Upregulation of Dpysl2 and Spna2 gene expression in the rat brain after ischemic stroke.

Ischemia activates the synthesis of potentially damaging and protective proteins in the central nervous system. Dihydropyrimidinase-like 2 (Dpysl2), a protein involved in neuronal differentiation and axonal guidance, and alpha-spectrin 2 (Spna2), a protein involved in maintaining neuronal membrane integrity, were found altered in various nervous system diseases. Modifications of Dpysl2 and Spna2 proteins have been reported in focal ischemic stroke, but their significance is not yet established. Therefore, this study was aimed to investigate the temporal expression of Dpysl2 and Spna2 genes in normal and stroke rat brain and to characterize stroke brains for cell areas, apoptosis, and microglia cells. The middle cerebral artery of rat brain was occluded and the brain tissue was sectioned for in situ hybridization of Dpysl2 and Spna2 genes, TUNEL, and OX-42 immunofluorescence staining. Dpysl2 and Spna2 mRNA expression was quantified by real-time RT-PCR. Characterization of stroke brain for apoptosis and microglia cells showed apoptotic cells and activated microglia, mainly in the infarct core of ipsilateral cortex and striatum of stroke brain. Significant upregulation of Dpysl2 and Spna2 mRNA expression in the penumbra region after stroke was observed predominantly in injured swollen cells in the cortex and striatum. Upregulation of Dpysl2 and Spna2 expression in hypertrophic cells in the penumbra regions of cortex and striatum of stroke brain indicates an early neuronal defense mechanism involving active neuronal repair, regeneration and development, as these genes are known to be involved in neurite outgrowth and plasticity.

Combinatorial-approached neuroprotection using pan-caspase inhibitor and poly (ADP-ribose) polymerase (PARP) inhibitor following experimental stroke in rats; is there additional benefit?

Energy requiring apoptosis and presumably unregulated necrosis are considered conceptually and morphologically distinct forms of cell death which have been initially identified as two exclusive pathways. However, several apoptotic characteristics have been observed in the necrotic core lesion in ischemia which led to the controversial theory that cell death advances via a number of hybrid pathways among a continuum between the two processes. ATP availability has been shown to influence the decision between apoptosis and necrosis. The aims of our study are 1) to determine if combined inhibitors administration of pan-caspase inhibitor Carbobenzoxy-Val-Ala-Asp-fluoromethylketone (z-VAD-fmk) and non-selective poly (ADP-ribose) polymerase (PARP) inhibitor 3-aminobenzamide (3-AB) can further reduce infarct volume compared to single modality of either inhibitor following ischemic insult, 2) to ascertain the pharmacological intervention up to 24 hour post-middle cerebral artery occlusion (MCAo), and 3) to correlate intracellular ATP level with infarct volume. Single modality treatment was optimised at 3 mg/kg z-VAD-fmk and 30 mg/kg 3-AB with infarct volume measured at 24.13%+/-3.89% and 26.98%+/-2.22% respectively, while untreated control group was determined at 45.97%+/-1.86%. Combined inhibitors treatment rendered further reduction in infarct volume, measuring 7.228%+/-1.988%, 21.02%+/-1.06%, 24.40%+/-2.12% at 30 min, 6 h, 24 h post-ischemia respectively. In conclusion, the combined inhibitors administration of both z-VAD-fmk and 3-AB show further increased in infarct volume reduction with our ischemic model up to the 24 hour post-MCAo. However, in our in vivo study, no correlation between intracellular ATP level and infarct size was established.

Poly(adenosine diphosphate-ribose) polymerase expression in human traumatic brain injury.

OBJECT: This study was designed to elucidate the pattern of expression of poly(adenosine diphosphate-ribose) polymerase (PARP) in human pericontusional brain tissue and to correlate these findings with commonly used clinical parameters. METHODS: The expression of PARP was ascertained using immunohistochemical studies in eight specimens of human pericontusional brain tissue obtained when the patients underwent craniotomy for mass effect. The following demographic and clinical parameters were also analyzed for each patient: age, sex, postresuscitation Glasgow Coma Scale score (GCS), computerized tomography findings, intracranial pressure (ICP) recordings during the first 24 hours postsurgery, and the time interval from injury to surgery. The authors observed that PARP was present in neurons of pericontusional tissue and that it conformed to two patterns of subcellular localization; it was found either in the nucleus exclusively or in both nuclear and cytoplasmic compartments. They showed that a preponderance of cytoplasmic staining in neurons was significantly correlated with a short time interval from trauma to surgery (< or = 4 hours). There was no correlation, however, between the subcellular distribution of PARP and clinical parameters such as admission GCS score and ICP readings obtained intra- and postoperatively. CONCLUSIONS: As in earlier studies in which it has been suggested that caspase-cleaved PARP translocates to the cytoplasm during apoptosis, the authors' results indicate that apoptosis may predominate in the initial time frame after head injury. This information may well influence the timing of administration of antiapoptotic neuronal salvage agents for adjunctive therapy of head injury in the future.