OBJECTIVEImmunosuppressant tacrolimus (FK506) has shown neuroprotective effects on hypoxic-ischemic brain damage (HIBD) in the adult animal model. This study investigated whether FK506 has a protection against HIBD in neonatal rats by examining growthjassociated protein-43 (GAP-43) expression in the hippocampus.

METHODSNinety-six seven-day-old Sprague-Dawley rats were randomly divided into three groups: sham-operation, HIBD and FK506 intervention group. HIBD was induced in the later two groups. The FK506 intervention group was intraperitoneally injected with FK506 immediately after HIBD, at a dosage of 1 mg/kg daily, for three days. The HIBD group was injected with normal saline. Immunohistochemical technical was applied to examine GAP-43 expression in the hippocampus 24 and 72 hrs and 7 and 14 days after HIBD.

RESULTSCompared with the HIBD group, hematoxylin-eosin staining showed attenuated neuronal necrosis in the FK506 intervention group. In the HIBD group, the expression of GAP-43 increased significantly 72 hrs, and 7 and 14 days after HIBD compared with that in the sham-operation group. The GAP-43 expression in the FK506 intervention group was significantly higher than that in the HIBD group 72 hrs and 7 days after HIBD.

CONCLUSIONSFK506 might have neuroprotective effects against HIBD in neonatal rats.

Animals ; Animals, Newborn ; GAP-43 Protein ; analysis ; Hippocampus ; chemistry ; drug effects ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; pathology ; Immunosuppressive Agents ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Tacrolimus ; pharmacology

OBJECTIVEPrevious research suggests that dexamethasone (Dex) pretreatment protects neonatal rats against hypoxic-ischemic brain damage (HIBD). Some of the pharmacological effects of baicalin (a traditional Chinese medicine extracted from Scutellaria baicalensis Georgi) are similar to Dex. This study was designed to explore the effect of baicalin on the neuronal apoptosis following HIBD in neonatal rats.

METHODSSix-day-old Sprague-Dawley rats were randomly assigned into Control (without HI), HIBD, Dex-pretreatment and post-treatment, Baicalin-pretreatment and -post-treatment groups. HIBD was induced by ligating the left common carotid artery, followed by exposure to hypoxia. In the pretreatment groups either baicalin (16 mg/kg) or Dex (0.1 mg/kg) was administered to the rats 24 hrs before HIBD; in the post-treatment groups baicalin or Dex was given 30 minutes after HIBD. The rat pups were sacrificed on postnatal day 10, and brain tissues were harvested. Brain water content was determined, morphological changes were observed under a light microscope, and neuronal apoptosis was measured by terminal deoxynucleotidyl transferase mediated dUTP biotin nick end labeling (TUNEL) staining.

RESULTSThe brain water content and the number of apoptotic cells were significantly higher in the HIBD group than those of the Control group (P < 0.05). Both baicalin and Dex pretreatment decreased the brain water content from 88.9 +/- 1.7 % (HIBD group) to 87.4 +/- 0.7% (baicalin) or 87.3 +/- 0.6% (Dex) (P < 0.05) and the number of apoptotic cells were reduced from 251 +/- 28 (HIBD group) to 102 +/- 47 (baicalin) or 75 +/- 26 (Dex) (P < 0.05). Baicalin and Dex post-treatment had no effects on the brain water content and the number of apoptotic cells. Loss and degeneration of neurons could be observed in the HIBD group. Baicalin and Dex pretreatment significantly alleviated neuronal injury, but post-treatment did not.

CONCLUSIONSPretreatment with baicalin, as with Dex, has a protective effect against HIBD in neonatal rats, but baicalin or Dex post-treatment do not reverse the neuronal injuries.

