TrkA is essential components of the high-affinity NGF receptor necessary to mediate biological effects of the neurotrophins NGF. Here we report on the expression of trkA in the cerebral cortex and diencephalon of mongolian gerbils during postnatal development. The expression of trkA was identified by immunohistochemical method. In parietal cortex and piriform cortex, higher levels of trkA-IR (immunoreactivity) were detected at 3 days postnatal (P3) and at P9. Although trkA was not expressed till P3 in the parietal cortex, it was detectable at birth in the piriform cortex. Several regions, such as Layers I, IV & VI, did not show much expression. Layer I showed especially weak labeling. In the hippocampus, thalamus, and hypothalamus, higher levels of trkA-IR were detected at P6 and P12 than earlier days. But trkA was not expressed at birth in the hippocampus, at P3 in the reticular thalamic nucleus (Rt), or neonatally in the dorsomedial hypothalamic nucleus (DM). This data shows that expression of trkA is developmentally regulated and suggests that high affinity neurotrophin-receptors mediate a transient response to neurotrophines in the cerebral cortex and diencephalon during mongolian gerbil brain ontogeny.
Animals ; Animals, Newborn ; Cerebral Cortex/*metabolism ; Diencephalon/*metabolism ; Gerbillinae/*metabolism ; Immunohistochemistry/veterinary ; Nerve Growth Factor/metabolism ; Receptor, trkA/*metabolism

Aural cholesteatoma is characterized by invading squamous epithelia with altered growth properties. Cytokeratin (CK) expression is affected in epidermal proliferative diseases and represents the alterations of keratinocyte proliferation, differentiation, and migration. In the present study, the intensity of CK immuno-expression was determined, using densitometry at various sites in experimental cholesteatoma in order to characterize changes of keratinocytes. With cholesteatoma formation, CK4, a marker for non-keratinizing epithelia, increased in the suprabasal layers of the annular external auditory canal (EAC) and at the pars tensa indicating an altered differentiation and migration of keratinocytes. CK5/6, a marker of keratinizing squamous epithelium, increased only at the pars tensa of the tympanic membrane, indicating basal keratinocyte hyperplasia. CK1/10 increased in the suprabasal layer at the annular EAC, and at the peripheral pars tensa, indicating increased terminal differentiation of keratinocytes. CK13/16, markers of differentiation and hyperproliferation, increased in suprabasal layer of the EAC, and at the peripheral pars tensa. However, it decreased in the basal layer of the EAC, indicating hyperproliferation and migration of keratinocytes. The findings of this study support the basal cell hyperplasia hypotheses for the pathogenesis of aural cholesteatoma, with regard to hyperproliferation, migration, and an altered differentiation of keratinocytes.
Animals ; Biological Markers ; Cell Division ; Cell Movement ; Cholesteatoma, Middle Ear/*metabolism/*pathology ; Densitometry ; Gerbillinae ; Keratinocytes/metabolism/pathology ; Keratins/*biosynthesis

Peroxisome proliferator-activated receptor gamma (PPARgamma) has various actions including the regulation of adipocyte differentiation, lipid metabolism and glucose homeostasis. In the present study, we examined the changes of PPARgamma immunoreactivity and protein levels in the gerbil dentate gyrus (DG) after transient global cerebral ischemia using immunohistochemistry and western blot analysis. PPARgamma immunoreactivity was gradually increased from 1 day after ischemia-reperfusion. PPARgamma immunoreactivity, in accordance with protein level, was highest at 2 days after ischemia-reperfusion and was detected in microglia at this time. Thereafter, both PPARgamma immunoreactivity and protein level were decreased with time in the ischemic DG. These results indicate that PPARgamma may be related to the ischemia-induced microglial activation and neuronal damage/death in the DG after transient global cerebral ischemia.
Adipocytes ; Blotting, Western ; Brain Ischemia* ; Dentate Gyrus* ; Gerbillinae* ; Glucose ; Homeostasis ; Immunohistochemistry ; Lipid Metabolism ; Microglia ; Neurons ; PPAR gamma*

