Behavioural and neurochemical alterations following acute inflammation induced by intraperitoneal and intratracheal injection with lipopolysaccharide in mice.

The persistent symptoms of anxiety, depression, and fatigue that follow severe acute respiratory syndrome coronavirus 2 infection and accompany pulmonary inflammation pose significant clinical challenges. However, the correlation between pulmonary inflammation and mental health remains unclear. This study sought to examine the effects of intratracheal injection of lipopolysaccharide (LPS), a bacterial endotoxin, on anxiety-like behaviour in a mouse model suffering with pulmonary inflammation. The reactions of these animal models to new environments were evaluated using light-dark box and hole-board tests as anxiety-inducing stimuli. Microglial responses were evaluated via immunohistochemistry, and serum concentrations of tumour necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) were measured. Both intraperitoneal and intratracheal injections of LPS induced anxiety-like behaviours, as indicated by the outcomes of the light-dark box and hole-board tests. Serum levels of TNF-α and IL-6 considerably increased following both injection routes. The protein levels of the 5-HT2A and 5-HT1A receptors, which are crucial for neuropsychological function, in the frontal cortex and hippocampus of mice remained unchanged following LPS injections. Notably, hippocampal levels of brain-derived neurotrophic factor (BDNF) remarkably decreased following LPS injections. In the lungs, the administration of LPS via the intratracheal route led to a significant rise in the number of white blood cells present in the bronchoalveolar lavage fluid compared to the intraperitoneal injection method. These findings suggest that inflammation induced by intratracheal LPS injection may lead to anxiety-like behaviours in mice, potentially involving mechanisms related to hippocampal BDNF expression, which contributes to anxiety after pulmonary inflammation.

Visualization of Modified Bisarylbutadiyne-Tagged Small Molecules in Live-Cell Nuclei by Stimulated Raman Scattering Microscopy.

Visualizing the distribution of small-molecule drugs in living cells is an important strategy for developing specific, effective, and minimally toxic drugs. As an alternative to fluorescence imaging using bulky fluorophores or cell fixation, stimulated Raman scattering (SRS) imaging combined with bisarylbutadiyne (BADY) tagging enables the observation of small molecules closer to their native intracellular state. However, there is evidence that the physicochemical properties of BADY-tagged analogues of small-molecule drugs differ significantly from those of their parent drugs, potentially affecting their intracellular distribution. Herein, we developed a modified BADY to reduce deviations in physicochemical properties (in particular, lipophilicity and membrane permeability) between tagged and parent drugs, while maintaining high Raman activity in live-cell SRS imaging. We highlight the practical application of this approach by revealing the nuclear distribution of a modified BADY-tagged analogue of JQ1, a bromodomain and extra-terminal motif inhibitor with applications in targeted cancer therapy, in living HeLa cells. The modified BADY, methoxypyridazyl pyrimidyl butadiyne (MPDY), revealed intranuclear JQ1, while BADY-tagged JQ1 did not show a clear nuclear signal. We anticipate that the present approach combining MPDY tagging with live-cell SRS imaging provides important insight into the behavior of intracellular drugs and represents a promising avenue for improving drug development.

Neurogenesis impairment with glial activation in the hippocampus-connected regions of intracerebroventricular streptozotocin-injected mice.

Adult neurogenesis in the hippocampus and subventricular zone (SVZ) is impaired by intracerebroventricular administration of streptozotocin (icv-STZ) to rodents. Although neural cells in the several brain regions which connect with the hippocampus or SVZ is thought to be involved in the adult neurogenesis, few studies have investigated morphological alterations of glial cells in these areas. The present study revealed that icv-STZ induces reduction of neural progenitor cells and a dramatic increase in reactive astrocytes and microglia especially in the hippocampus and various hippocampus-connected brain areas. In contrast, there was no significant neuronal damage excluding demyelination of the stria medullaris. The results indicate the hippocampal neurogenesis impairment of this model might be occurred by activated glial cells in the hippocampus, or hippocampus-connected regions.

Phosphorylated SARM1 is involved in the pathological process of rotenone-induced neurodegeneration.