Animals ; Apoptosis ; drug effects ; Body Water ; metabolism ; Brain ; metabolism ; pathology ; Female ; Flavonoids ; therapeutic use ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; pathology ; In Situ Nick-End Labeling ; Male ; Neuroprotective Agents ; therapeutic use ; Rats ; Rats, Sprague-Dawley

This study was done to determine the neuroprotective effect of cycloheximide on neonatal hypoxic-ischemic brain injury. Seven day-old newborn rat pups were subjected to 90 min of 8% oxygen following a unilateral carotid artery ligation. The extent of cerebral infarction was evaluated at 1 and 4 week of recovery. Apoptosis was identified by performing terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining and flow cytometry with a combination of fluoresceinated annexin V and propidium iodide. Brain infarction area was significantly increased at 4 week compared to 1 week after hypoxia-ischemia in the control group. With cycloheximide treatment, the number of TUNEL positive cells in the ipsilateral cerebral cortex at 48 hr and peri-infarct area at 1 and 4 week of recovery was significantly reduced, both apoptotic and necrotic cells by flow cytometry 48 hr after the injury were significantly reduced, and the extent of cerebral infarction at 1 and 4 week of recovery was also significantly attenuated compared to the hypoxia-ischemia control group. In summary, our data suggest that apoptosis plays an important role in the development of delayed infarction, and inhibition of apoptosis with cycloheximide significantly reduces the ensuing cerebral infarction in a newborn rat pup model of cerebral hypoxia-ischemia.
Time Factors ; Rats, Sprague-Dawley ; Rats ; Propidium ; Neuroprotective Agents/*pharmacology ; In Situ Nick-End Labeling ; Hypoxia-Ischemia, Brain/*drug therapy/metabolism/pathology ; Cycloheximide/*pharmacology ; Brain Infarction/pathology/prevention & control ; Apoptosis/drug effects ; Annexin A5/metabolism ; Animals, Newborn ; Animals

OBJECTIVETo examine the expression of calreticulin (CRT) and the changes of intracellular free calcium and neuronal apoptosis in the cerebral cortex of neonatal rats with hypoxic-ischemic brain damage (HIBD), and to investigate the intervention effects of Shenfu injection.

METHODSSeven-day-old rats were randomly assigned to three groups: control, hypoxic-ischemia (HI) and Shenfu-treated. Each group (n=50) was subdivided into 5 groups sacrificed at 3, 6, 12, 24 and 72 hours. Rat models of HIBD were prepared according to the Rice's method. Rats in the control group only underwent the separation of right common carotidartery. Shenfu injection was administered by intraperitoneal injections right after HI insults and then once daily at a dosage of 10 mL/kg for 3 days in the Shenfu-treated group. The expression of CRT in the cerebral cortex was detected by RT-PCR and Western blot. The free calcium concentrations were determined under a fluorescent microscope. The apoptosis rate was measured by the flow cytometry.

RESULTSCompared with the control group, the expression levels of CRT in the HI and the Shenfu-treated groups were obviously up-regulated (P<0.05), and the expression levels of CRT in the Shenfu-treated group were notably higher than those in the HI group (P<0.05) at all time points. The concentrations of intracellular free calcium and the apoptosis rate of neurons in the cerebral cortex in the Shenfu-treated group were significantly reduced compared with those in the HI group (P<0.05), but increased significantly compared with those in the control group at all time points (P<0.05).

CONCLUSIONSShenfu injection may have neuroprotective effects against HIBD by up-regulation of CRT expression and relief of calcium overload.

Animals ; Animals, Newborn ; Apoptosis ; drug effects ; Calcium ; metabolism ; Calreticulin ; analysis ; Cerebral Cortex ; metabolism ; pathology ; Drugs, Chinese Herbal ; pharmacology ; Female ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; pathology ; Injections ; Male ; Neurons ; drug effects ; Rats, Sprague-Dawley

Animals ; Animals, Newborn ; Antioxidants ; administration & dosage ; pharmacology ; Apoptosis ; drug effects ; Brain ; drug effects ; pathology ; Disease Models, Animal ; Female ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; pathology ; Immunohistochemistry ; Male ; Melatonin ; administration & dosage ; pharmacology ; Neuroprotective Agents ; administration & dosage ; pharmacology ; Rats ; Rats, Sprague-Dawley

Animals ; Animals, Newborn ; Brain ; drug effects ; metabolism ; pathology ; Disease Models, Animal ; Excitatory Amino Acid Antagonists ; pharmacology ; therapeutic use ; Female ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; Ketamine ; pharmacology ; therapeutic use ; Male ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Treatment Outcome

