indicate that GLPS protects against cerebral ischemic injury by inhibiting apoptosis by downregulating caspase-3 activation and modulating the Bcl-2/Bax ratio.
Zhou
Zi-Yi
ZY
Laboratory of Neurology, Institute of Integrative Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
Tang
Yu-Ping
YP
Xiang
Jun
J
Wua
Pin
P
Jin
Hui-Ming
HM
Wang
Zhong
Z
Mori
Masao
M
Cai
Ding-Fang
DF
D000818:Animals; D002545:Brain Ischemia / Q000473:pathology / Q000517:prevention & control*; D002478:Cells, Cultured; D005638:Fruit; D008297:Male; D018696:Neuroprotective Agents / Q000302:isolation & purification / Q000627:therapeutic use*; D010936:Plant Extracts / Q000302:isolation & purification / Q000627:therapeutic use*; D011134:Polysaccharides / Q000302:isolation & purification / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020940:Reishi; D012995:Solubility; D014867:Water
D018696:Neuroprotective Agents; D010936:Plant Extracts; D011134:Polysaccharides; D014867:Water