Sterile alpha and Toll/interleukin receptor motif-containing protein 1 (SARM1) is a NAD+ hydrolase that plays a key role in axonal degeneration and neuronal cell death. We reported that c-Jun N-terminal kinase (JNK) activates SARM1 through phosphorylation at Ser-548. The importance of SARM1 phosphorylation in the pathological process of Parkinson's disease (PD) has not been determined. We thus conducted the present study by using rotenone (an inducer of PD-like pathology) and neurons derived from induced pluripotent stem cells (iPSCs) from healthy donors and a patient with familial PD PARK2 (FPD2). The results showed that compared to the healthy neurons, FPD2 neurons were more vulnerable to rotenone-induced stress and had higher levels of SARM1 phosphorylation. Similar cellular events were obtained when we used PARK2-knockdown neurons derived from healthy donor iPSCs. These events in both types of PD-model neurons were suppressed in neurons treated with JNK inhibitors, Ca2+-signal inhibitors, or by a SARM1-knockdown procedure. The degenerative events were enhanced in neurons overexpressing wild-type SARM1 and conversely suppressed in neurons overexpressing the SARM1-S548A mutant. We also detected elevated SARM1 phosphorylation in the midbrain of PD-model mice. The results indicate that phosphorylated SARM1 plays an important role in the pathological process of rotenone-induced neurodegeneration.

Deuterium- and Alkyne-Based Bioorthogonal Raman Probes for In Situ Quantitative Metabolic Imaging of Lipids within Plants.

Plants can rapidly respond to different stresses by activating multiple signaling and defense pathways. The ability to directly visualize and quantify these pathways in real time using bioorthogonal probes would have practical applications, including characterizing plant responses to both abiotic and biotic stress. Fluorescence-based labels are widely used for tagging of small biomolecules but are relatively bulky and with potential effects on their endogenous localization and metabolism. This work describes the use of deuterium- and alkyne-derived fatty acid Raman probes to visualize and track the real-time response of plants to abiotic stress within the roots. Relative quantification of the respective signals could be used to track their localization and overall real-time responses in their fatty acid pools due to drought and heat stress without labor-intensive isolation procedures. Their overall usability and low toxicity suggest that Raman probes have great untapped potential in the field of plant bioengineering.

Three-Dimensional Analysis of Water Dynamics in Human Skin by Stimulated Raman Scattering.

The stratum corneum (SC), the outermost layer of the skin, has an important function to provide a barrier against dry environments. To evaluate the barrier function and the skin condition, it is crucial to investigate the ability of SC to absorb and retain water. In this study, we demonstrate stimulated Raman scattering (SRS) imaging of three-dimensional SC structure and water distribution when water is absorbed into dried SC sheets. Our results show that the process of water absorption and retention is dependent on the specific sample and can be spatially heterogeneous. We also found that acetone treatment leads to spatially homogeneous retention of water. These results suggest the great potential of SRS imaging in diagnosing skin conditions.

Multifunctional Metallothioneins as a Target for Neuroprotection in Parkinson's Disease.

Parkinson's disease (PD) is characterized by motor symptoms based on a loss of nigrostriatal dopaminergic neurons and by non-motor symptoms which precede motor symptoms. Neurodegeneration accompanied by an accumulation of α-synuclein is thought to propagate from the enteric nervous system to the central nervous system. The pathogenesis in sporadic PD remains unknown. However, many reports indicate various etiological factors, such as oxidative stress, inflammation, α-synuclein toxicity and mitochondrial impairment, drive neurodegeneration. Exposure to heavy metals contributes to these etiopathogenesis and increases the risk of developing PD. Metallothioneins (MTs) are cysteine-rich metal-binding proteins; MTs chelate metals and inhibit metal-induced oxidative stress, inflammation and mitochondrial dysfunction. In addition, MTs possess antioxidative properties by scavenging free radicals and exert anti-inflammatory effects by suppression of microglial activation. Furthermore, MTs recently received attention as a potential target for attenuating metal-induced α-synuclein aggregation. In this article, we summarize MTs expression in the central and enteric nervous system, and review protective functions of MTs against etiopathogenesis in PD. We also discuss neuroprotective strategies for the prevention of central dopaminergic and enteric neurodegeneration by targeting MTs. This review highlights multifunctional MTs as a target for the development of disease-modifying drugs for PD.

Central and Enteric Neuroprotective Effects by Eucommia ulmoides Extracts on Neurodegeneration in Rotenone-induced Parkinsonian Mouse.