Peroxisome proliferator-activated receptor gamma (PPARgamma) has various actions including the regulation of adipocyte differentiation, lipid metabolism and glucose homeostasis. In the present study, we examined the changes of PPARgamma immunoreactivity and protein levels in the gerbil dentate gyrus (DG) after transient global cerebral ischemia using immunohistochemistry and western blot analysis. PPARgamma immunoreactivity was gradually increased from 1 day after ischemia-reperfusion. PPARgamma immunoreactivity, in accordance with protein level, was highest at 2 days after ischemia-reperfusion and was detected in microglia at this time. Thereafter, both PPARgamma immunoreactivity and protein level were decreased with time in the ischemic DG. These results indicate that PPARgamma may be related to the ischemia-induced microglial activation and neuronal damage/death in the DG after transient global cerebral ischemia.
Adipocytes ; Blotting, Western ; Brain Ischemia* ; Dentate Gyrus* ; Gerbillinae* ; Glucose ; Homeostasis ; Immunohistochemistry ; Lipid Metabolism ; Microglia ; Neurons ; PPAR gamma*

BACKGROUNDWater dropwort (Oenanthe javanica) as a popular traditional medicine in Asia shows various biological properties including antioxidant activity. In this study, we firstly examined the neuroprotective effect of Oenanthe javanica extract (OJE) in the hippocampal cornus ammonis 1 region (CA1 region) of the gerbil subjected to transient cerebral ischemia.

METHODSGerbils were established by the occlusion of common carotid arteries for 5 min. The neuroprotective effect of OJE was estimated by cresyl violet staining. In addition, 4 antioxidants (copper, zinc superoxide dismutase [SOD], manganese SOD, catalase, and glutathione peroxidase) immunoreactivities were investigated by immunohistochemistry.

RESULTSPyramidal neurons in the CA1 region showed neuronal death at 5 days postischemia; at this point in time, all antioxidants immunoreactivities disappeared in CA1 pyramidal neurons and showed in many nonpyramidal cells. Treatment with 200 mg/kg, not 100 mg/kg, OJE protected CA1 pyramidal neurons from ischemic damage. In addition, 200 mg/kg OJE treatment increased or maintained antioxidants immunoreactivities. Especially, among the antioxidants, glutathione peroxidase immunoreactivity was effectively increased in the CA1 pyramidal neurons of the OJE-treated sham-operated and ischemia-operated groups.

CONCLUSIONOur present results indicate that treatment with OJE can protect neurons from transient ischemic damage and that the neuroprotective effect may be closely associated with increased or maintained intracellular antioxidant enzymes by OJE.

Animals ; Antioxidants ; metabolism ; therapeutic use ; Gerbillinae ; Glutathione Peroxidase ; metabolism ; Hippocampus ; drug effects ; metabolism ; Ischemic Attack, Transient ; prevention & control ; Male ; Oenanthe ; chemistry ; Plant Extracts ; therapeutic use

OBJECTIVETo investigate the role of sodium cromoglycate in brain protection and its effects on brain tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) expressions after global cerebral ischemia-reperfusion (IR) injury in gerbils.

METHODSTwenty-four healthy male gerbils were randomized into 3 equal groups, namely the sham-operated group with isolation of the bilateral carotid arteries but without occlusion, IR injury model group with bilateral carotid artery occlusion, and sodium cromoglycate treatment group with bilateral carotid artery occlusion and sodium cromoglycate administration at 25 mg/kg via the lingual vein as soon as the reperfusion start with another dose 1 h later. The animals were then sacrificed and the thalamus were removed, fixed in 10% formaldehyde and sliced for observation under light microscope with HE staining. The rest brain tissues were prepared into homogenate to determine the content of TNF-alpha and IL-1beta. The right hemispheres of the gerbils were measured for wet weight and dry weight to calculate the water content in the brain.

RESULTSThe water content in the brain of the gerbils in the model group was the highest among the groups, and that in sodium cromoglycate treatment group was significantly less than that of the model group (P<0.05). Microscopic examination showed the most severe brain tissue damage in the model group with also the highest TNF-alpha and IL-1beta levels in the brain. The brain TNF-alpha and IL-1beta levels in sodium cromoglycate group were significantly decreased as compared with those in the model group (P<0.05).

