Antioxidant-like protein 1 is altered in non-pyramidal cells and expressed in astrocytes in the gerbil hippocampal CA1 region after transient forebrain ischemia

Neurons in the hippocampal CA1 region, but not the dentate gyrus, are susceptible to oxidative stress in rats with streptozotocin-induced type 1 diabetes

In this study, we investigated the effects of streptozotocin-induced type 1 diabetes on antioxidant-like protein-1 immunoreactivity, protein carbonyl levels, and malondialdehyde formation, a marker for lipid peroxidation, in the hippocampus. For this study, streptozotocin (75 mg/kg) was intraperitoneally injected into adult rats to induce type 1 diabetes. The three experimental parameters were determined at 2, 3, 4 weeks after streptozotocin treatment. Fasting blood glucose levels significantly increased by 20.7–21.9 mM after streptozotocin treatment. The number of antioxidant-like protein-1 immunoreactive neurons significantly decreased in the hippocampal CA1 region, but not the dentate gyrus, 3 weeks after streptozotocin treatment compared to the control group. Malondialdehyde and protein carbonyl levels, which are modified by oxidative stress, significantly increased with a peak at 3 weeks after malondialdehyde treatment, and then decreased 4 weeks after malondialdehyde treatment. These results suggest that neurons in the hippocampal CA1 region, but not the dentate gyrus, are susceptible to oxidative stress 3 weeks after malondialdehyde treatment.

Difference of fibroblast growth factor receptor 1 expression among CA1-3 regions of the gerbil hippocampus after transient cerebral ischemia

Fibroblast growth factors are important regulators of neuronal development. In this study, we observed fibroblast growth factor receptor 1 (FGFR1) immunoreactivity and its protein levels in the hippocampus proper (CA1-3 regions) of the gerbil at various time points after ischemia/reperfusion. In the sham-operated group, FGFR1 immunoreaction was not detected in the hippocampus proper. FGFR1 immunoreaction was first detected in non-pyramidal neurons in the CA1-3 region at 12h and 1day after ischemia/reperfusion. From 2days after ischemia/reperfusion, FGFR1 immunoreaction was found in astrocytes, not in microglial cells, in the CA1 region: FGFR1 immunoreactivity and the number of astrocytes were significantly increased at 5days post-ischemia. Western blot analysis revealed that FGFR1 protein levels were also increased from 1day after ischemia/reperfusion. These results indicate that increase of FGFR1 in astrocytes of the ischemic CA1 region may be associated with gliosis followed by delayed neuronal death.

Immunohistochemical approach to the pathogenesis of clinical cases of bovine Herpesvirus type 5 infections

Meningoencephalitis by Herpesvirus type 5 (BoHV-5) in cattle has some features that are similar to those of herpetic encephalitis in humans and other animal species. Human Herpesvirus 3 (commonly known as Varicella-zoster virus 1), herpes simplex viruses (HSV), and equid Herpesvirus 1 (EHV-1) induce an intense inflammatory, vascular and cellular response. In spite of the many reports describing the histological lesions associated with natural and experimental infections, the immunopathological mechanisms for the development of neurological disorder have not been established. A total of twenty calf brains were selected from the Veterinary School, University of São Paulo State, Araçatuba, Brazil, after confirmation of BoHV-5 infection by virus isolation as well as by a molecular approach. The first part of the study characterized the microscopic lesions associated with the brain areas in the central nervous system (CNS) that tested positive in a viral US9 gene hybridization assay. The frontal cortex (Fc), parietal cortex (Pc), thalamus (T) and mesencephalon (M) were studied. Secondly, distinct pathogenesis mechanisms that take place in acute cases were investigated by an immunohistochemistry assay. This study found the frontal cortex to be the main region where intense oxidative stress phenomena (AOP-1) and synaptic protein expression (SNAP-25) were closely related to inflammatory cuffs, satellitosis and gliosis, which represent the most frequently observed neurological lesions. Moreover, MMP-9 expression was shown to be localized in the leptomeninges, in the parenchyma and around mononuclear infiltrates (p < 0.0001). These data open a new perspective in understanding the role of the AOP-1, MMP-9 and SNAP-25 proteins in mediating BoHV-5 pathogenesis and the strategies of host-virus interaction in order to invade the CNS.

Transient ischemia-induced changes of interleukin-2 and its receptor β immunoreactivity and levels in the gerbil hippocampal CA1 region

Interlukin-2 (IL-2) is an important cytokine in the brain: IL-2 and its receptors are involved with inflammatory processes. Chronological changes in IL-2 level in serum, and IL-2 and its receptor (IL-2 receptor beta, IL-2Rbeta) immunoreactivities and levels were examined in the hippocampal CA1 region after transient forebrain ischemia in gerbils. IL-2 level in serum significantly decreased 12 h after ischemia/reperfusion. IL-2 immunoreactivity was detected in the somata of pyramidal cells in sham-operated group. At 15 min after ischemia, IL-2 immunoreactivity was shown in non-pyramidal cells as well as pyramidal cells. One day after ischemia, IL-2 immunoreactivity was lowest, and IL-2 immunoreactivity is shown in non-pyramidal cells from 2 days after ischemia. Four days after ischemia, IL-2 immunoreactivity was shown in dying pyramidal cells. IL-2Rbeta immunoreactivity in the sham-operated and 15 min-3 min post-ischemic groups is detected in the cell membrane of pyramidal cells. From 3 h after ischemia, IL-2Rbeta immunoreactivity is found in cytoplasm and nuclei, but not in cell membrane. IL-2Rbeta immunoreactivity decreases from 6 h after ischemia and is shown mainly in non-pyramidal cells from 3 days after ischemia. The data of Western blot analyses for IL-2 and IL-2Rbeta was similar to the immunohistochemical data. IL-2 infusion into cerebrospinal fluid did not protect hippocampal neurons from ischemic damage. These results suggest that IL-2 and IL-2Rbeta show malfunction from 3 h after ischemia, and exogenous IL-2 does not protect ischemic neuronal damage.