Parkinson's disease (PD) is a progressive neurodegenerative disease of both the central and peripheral / enteric nervous systems. Oxidative stress and neuroinflammation are associated with the pathogenesis of PD, suggesting that anti-oxidative and anti-inflammatory compounds could be neuroprotective agents for PD. Eucommia ulmoides (EU) is a traditional herbal medicine which exerts neuroprotective effects by anti-inflammatory and anti-oxidative properties. Our previous study showed that treatment with chlorogenic acid, a component of EU, protected against neurodegeneration in the central and enteric nervous systems in a PD model. In this study, we examined the effects of EU extract (EUE) administration on dopaminergic neurodegeneration, glial response and α-synuclein expression in the substantia nigra pars compacta (SNpc), and intestinal enteric neurodegeneration in low-dose rotenone-induced PD model mice. Daily oral administration of EUE ameliorated dopaminergic neurodegeneration and α-synuclein accumulation in the SNpc. EUE treatment inhibited rotenone-induced decreases in the number of total astrocytes and in those expressing the antioxidant molecule metallothionein. EUE also prevented rotenone-induced microglial activation. Furthermore, EUE treatment exerted protective effects against intestinal neuronal loss in the PD model. These results suggest that EU exerts neuroprotective effects in the central and enteric nervous systems of rotenone-induced parkinsonism mice, in part by glial modification.

Probing Methionine Uptake in Live Cells by Deuterium Labeling and Stimulated Raman Scattering.

The small biomolecule methionine (Met) is a fundamental amino acid required for a vast range of biological processes such as protein synthesis, cancer metabolism, and epigenetics. However, it is still difficult to visualize the subcellular distribution of small biomolecules including Met in a minimally invasive manner. Here, we demonstrate stimulated Raman scattering (SRS) imaging of cellular uptake of deuterated methionine (d8-Met) in live HeLa cells by way of comparison to the previously used alkyne-labeled Met analogue─homopropargylglycine (Hpg). We show that the solutions of d8-Met and Hpg have similar SRS signal intensities. Furthermore, by careful image analysis with background subtraction, we succeed in the SRS imaging of cellular uptake of d8-Met with a much greater signal intensity than Hpg, possibly reflecting the increased and minimally invasive uptake kinetics of d8-Met compared with Hpg. We anticipate that d8-Met and other deuterated biomolecules will be useful for investigating metabolic processes with subcellular resolution.

Glial Cells as Possible Targets of Neuroprotection through Neurotrophic and Antioxidative Molecules in the Central and Enteric Nervous Systems in Parkinson's Disease.

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide. The loss of nigrostriatal dopaminergic neurons produces its characteristic motor symptoms, but PD patients also have non-motor symptoms such as constipation and orthostatic hypotension. The pathological hallmark of PD is the presence of α-synuclein-containing Lewy bodies and neurites in the brain. However, the PD pathology is observed in not only the central nervous system (CNS) but also in parts of the peripheral nervous system such as the enteric nervous system (ENS). Since constipation is a typical prodromal non-motor symptom in PD, often preceding motor symptoms by 10-20 years, it has been hypothesized that PD pathology propagates from the ENS to the CNS via the vagal nerve. Discovery of pharmacological and other methods to halt this progression of neurodegeneration in PD has the potential to improve millions of lives. Astrocytes protect neurons in the CNS by secretion of neurotrophic and antioxidative factors. Similarly, astrocyte-like enteric glial cells (EGCs) are known to secrete neuroprotective factors in the ENS. In this article, we summarize the neuroprotective function of astrocytes and EGCs and discuss therapeutic strategies for the prevention of neurodegeneration in PD targeting neurotrophic and antioxidative molecules in glial cells.

Influence of 5-HT2A receptor function on anxiety-like behavior induced by a combination treatment with doxorubicin and cyclophosphamide in rats.

Anxiety-like behavior induced by a combination of doxorubicin and cyclophosphamide may be mediated by serotonin (5-HT)2A receptor hyperactivity. The anxiolytic effects of fluoxetine may be inhibited by this combination. The present study examined the mechanisms underlying anxiety-like behavior induced by the combination doxorubicin and cyclophosphamide in rats. Anxiety-like behavior was induced during a light-dark test by the doxorubicin and cyclophosphamide treatment (once a week for 2 weeks). 5-HT2A receptor and 5-HT2A receptor-mediated extracellular signal-related kinase (ERK)1/2 levels were measured using Western blotting. 5-HT reuptake activity in fluoxetine-treated rats was also examined using microdialysis. ( ±)-1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane, a 5-HT2A receptor agonist, induced anxiety-like behavior. The fluoxetine treatment increased extracellular 5-HT concentrations in the hippocampus of vehicle- and doxorubicin and cyclophosphamide-treated rats. 5-HT transporter levels in the hippocampus were not affected by chemotherapy. The doxorubicin and cyclophosphamide treatment did not alter 5-HT2A receptor levels in the frontal cortex. However, chemotherapy increased 5-HT2A receptor-mediated ERK1/2 phosphorylation levels significantly more than the vehicle treatment. The present results suggest that anxiety-like behavior induced by the combination of doxorubicin and cyclophosphamide is mediated by 5-HT2A receptor hyperactivity without an increase in 5-HT2A receptor levels in rats.

