[Neuroprotective mechanisms of the ubiquinol action in experimental focal ischemia]

Ischemic stroke is one of the most socially important diseases characterized by impaired cerebral circulation with focal damage of the brain tissue and decreased functionality. Despite the successes of modern pharmacology, possibilities of pharmacotherapy for stroke remain limited, and the research for new drugs with neuroprotective effects that can prevent brain cell death is still relevant. In this study we have investigated the neuroprotective activity of ubiquinol as a part of an innovative form on a rat model of irreversible 24 h-cerebral ischemia with evaluation of the mechanisms of its neuroprotective effect. Ubiquinol (30 mg/kg), administered intravenously in the acute period of irreversible 24 h focal cerebral ischemia, had a direct neuroprotective effect, characterized by a decrease in the volume of brain tissue necrosis. The protective effect of ubiquinol is due to its ability to inhibit the development of oxidative stress by the direct anti-radical action, preventing the increase in the lipid hydroperoxide content in the brain tissue adjacent to the focus of necrosis, lowering the lipid oxidation rate in plasma against under conditions of increased total antioxidant activity in the brain and blood of experimental animals. In vitro experiments have shown the ability of ubiquinol to prevent cell death in primary culture of cerebral neurons of rat brain under 4 h oxygen/glucose deprivation followed by 20 h reoxygenation.

Effect of Coenzyme Q10 on Expression of UbiAd1 Gene in Rat Model of Local Cerebral Ischemia

The study examined the effect of endogenous lipid-soluble antioxidant coenzyme Q10 on the expression of UbiA gene of prenyltransferase domain-containing protein 1 (UbiAd1) involved in synthesis of vitamin K2 (and probably of coenzyme Q10) on a rat model of ischemic stroke provoked by ligation of the middle cerebral artery in the left hemisphere. Ischemia enhanced expression of mRNA of UbiAd1 gene in both cerebral hemispheres, but the effect was significant only in the contralateral one. The study revealed no effect of intraperitoneal injection of coenzyme Q10 (30 mg/kg) on ischemia-produced elevation of mRNA of UbiAd1 gene. Further studies are needed to assess possible neuroprotective effects of antioxidant coenzyme Q10.

[Effects of ischemia on the expression of neurotrophins and their receptors in rat brain structures outside the lesion site, including on the opposite hemisphere]

Neurotrophins stimulate the regeneration of neural tissue after lesions. It is also known that the sources of neurogenesis and cerebral function recovery are predominantly located in subcortical brain structures. The effects of ischemia on the expression of genes that encode neurotrophins (Bdnf, Ngf, Nt-3) and their receptors (TrkB, TrkA, TrkC, p75) in brain structures outside the lesion site were studied 3, 24, and 72 h after irreversible unilateral occlusion of the middle cerebral artery in rats. Changes in the mRNA expression of these genes were assessed by relative quantification using real-time RT-PCR. Sham surgery was found to stimulate the expression of genes that encode neurotrophins (Bdnf, Ngf) and their receptor (p75). It has been shown that ischemia influenced the expression of neurotrophins (Bdnf, Ngf, Nt-3) and their receptors (TrkB, TrkA, TrkC, p75) in brain structures outside the lesion focus, including the contralateral hemisphere. The downregulation of Bdnf and TrkB transcripts and Ngf and TrkA upregulation in the contralateral cortex on the first day of ischemia obviously reflected stress response. On day 3, Nt-3 transcription increased in all investigated structures outside the lesion focus. In the contralateral hemisphere, relative levels of TrkA and TrkC mRNA expression increased, while p75 expression decreased. Presumably, the observed changes in gene transcription serve to facilitate neuroplasticity and neural tissue regeneration.

[Effect of tripeptide Pro-Gly-Pro on rat brain transcriptome in focal ischemia]

Biologically active regulatory peptide, tripeptide Pro-Gly-Pro (PGP) was used as C-terminal fragment for peptide drugs Semax and Selank. In recent years the independent effects of PGP were observed. The question was raised, whether PGP contributes to the effects ofpeptide drugs containing PGP as a fragment. The genome-wide analysis was performed to investigate the influence of PGP on the transcriptome of ischemic rat brain cortex tissues. The gene expression alterations caused by the action of the tripeptide PGP were compared with the gene expression of the control group "ischemia" at 3 and 24 h after permanent occlusion of left middle cerebral artery. The altered expression was detected for 29 genes at 3 h and 57--at 24 h. The proteins encoded by these genes have variety of functions: cytokines, transport proteins, transcription factors, transmembrane receptors, etc. Biological processes, which are related to the genes with altered expression, were distinguished. The influence of PGP on the diversity of biological processes in different systems of the organism is demonstrated for the first time. The process "Immune response" was the most statistically notable at 24 h after occlusion. The expression of the immune system genes was predominately down regulated.