CONCLUSIONSodium cromoglycate can alleviate brain IR injury possibly by lowering the TNF-alpha and IL-1beta levels in the brain tissues.

Animals ; Brain Ischemia ; metabolism ; Cromolyn Sodium ; pharmacology ; Gerbillinae ; Interleukin-1beta ; metabolism ; Male ; Neuroprotective Agents ; pharmacology ; Random Allocation ; Reperfusion Injury ; prevention & control ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVETo observe the protective effect of verapamil pretreatment against cerebral ischemia-reperfusion injury in gerbils.

METHODSThirty-three Mongolian gerbils were randomized into the control group (group A, n=6, with sham operation), ischemia group (group B), and 3 verapamil groups (groups C, D, and E, n=7) with intraperitpneal verapamil injection (2 mg/kg) 48, 24 and 12 h before ischemia, respectively. In group A, the bilateral common carotid arteries were only exposed without clamping, and in the other 4 groups, the arteries were clamped for 20 min followed by reperfusion for 50 min. The gerbils were then decapitated and the forebrain cerebral cortex was removed to determine superoxide dismutase (SOD) and glutathione (GSH) activities and measure the contents of malondial dehyde (MDA), endothelin (ET) and calcitonin gene-related peptide (CGRP). The left forebrain cerebral cortex was sampled in each group to observe the ultrastructural changes under electron microscope.

RESULTSIn groups C and D, SOD activities were significantly higher than those in group B (P<0.05), and in group E, the SOD activity elevation was not statistically significant (P>0.05). In groups C, D and E, GSH activity was significantly higher than that in group B (P<0.05). MDA content was significantly lower in groups C and D than in group B (P<0.05), but comparable between groups E and B (P>0.05). ET content was also significantly lower in the pretreatment groups (P<0.05), but CGRP content higher (not statistically so, however) than those in group B. The more serious ultrastructural damage of the cerebral tissue was observed in group B, but only mild damage was found in the verapamil groups.

CONCLUSIONSVerapamil given 12-48 h before cerebral ischemia may protect the gerbils from cerebral ischemia-reperfusion injury by enhancing SOD, GSH activities and decreasing ET content.

Animals ; Brain ; drug effects ; metabolism ; pathology ; Brain Ischemia ; complications ; metabolism ; pathology ; prevention & control ; Endothelins ; metabolism ; Gerbillinae ; Glutathione ; metabolism ; Malondialdehyde ; metabolism ; Receptors, Calcitonin Gene-Related Peptide ; metabolism ; Reperfusion Injury ; complications ; metabolism ; pathology ; prevention & control ; Superoxide Dismutase ; metabolism ; Verapamil ; pharmacology

OBJECTIVETo examine the effects of procaine and lidocaine on intracellular Ca(2+) release from sarcoplasmic reticulum ryanodine-sensitive Ca(2+) stores.

METHODSThe experiment was performed on hippocampal slices from 60-80 g male Mongolian gerbils. Levels of intracellular Ca(2+) concentration in the slices were measured by microfluorometry. The slices were perfused with 50 mmol/L KCl containing medium for 30 seconds. Then, the medium was switched to physiological medium. After 5 min of incubation, the slice was perfused with 20 mmol/L caffeine containing physiology medium for 2 min. Following incubation, the slice was superfused with physiological medium until the end of the experiment. The effects of procaine and lidocanin (100 micro mol/L) on caffeine-evoked Ca(2+) release were evaluated by adding them to the medium after high K(+) medium perfusion.

RESULTSCaffeine induced a marked increase in intracellular Ca(2+) concentration which was then decreased 12% upon the addition of procaine (P < 0.05); however, lidocaine, did not induce a similar inhibitory reaction.

CONCLUSIONProcaine inhibits ryanodine-receptor mediated Ca(2+) release from intracellular Ca(2+) stores, while lidocaine may inhibit Ca(2+) release through other mechanisms.