Neuroprotective Effects of Anti-high Mobility Group Box-1 Monoclonal Antibody Against Methamphetamine-Induced Dopaminergic Neurotoxicity.

High mobility group box-1 (HMGB1) is a ubiquitous non-histone nuclear protein that plays a key role as a transcriptional activator, with its extracellular release provoking inflammation. Inflammatory responses are essential in methamphetamine (METH)-induced acute dopaminergic neurotoxicity. In the present study, we examined the effects of neutralizing anti-HMGB1 monoclonal antibody (mAb) on METH-induced dopaminergic neurotoxicity in mice. BALB/c mice received a single intravenous administration of anti-HMGB1 mAb prior to intraperitoneal injections of METH (4 mg/kg × 2, at 2-h intervals). METH injections induced hyperthermia, an increase in plasma HMGB1 concentration, degeneration of dopaminergic nerve terminals, accumulation of microglia, and extracellular release of neuronal HMGB1 in the striatum. These METH-induced changes were significantly inhibited by intravenous administration of anti-HMGB1 mAb. In contrast, blood-brain barrier disruption occurred by METH injections was not suppressed. Our findings demonstrated the neuroprotective effects of anti-HMGB1 mAb against METH-induced dopaminergic neurotoxicity, suggesting that HMGB1 could play an initially important role in METH toxicity.

Glutathione and Related Molecules in Parkinsonism.

Glutathione (GSH) is the most abundant intrinsic antioxidant in the central nervous system, and its substrate cysteine readily becomes the oxidized dimeric cystine. Since neurons lack a cystine transport system, neuronal GSH synthesis depends on cystine uptake via the cystine/glutamate exchange transporter (xCT), GSH synthesis, and release in/from surrounding astrocytes. Transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), a detoxifying master transcription factor, is expressed mainly in astrocytes and activates the gene expression of various phase II drug-metabolizing enzymes or antioxidants including GSH-related molecules and metallothionein by binding to the antioxidant response element (ARE) of these genes. Accumulating evidence has shown the involvement of dysfunction of antioxidative molecules including GSH and its related molecules in the pathogenesis of Parkinson's disease (PD) or parkinsonian models. Furthermore, we found several agents targeting GSH synthesis in the astrocytes that protect nigrostriatal dopaminergic neuronal loss in PD models. In this article, the neuroprotective effects of supplementation and enhancement of GSH and its related molecules in PD pathology are reviewed, along with introducing new experimental findings, especially targeting of the xCT-GSH synthetic system and Nrf2-ARE pathway in astrocytes.

Lactoferrin-like Immunoreactivity in Distinct Neuronal Populations in the Mouse Central Nervous System.

Lactoferrin (Lf) is an iron-binding glycoprotein mainly found in exocrine secretions and the secondary granules of neutrophils. In the central nervous system (CNS), expression of the Lf protein has been reported in the lesions of some neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, as well as in the aged brain. Lf is primarily considered an iron chelator, protecting cells from potentially toxic iron or iron-requiring microorganisms. Other biological functions of Lf include immunomodulation and transcriptional regulation. However, the roles of Lf in the CNS have yet to be fully clarified. In this study, we raised an antiserum against mouse Lf and investigated the immunohistochemical localization of Lf-like immunoreactivity (Lf-LI) throughout the CNS of adult mice. Lf-LI was found in some neuronal populations throughout the CNS. Intense labeling was found in neurons in the olfactory systems, hypothalamic nuclei, entorhinal cortex, and a variety of brainstem nuclei. This study provides detailed information on the Lf-LI distribution in the CNS, and the findings should promote further understanding of both the physiological and pathological significance of Lf in the CNS.

[Therapeutic strategy for Parkinson's disease: targeting zinc-binding protein in astrocytes].