Animals ; Animals, Newborn ; Apoptosis ; drug effects ; Cerebral Cortex ; drug effects ; metabolism ; pathology ; Female ; Hypoxia-Ischemia, Brain ; drug therapy ; Male ; Malondialdehyde ; metabolism ; Nitric Oxide Synthase ; metabolism ; Nitroso Compounds ; therapeutic use ; Rats ; Rats, Wistar

OBJECTIVEIt has been reported that neuronal apoptosis plays a critical role in pathology of hypoxic-ischemic encephalopathy (HIE). Cytochrome C (CytC) is an important apoptotic protease activating factor. Inosine might have a neuroprotective effect against cerebral ischemia reperfusion injury by inhibiting the neuronal apoptosis and the expression of CytC mRNA in adult rats. This study examined the effects of inosine on neuronal apoptosis and CytC mRNA expression following hypoxic-ischemic brain damage (HIBD) in order to investigate the neuroprotectivity of inosine against cerebral ischemia injury in neonatal rats and the possible mechanism.

METHODSA total of 140 healthy 7-day-old Sprague-Dawley rat pups were randomly assigned into Control (n=40), HIBD (n=50) and Inosine treatment groups (n=50). HIBD rat models were established by ligating the left common carotid artery, followed by 8% O2 hypoxia exposure for 2 hrs in the HIBD and Inosine treatment groups. The Control group was not subjected to hypoxia-ischemia (HI). The Inosine treatment and the HIBD groups were randomly divided into 5 sub-groups sacrificed at 6 and 12 hrs, and 1, 3 and 7 days post- HI (n=10 each). The Control group rats were sacrificed at the corresponding time points (n=8 each). Inosine was administered to the Inosine treatment group by intraperitoneal injection immediately after HIBD at the dosage of 100 mg/kg twice daily for 7 days. TUNEL staining and in situ hybridization method was used to detect neuronal apoptosis and CytC mRNA expression respectively.

RESULTSFew apoptotic cells and CytC mRNA positive cells were found in brain tissues of the Control group. In the HIBD group, the number of apoptotic cells and the CytC mRNA expression in the cortical and hippocampal gyrum CA1 areas increased 6 hrs after HI, peaking at 1 day after HI and then decreased gradually. Until the 7th day, the number of apoptotic cells and the CytC mRNA expression in the cortical and hippocampal gyrum CA1 areas in the HIBD group remained significantly higher than in the Control group. Inosine treatment decreased the apoptotic cells and the CytC mRNA expression in both areas from 6 hrs to 7 days after HI compared with the HIBD group. The linear correlation analysis demonstrated that the number of apoptotic cells was positively correlated to the CytC mRNA expression in neonatal rats with HIBD (r=0.88, P < 0.01) .

CONCLUSIONSInosine can reduce the number of apoptotic cells and down-regulate the expression of CytC mRNA following HIBD in neonatal rats. The decreased number of apoptotic cells was positively correlated to the decreased CytC mRNA expression after inosine treatment, suggesting that inosine offered neuroprotectivity against HIBD possibly through inhibiting the CytC mRNA expression and resulting in a decrease of cell apoptosis.

Animals ; Apoptosis ; drug effects ; Cytochromes c ; genetics ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; pathology ; In Situ Nick-End Labeling ; Inosine ; pharmacology ; therapeutic use ; Neurons ; drug effects ; Neuroprotective Agents ; pharmacology ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the effects of androgen on the expression of aromatase cytopigment P450 (AROM) and nerve growth factor (NGF) in the brain and brain ultrastructure in neonatal rats with hypoxic-ischemic brain damage (HIBD) in order to investigate the mechanism underlying the protective effect of androgen against HIBD.

METHODSNinety-six seven-day-old Sprague-Dawley rats were randomly divided into three groups: sham-operation, HIBD and androgen treatment (n=32 each). HIBD was induced by the ligation of left common carotid artery and hypoxia exposure. The rats in the androgen treatment and the HIBD groups were injected intraperitoneally with testosterone propionate (25 mg/kg) and arachis oil respectively immediately after hypoxia-ischemia (HI). After 24 and 72 hrs and 7 and 10 days of HI, AROM and NGF expression in the cortex and the hippocampus was detected with the immunohistochemical method. The ultrastructural changes of neurons in the cortex and the hippocampus were observed under a transmission electron microscope.