Anesthetics, Local ; pharmacology ; Animals ; Calcium ; metabolism ; Gerbillinae ; Hippocampus ; drug effects ; metabolism ; Lidocaine ; pharmacology ; Male ; Procaine ; pharmacology ; Ryanodine ; pharmacology ; Ryanodine Receptor Calcium Release Channel ; physiology

BACKGROUNDDanshen (Radix Salvia miltiorrhizae) has been used as a traditional medicine in Asia for treatment of various microcirculatory disturbance related diseases. Tanshinones are mainly hydrophobic active components, which have been isolated from Danshen and show various biological functions. In this study, we observed the neuroprotective effect of tanshinone I (TsI) against ischemic damage in the gerbil hippocampal CA1 region (CA1) after transient cerebral ischemia and examined its neuroprotective mechanism.

METHODSThe gerbils were divided into vehicle-treated-sham-group, vehicle-treated-ischemia-group, TsI-treated-sham-group, and TsI-treated-ischemia-group. TsI was administrated intraperitoneally three times (once a day for three days) before ischemia-reperfusion. The neuroprotective effect of TsI was examined using H&E staining, neuronal nuclei (NeuN) immunohistochemistry and Fluoro-Jade B staining. To investigate the neuroprotective mechanism of TsI after ischemia-reperfusion, immunohistochemical (IHC) and Western blotting analyses for Cu, Zn-superoxide dismutase (SOD1), Mn-superoxide dismutase (SOD2), brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-I (IGF-I) were performed.

RESULTSTreatment with TsI protected pyramidal neurons from ischemia-induced neuronal death in the CA1 after ischemia-reperfusion. In addition, treatment with TsI maintained the levels of SOD1 and SOD2 as determined by IHC and Western blotting in the CA1 after ischemia-reperfusion compared with the vehicle-ischemia-group. In addition, treatment with TsI increased the levels of BDNF and IGF-I determined by IHC and Western blotting in the TsI-treated-sham-group compared with the vehicle-treated-sham-group, and their levels were maintained in the stratum pyramidale of the ischemic CA1 in the TsI-treated-ischemia-group.

CONCLUSIONTreatment with TsI protects pyramidal neurons of the CA1 from ischemic damage induced by transient cerebral ischemia via the maintenance of antioxidants and the increase of neurotrophic factors.

Animals ; Antioxidants ; metabolism ; Blotting, Western ; Brain Ischemia ; drug therapy ; metabolism ; Brain-Derived Neurotrophic Factor ; metabolism ; Diterpenes, Abietane ; therapeutic use ; Gerbillinae ; Hippocampus ; metabolism ; Immunohistochemistry ; Insulin-Like Growth Factor I ; metabolism ; Male ; Nerve Growth Factors ; metabolism ; Superoxide Dismutase ; metabolism ; Superoxide Dismutase-1

The distribution of the nerve growth factor (NGF), the glial fibrillary acidic protein (GFAP) and the ciliary neurotrohic factor (CNTF) was performed in coronal sections of the mesencephalon, rhombencephalon and spinal cord in the developing Mongolian gerbils. Generally, NGF specifically recognizes neurons with the NGF receptor, whereas GFAP does the glia, and CNTF does the motor neurons. The receptor expression was examined separately in gerbils between embryonic days 15 (E15) and postnatal weeks 3 (PNW 3). The NGF-IR was first observed in the spinal cord at E21, which might be related to the maturation. The GFAP reactivity was peaked at the postnatal days 2 (PND2), while the highest CNTF-reaction was expressed at PNW 2. The GFAP stains were observed in the aqueduct and the spinal cord, which appeared to project laterally at E19. The CNTF was observed only after the birth and found in both the neurons and neuroglia of the substantia nigra, mesencephalon, cerebellum and the spinal cord from PND1 to PNW3. These results suggest that NGF, GFAP and CNTF are important for the development of the neurons and the neuroglia in the central nervous system at the late prenatal and postnatal stages.
Animals ; Brain Stem/enzymology/*metabolism ; Ciliary Neurotrophic Factor/*metabolism ; Embryonic and Fetal Development/physiology ; Female ; Gerbillinae/*embryology ; Glial Fibrillary Acidic Protein/*metabolism ; Immunohistochemistry/veterinary ; Mesencephalon/embryology/metabolism ; Nerve Growth Factor/*metabolism ; Pregnancy ; Rhombencephalon/embryology/metabolism ; Spinal Cord/embryology/*metabolism