Parkinson's disease (PD) is a progressive neurodegenerative disease with motor symptoms, such as tremor, akinesia/bradykinesia, rigidity and postural instability due to a loss of nigrostriatal dopaminergic neurons; PD patients also exhibit non-motor symptoms, such as hyposmia, orthostatic hypotension and constipation, which precede motor symptoms. Pathologically, Lewy bodies and neurites, which contains α-synuclein, are observed in the central and peripheral nervous system. To date, it is hypothesized that PD pathology appears first in the olfactory bulb and the enteric nervous system, and propagates progressively through the substantia nigra to finally reach the cerebral cortex. Major medications at present are nosotropic treatments to improve motor dysfunction in PD. Therefore, development of disease-modifying drug is required to slow or prevent PD progression. Astrocytes are known to play an important role in the maintenance of the neuronal environment and exert neuroprotective effects by production of antioxidants and neurotrophic factors and clearing toxic molecules. In the previous study, we demonstrated that astrocytes produced antioxidative molecules metallothionein (MT)-1/2 in response to oxidative stress and protected dopaminergic neurons against oxidative stress. MTs are cysteine-rich proteins possessing antioxidative properties. MTs bind to metals such as zinc (Zn) and copper (Cu) and function in metal homeostasis and detoxification; MTs regulate Zn-mediated transcriptional activation of various genes. Recently, it is reported that MTs prevent Cu-induced aggregation of α-synuclein. In this article, we review a new therapeutic strategy of neuroprotection in PD by targeting MTs in astrocytes.

[Anti-oxidants in astrocytes as target of neuroprotection for Parkinson's disease].

Recently, it has been reported that dysfunction of astrocytes is involved vulnerability of neuronal cells in several neurological disorders. Glutathione (GSH) is the most abundant intrinsic antioxidant in the central nervous system, and its substrate cysteine is readily becomes the oxidized dimeric cystine. Since neurons lack a cystine transport system, neuronal GSH synthesis depends on cystine uptake via the cystine/glutamate exchange transporter (xCT), GSH synthesis and release in/from surrounding astrocytes. The expression and release of the zinc-binding protein metallothionein (MT) in astrocytes, which is a strong antioxidant, is induced and exerts neuroprotective in the case of dopaminergic neuronal damage. In addition, the transcription factor Nrf2 induces expression of MT-1 and GSH related molecules. We previously revealed that several antiepileptic drugs, serotonin 5-HT1A receptor agonists, plant-derived chemicals (phytochemicals) increased xCT expression, Nrf2 activation, GSH or MT expression and release in/from astrocytes, and exerted a neuroprotective effect against dopaminergic neurodegeneration in Parkinson's disease model. Our serial studies on neuroprotection via antioxidant defense mechanism of astrocytes have found three target molecular systems of astrocytes for neuroprotection: (1) xCT-GSH synthetic system, (2) Nrf2 system and (3) 5-HT1A receptor-Nrf2-MT system, 5-HT1A-S100ß system. In this article, possible neuroprotective strategy for Parkinson's disease has been reviewed targeting antioxidative molecules in astrocytes.

N-Acetylcysteine Attenuates the Anxiety-Like Behavior and Spatial Cognition Impairment Induced by Doxorubicin and Cyclophosphamide Combination Treatment in Rats.

BACKGROUND: Cancer patients can suffer from psychological and cognitive disorders after chemotherapy, which influence quality of life. OBJECTIVE: Oxidative stress may contribute to the psychological and cognitive disorders induced in rats by chemotherapy. In the present study, we examined the effects of N-acetylcysteine, an anti-oxidant, on anxiety-like behavior and cognitive impairment in rats treated with a combination of doxorubicin and cyclophosphamide. METHODS: Rats were intraperitoneally injected with doxorubicin and cyclophosphamide once a week for 2 weeks. The light-dark test and the novel location recognition test were used to assess anxiety-like behavior and spatial cognition, respectively. The rats' hippocampal levels of glutathione (GSH) and glutathione disulfide (GSSG) were measured using a GSSG/GSH quantification kit. RESULTS: Combined treatment with doxorubicin and cyclophosphamide produced anxiety-like behavior and cognitive impairment in rats. N-acetylcysteine reversed the anxiety-like behavior and inhibition of novel location recognition induced by the combination treatment. Furthermore, the combination of doxorubicin and cyclophosphamide significantly reduced the rats' hippocampal GSH/GSSG ratios. N-acetylcysteine reversed the reduction in the GSH/GSSG ratio seen in the doxorubicin and cyclophosphamide-treated rats. CONCLUSION: These results suggest that N-acetylcysteine inhibits doxorubicin and cyclophosphamide-induced anxiety-like behavior and cognitive impairment by reducing oxidative stress in the hippocampus.