RESULTSNerve cells of the HIBD group showed obvious injuries including cell organ decreasing, cellularoedema, nuclear swelling, chromatic agglutination, mitochondria decreasing and swelling, as well as an increase in apoptotic cells. Compared with the HIBD group, the nerve cells in the androgen treatment group had integrated nuclear membrane, well-distributed chromatin and abundant cell organs, and less cell apoptosis and increased axon regeneration. There was a positive expression of NGF and AROM in the brain cortex and the hippocampus in the HIBD group 24 hrs after HI. The expression of NGF and AROM increased significantly 72 hrs after HI, peaked 7 days after HI and then began to decrease but remained at a higher level than that in the sham-operation group 10 days after HI. The NGF and AROM expression in the cortex and the hippocampus in the androgen treatment group was significantly higher than that in the sham-operation and the HIBD groups 72 hrs, and 7 and 10 days after HI.

CONCLUSIONSAndrogen treatment can promote axon regeneration and morphous recovery of neurons and decrease neural apoptosis in neonatal rats with HIBD. The neuroprotection of androgen is produced possibly through an increase in the expression of NGF and AROM in the brain.

Androgens ; therapeutic use ; Animals ; Animals, Newborn ; Aromatase ; analysis ; Brain ; enzymology ; Female ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; pathology ; Immunohistochemistry ; Male ; Nerve Growth Factor ; analysis ; Neurons ; ultrastructure ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate whether desferoxamine (DFO) preconditioning can induce tolerance against cerebral ischemia and its effect on the expression of hypoxia inducible factor 1alpha (HIF-1alpha) and erythropoietin (EPO) in vivo and in vitro.

METHODSRat model of cerebral ischemia was established by middle cerebral artery occlusion with or without DFO administration. Infarct size was examined by TTC staining, and the neurological severity score was evaluated according to published method. Cortical neurons were cultured under ischemia stress which was mimicked by oxygen-glucose deprivation (OGD), and the neuron damage was assessed by MTT assay. Immunofluorescent staining was employed to detect the expressions of HIF-1alpha and EPO.

RESULTSThe protective effect induced by DFO (decreasing the infarction volume and ameliorating the neurological function) appeared at 2 d after administration of DFO (post-DFO), lasted until 7 d and disappeared at 14 d (P < 0.05); the most effective action was observed at 3 d post-DFO. DFO induced tolerance of cultured neurons against OGD: neuronal viability was increased 23%, 34%, 40%, 48% and 56% at 8 h, 12 h, 24 h, 36 h, and 48 h, respectively, post-DFO (P < 0.05). Immunofluorescent staining found that HIF-1alpha and EPO were upregulated in the neurons of rat brain at 3 d and 7 d post-DFO; increase of HIF-1alpha and EPO appeared in cultured cortex neurons at 36 h and 48 h post-DFO.

CONCLUSIONDFO induced tolerance against focal cerebral ischemia in rats, and exerted protective effect on OGD cultured cortical neurons. DFO significant induced the expression of HIF-1alpha and EPO both in vivo and in vitro. DFO preconditioning can protect against cerebral ischemia, which may be associated with the synthesis of HIF-1alpha and EPO.

Animals ; Brain Ischemia ; drug therapy ; metabolism ; physiopathology ; Cells, Cultured ; Cerebral Infarction ; drug therapy ; metabolism ; physiopathology ; Deferoxamine ; pharmacology ; therapeutic use ; Disease Models, Animal ; Erythropoietin ; metabolism ; Fluorescent Antibody Technique ; Hypoxia-Inducible Factor 1, alpha Subunit ; drug effects ; metabolism ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; physiopathology ; Infarction, Middle Cerebral Artery ; drug therapy ; metabolism ; physiopathology ; Iron ; metabolism ; Ischemic Preconditioning ; methods ; Nerve Degeneration ; drug therapy ; metabolism ; physiopathology ; Neurons ; drug effects ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; Siderophores ; pharmacology ; therapeutic use ; Time Factors ; Treatment Outcome ; Up-Regulation ; drug effects ; physiology