OBJECTIVETo observe the distribution of neuronal nitric oxide synthase (nNOS)-immunopositive neurons in rat corpus striatum and their ultrastructural features.

METHODSBrain tissue specimens were obtained from normal SD rats, in which nNOS-immunopositive neurons were visualized by ABC immunocytochemistry and observed under immunoelectron microscope with pre-embedding staining.

RESULTSUnder light microscope, nNOS-immunopositive neurons appeared brown with distinct profiles of the cell body and processes. These neurons, mostly medium-sized and small cells, were located mainly in the lateral region of the corpus striatum. Only a few immunopositive neurons were detected in the medial region of the corpus striatum. Immunohistochemistry and transmission electron microscopy identified the nNOS-immunopositive neurons as interneurons possessing large nuclei with small amount of cytoplasma. The immunopositive granules were visualized as black plaques, and the larger ones distributed mainly in the cell bodies, some with monolayer membrane encapsulation. The small granules did not have the encapsulation, scattering in perinuclear regions and under the cell membrane, but not in the cell body. The immunopositive granules were also found in the axons and dendrites, but not in the vesicles of the synapses. In addition, many immunopositive terminals were found close to the blood vessels.

CONCLUSIONSnNOS-immunopositive neurons in rat corpus striatum are mainly medium-sized and small cells as is typical of the interneurons. The immunopositive granules locate in the cytoplasma, axons and dendrites, and larger granules have membrane coating while small ones do not, possibly in relation to their functions.

Animals ; Corpus Striatum ; enzymology ; ultrastructure ; Immunohistochemistry ; Male ; Microscopy, Electron, Transmission ; Neurons ; enzymology ; ultrastructure ; Nitric Oxide Synthase Type I ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the changes of serum neuron specific enolase in rats with septic shock.

METHODSThe model of septic shock was set up by injection of lipopolysaccharide (LPS, from Escherichia coil O55: B5) at a dose of 25 mg/kg through femoral vein. Twenty male Wistar rats were randomly divided into 2 groups: normal control group (LPS was substituted by same volume of normal saline solution) and septic shock group. Six hours after the septic shock model formed, whole blood was taken for measuring the serum neuron specific enolase (NSE). The brains of the rats were taken for histopathological examination.

RESULTSThe serum NSE of septic shock group was significantly higher than that of control group [(10.0781 +/- 0.526) microg/L vs. (3.7188 +/- 0.602) microg/L, P < 0.05]. Neurons were severely damaged 6 hours after injection of LPS. Neuronal necrosis and the damage of blood-brain barrier were seen by light and electron microscope in septic shock group but not in the control group.

CONCLUSIONNSE in serum increased when septic encephalopathy occurred, which indicated that NSE might become a marker of neural damage in septic shock.

Animals ; Biomarkers ; blood ; Blood Pressure ; Blood-Brain Barrier ; ultrastructure ; Brain ; cytology ; pathology ; Cell Death ; Disease Models, Animal ; Male ; Microscopy, Electron ; Neurons ; pathology ; ultrastructure ; O Antigens ; toxicity ; Phosphopyruvate Hydratase ; blood ; Rats ; Rats, Inbred BB ; Shock, Septic ; blood ; enzymology ; pathology

Phospholipase C (PLC) and related enzymes in signal transduction system are closely linked to cellular damage in ischemic encephalopathy. This study was undertaken to elucidate the time sequential changes of PLC isoenzymes (beta and gamma) in vulnerable areas of hippocampus in global ischemia and infarcted area in focal infarction. Mongolian gerbils were used because of their susceptibility to ischemic encephalopathy and divided into the following groups: the bilateral ischemia with various reperfusion periods group, unilateral progressive ischemia group, and focal ischemia group induced by infusion of iron particles through the femoral artery. The changes of PLC isoenzymes were observed immunohistochemically and matched with morphological changes. In the global ischemia with reperfusion group, the changes were most significant in hippocampus. Sequential changes of neurons such as red neurons at an early stage progressed to pknotic neurons at a later stage were noted with typical delayed neuronal damage in the corns ammonis (CA) 1 subfield of hippocampus. Red neurons and pyknotic neurons as well as intracytoplasmic inclusion in 3 to 24 hours of reperfusion showed loss of PLC isoenzymes as well as tubulin. The changes of PLC expression were corresponding to the degeneration of neurons with no discernible time sequential changes in remaining neurons. In the unilateral hemispheric progressive ischemia group, ischemic damage was far more marked and extensive with no selective injury pattern according to time and location. At 1 day, there was diffuse vacuolization and necrosis of neuropil with a loss of neuron. Admixed surviving neurons and vacuolated neuropil showed increased reaction to anti-PLC antibodies, which could be either an evidence of protein synthesis responding to ischemic insult or an artifactual change. Focal ischemia group showed time sequential changes of blood vessels and white blood cells with necrosis of surrounding tissue. Degenerating hippocampal neurons in infarction also showed a strong positive reaction to anti-PLC antibody, which was most likely due to condensation of cytoplasm rather than increased synthesis. This study showed different changes of PLC expression in global ischemic encephalopathy with reperfusion, progressive ischemia, and focal infarction, which suggested different pathophysiologic mechanism between these conditions.
Animal ; Brain Ischemia/*metabolism/pathology ; Cerebral Infarction/metabolism/pathology ; Female ; Gene Expression ; Gerbillinae ; Hippocampus/*enzymology ; Immunoenzyme Techniques ; Isoenzymes/*biosynthesis ; Male ; Neurons/enzymology/ultrastructure ; Phospholipase C/*biosynthesis ; Support, Non-U.S. Gov't ; Time Factors

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