Neuron-Astrocyte Interactions in Parkinson's Disease.

Parkinson's disease (PD) is the second most common neurodegenerative disease. PD patients exhibit motor symptoms such as akinesia/bradykinesia, tremor, rigidity, and postural instability due to a loss of nigrostriatal dopaminergic neurons. Although the pathogenesis in sporadic PD remains unknown, there is a consensus on the involvement of non-neuronal cells in the progression of PD pathology. Astrocytes are the most numerous glial cells in the central nervous system. Normally, astrocytes protect neurons by releasing neurotrophic factors, producing antioxidants, and disposing of neuronal waste products. However, in pathological situations, astrocytes are known to produce inflammatory cytokines. In addition, various studies have reported that astrocyte dysfunction also leads to neurodegeneration in PD. In this article, we summarize the interaction of astrocytes and dopaminergic neurons, review the pathogenic role of astrocytes in PD, and discuss therapeutic strategies for the prevention of dopaminergic neurodegeneration. This review highlights neuron-astrocyte interaction as a target for the development of disease-modifying drugs for PD in the future.

Mirtazapine exerts astrocyte-mediated dopaminergic neuroprotection.

Mirtazapine, a noradrenergic and specific serotonergic antidepressant (NaSSA), is known to activate serotonin (5-HT) 1A receptor. Our recent study demonstrated that stimulation of astrocytic 5-HT1A receptors promoted astrocyte proliferation and upregulated antioxidative property in astrocytes to protect dopaminergic neurons against oxidative stress. Here, we evaluated the neuroprotective effects of mirtazapine against dopaminergic neurodegeneration in models of Parkinson's disease (PD). Mirtazapine administration attenuated the loss of dopaminergic neurons in the substantia nigra and increased the expression of the antioxidative molecule metallothionein (MT) in the striatal astrocytes of 6-hydroxydopamine (6-OHDA)-injected parkinsonian mice via 5-HT1A receptors. Mirtazapine protected dopaminergic neurons against 6-OHDA-induced neurotoxicity in mesencephalic neuron and striatal astrocyte cocultures, but not in enriched neuronal cultures. Mirtazapine-treated neuron-conditioned medium (Mir-NCM) induced astrocyte proliferation and upregulated MT expression via 5-HT1A receptors on astrocytes. Furthermore, treatment with medium from Mir-NCM-treated astrocytes protected dopaminergic neurons against 6-OHDA neurotoxicity, and these effects were attenuated by treatment with a MT-1/2-specific antibody or 5-HT1A antagonist. Our study suggests that mirtazapine could be an effective disease-modifying drug for PD and highlights that astrocytic 5-HT1A receptors may be a novel target for the treatment of PD.

Cerebellar Blood Flow and Gene Expression in Crossed Cerebellar Diaschisis after Transient Middle Cerebral Artery Occlusion in Rats.

Crossed cerebellar diaschisis (CCD) is a state of hypoperfusion and hypometabolism in the contralesional cerebellar hemisphere caused by a supratentorial lesion, but its pathophysiology is not fully understood. We evaluated chronological changes in cerebellar blood flow (CbBF) and gene expressions in the cerebellum using a rat model of transient middle cerebral artery occlusion (MCAO). CbBF was analyzed at two and seven days after MCAO using single photon emission computed tomography (SPECT). DNA microarray analysis and western blotting of the cerebellar cortex were performed and apoptotic cells in the cerebellar cortex were stained. CbBF in the contralesional hemisphere was significantly decreased and this lateral imbalance recovered over one week. Gene set enrichment analysis revealed that a gene set for "oxidative phosphorylation" was significantly upregulated while fourteen other gene sets including "apoptosis", "hypoxia" and "reactive oxygen species" showed a tendency toward upregulation in the contralesional cerebellum. MCAO upregulated the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in the contralesional cerebellar cortex. The number of apoptotic cells increased in the molecular layer of the contralesional cerebellum. Focal cerebral ischemia in our rat MCAO model caused CCD along with enhanced expression of genes related to oxidative stress and apoptosis.