Intravenous xenotransplantation of human placental mesenchymal stem cells to rats: comparative analysis of homing in rat brain in two models of experimental ischemic stroke

Mesenchymal stem cells from human placenta obtained after term natural delivery were cultured and labeled with vital dye Dil of magnetic fluorescing microparticles. The labeled cells were transplanted intravenously to rats with occlusion of the median cerebral artery. Penetration of cells through the brain-blood barrier and their distribution in the brain of experimental animals were studied on serial cryostat sections. Two models of cerebral artery occlusion associated with different traumatic consequences were used. The efficiency of crossing the blood-brain barrier by transplanted cells, the number of mesenchymal cells attaining the ischemic focus and neurogenic zones, and the time of death of transplanted cells largely depended on the degree and nature of injury to the central nervous system, which should be taken into account when planning the experiments for evaluation of the effects of cell therapy on the models of neurological diseases and in clinical studies in the field of regenerative neurology.

[Experimental hemorrhagic stroke: the study of neuropeptides (MIF, selank) in the intraperitoneal injection]

The aim of this study was to examine Taftsin derivates--macrophage inhibitory factor (MIF, Thr-Lys-Pro) and heptapeptide selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) in the model of experimental intracerebral hemorrhage in rats. The double autologous blood injection in the basal nucleus was used as a model of intracerebral hemorrhage. Animals ware randomly divided into three groups--the control group (n = 5) was treated with saline, the second group (n = 5) was injected with MIF in dose 150 mkg/ kg/day, the third group (n = 5) received Selank in dose 300 mkg/kg/day. Intraperitoneal injection of peptides was used. Body weight assessment, neurological examination and brain MRI were performed in 24, 72 hours and 10 days after the hematoma formation. The effect of neuropeptides on the functional restoration in animals, in the absence of the effect on hematoma volume and perifocal edema, was found. The significant reduction of perifocal edema and hematoma volume was observed in the 10th day after the hematoma formation in all experimental groups (p < 0.05). Only the control group of animals showed the significant (p < 0.05) weight loss in the 3rd day after the operation. The rate of neurological deficit was different: the significant improvement assessed with Menzes and limb placing test scales was seen only in the groups treated with neuropeptides in the 10th day.

Use of bone marrow mesenchymal (stromal) stem cells in experimental ischemic stroke in rats

The effects of human mesenchymal stem cells on neurological functions and behavioral reactions of animals and on damaged brain tissue were studied on the model of focal cerebral ischemia in rats. Homing and differentiation of transplanted mesenchymal stem cells were also studied. Significant regression of neurological disorders after cell transplantation was noted, no appreciable shifts were detected by magnetic resonance tomography. Homing of transplanted cells was detected mainly in the zone of focal ischemia. Some cells died, others exhibited signs of differentiation into neurons and glia.

[Evidence for the neuroprotective properties of afobazole in experimental model of focal brain ischemia]

The neuroprotective effect of the new selective anxiolytic afobazole was evaluated in rats with ischemic stroke produced by the occlusion of the left middle cerebral artery, with simultaneous ligation of the ipsilateral carotid artery. Afobazole exhibits a protective effect in a dose range from 0.1 to 5.0 mg/kg for the first injection delayed 24 h after operation and double daily injections over the following two days.

Protective effect of phenyl-t-butylnitrone in rats with focal cerebral ischemia

Phenyl-t-butylnitrone produces a potent neuroprotective effect in rats with focal cerebral ischemia modeled by distal occlusion of the middle cerebral artery. The infarction area markedly decreased after treatment with phenyl-t-butylnitrone. The content of phenyl-t-butylnitrone in the brain, liver, and kidneys was measured by the method of electron paramagnetic resonance.

[Effect of phenyl-tert-butylnitrone, mexidol and nooglutil on the ischemic lesion zone and memory in rats following middle cerebral artery occlusion]

An ischemic cerebral affection zone amounting to 22.51 +/- 3.0% of the ipsilateral hemisphere volume was found on the frontal brain sections in the frontoparietal cortex of rats 72 h after occlusion of the distal branch of the medial cerebral artery. The new nootropic drug nooglutyl [N-(5-hydroxynicotinoyl)-L-glutamic acid] in a dose of 10 mg/kg, as well as mexidol or phenyl-tert-butylnitrone (PBN) in a dose of 100 mg/kg, introduced into the vein at the moment of occlusion and intraperitoneally for two days after operation, effectively restricted the affected zone: nooglutyl, up to 7.6 +/- 2.28%; mexidol, up to 9.55 +/- 1.9%; and PBN, up to 12.8 +/- 1.7% of the ipsilateral hemisphere volume. On the third day after operation, animals preliminarily learnt to the passive avoidance conditioned reflex exhibited violated memory retrieval. The retrieval was significantly improved in the test animals treated with mexidol and especially nooglutyl.