The protective effect of fish n-3 fatty acids on cerebral ischemia in rat prefrontal cortex

The protective efficacy of vitamin E and cod liver oil against cisplatin-induced acute kidney injury in rats

Cisplatin (CP) is a highly effective chemotherapeutic agent against neoplasms, but its clinical utility is limited due to the side effects of its dose-dependent nephrotoxicity. Vitamin E (Vit E) and cod liver oil (CLO) are natural substances with chemoprotective effects. The present study was conducted to evaluate the protective effects of Vit E and/or CLO for CP-induced acute kidney injury (AKI) in rats. This study involved 40 mature male Wistar albino rats that were equally allocated into eight groups: Veh, Vit E, CLO, Vit E + CLO, CP, Vit E + CP, CLO + CP, and Vit E + CLO + CP. The co-administration of Vit E and CLO significantly ameliorated CP-induced elevations in serum creatinine (Cr), blood urea nitrogen (BUN), interleukin 1 beta (IL-1β), and interleukin- 6 (IL-6). Further, rats that received Vit E and/or CLO showed significant decrease in malondialdehyde (MDA) and increases in superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels in renal tissues, compared to CP-intoxicated rats. Additionally, the treatment restored the normal histological architecture (except for few cast formations) and upregulated the immunostaining area% of aquaporin 3 (AQP3) and downregulated the immunostaining area% of Bcl2 associated X protein (BAX) and inducible nitric oxide synthase (iNOS). The observed effects were stronger in the combination treatment group. The obtained data revealed that Vit E and CLO co-administration protects against the CP-induced AKI more than monotherapy with Vit E or CLO.

Bradykinin and noradrenaline preconditioning influences level of antioxidant enzymes SOD, CuZn-SOD, Mn-SOD and catalase in the white matter of spinal cord in rabbits after ischemia/reperfusion

The aim of present work is to assess the effects of bradykinin (Br) or noradrenaline (Nor) preconditioning to the levels of antioxidant enzymes: superoxide dismutase (SOD), copper, zinc superoxide dismutase (CuZn-SOD), manganese superoxide dismutase (Mn-SOD) and catalase in ischemia/reperfusion (I/R) model in the rabbit spinal cord white matter as well as effect on glial fibrillary acidic protein (GFAP) and ubiquitin immunoreaction in glial cells. Rabbits were preconditioned by intraperitoneal single dose of Br or Nor 48 h prior to 20 min of ischemia followed by 24 or 48 h of reperfusion. White matter of L3-L6 spinal cord segments was used for comparison of antioxidant enzyme levels in sham control, ischemic groups and four preconditioned groups. The total SOD level in the Br or Nor preconditioned groups after 48 h of reperfusion was increased vs Br or Nor preconditioned groups after 24 h of reperfusion. The comparison among the ischemic group vs Br preconditioned (P<0.05), and Nor preconditioned (P<0.001) groups after 48 h of reperfusion, showed statistically significant decrease of Mn-SOD activity. Tissue catalase level activity was significantly decreased in the Br preconditioned group after 48 h of reperfusion (P<0.05) and Nor preconditioned groups after 24 h of reperfusion (P<0.001) and also after 48 h of reperfusion (P<0.001), in comparison to ischemic group after 48 h of reperfusion. Significantly decreased tissue catalase activity (P<0.05) in both Nor preconditioned groups after 24 or 48 h of reperfusion was measured vs Br preconditioned group after 48 h of reperfusion. According to our results, in the white matter, activation of stress proteins in glial cells, as well as antioxidant enzymes levels, were influenced by pharmacological preconditioning followed by 20 min of ischemia and 24 or 48 h of reperfusion. These changes contribute to ischemic tolerance acquisition and tissue protection from oxidative stress during reperfusion period.

Possible prophylactic effect of omega-3 fatty acids on cadmium-induced neurotoxicity in rats' brains

Cadmium (Cd) has long been noted to induce neurodegenerative disorders. Therefore, this study aimed to assess the toxicological impact of Cd on rat brains and evaluate the possible ameliorative impact of omega-3 fatty acids as a protective agent of nervous system. Rats were divided into four groups: group I supplemented orally with saline; group II intoxicated with CdCl₂ (5 mg/kg b.w. orally), and groups III and VI supplemented with omega-3 (100 mg/kg b.w. orally) simultaneously or before CdCl₂ administration, respectively. Cd intoxication induced biochemical and histopathological disturbances in treated rats. Omega-3 fatty acid considerably improved the Cd-associated biochemical changes, reduced the elevation of lipid peroxidation, and normalized the Cd impact on the levels of superoxide dismutase, catalase, glutathione-S-transferases, 8-hydroxydeoxyguanosine, heatshock protein70, nuclear factor-κB, and interferon-γ as well as of neuronal enzymes such as acetylecholinesterase and monoamine oxidase within the brains of treated rats. Additionally, histological findings supported the results that Cd treatment-induced neurodegenerative changes and that polyunsaturated fatty acids act as antioxidants and neuroprotective agents against Cd toxicity. Co-treatment with omega-3 fatty acid was more beneficial than pretreatment. Thus, omega-3 fatty acid should be included in diet to prevent or suppress neurodegenerative disorders caused by continuous exposure to Cd.

Omega-6 fatty acids down-regulate matrix metalloproteinase expression in a coronary heart disease-induced rat model

The present study investigated the therapeutic potential of omega-6 fatty acids, according to their effects on antioxidant markers and matrix metalloproteinases (MMPs), in coronary heart disease-induced rats. Rats were grouped into group I (sham control), group II (control), group III (0.5 g/kg bwt of omega-6 fatty acids) and group IV (1 g/kg bwt of omega-6 fatty acids). Reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), reduced glutathione (GSH), catalase, glutathione peroxidase (Gpx) and acetylcholinesterase (AChE) enzyme activities were determined. ROS and MDA were substantially reduced, whereas SOD, catalase, Gpx and AChE were significantly increased, following supplementation with omega-6 fatty acids. MMP-2 mRNA expression was drastically increased by 95% in group II. Treatment significantly reduced MMP-2 mRNA expression by 12.3% and 26.7% in groups III and IV respectively. MMP-9 mRNA expression drastically increased, by 121%, in group II. Treatment significantly reduced MMP-9 mRNA expression by 22.6% and 29.4% in groups III and IV respectively. MMP-2 protein expression was drastically increased, by 81%, in group II. Treatment significantly reduced MMP-2 protein expression by 9.4% and 26% in groups III and IV respectively. MMP-9 protein expression was drastically increased, by 100%, in group II. Treatment significantly reduced MMP-9 protein expression by 18.9% and 26.9% in groups III and IV respectively. In summary, the consumption of omega-6 fatty acids significantly decreased MDA and ROS, while SOD, catalase, GHS, Gpx and AChE were increased. Furthermore, omega-6 fatty acids significantly downregulated MMP-2 and MMP-9 expression in our coronary heart disease-induced rat model.

Protective effects of omega-3 fatty acids against Alzheimer's disease in rat brain endothelial cells

OBJECTIVES

Omega-3 fatty acids are well-known unsaturated fatty acids that are essential for growth and development in animals. They primarily participate in the development of intelligence, the nervous system, and vision, and the metabolism of neurotransmitters. Omega-3 fatty acids have been widely studied in the treatment of Alzheimer's disease (AD). Omega-3 fatty acids are known to have neuroprotective effects due to their antioxidant capacity. Rotenone has been shown to induce neurotoxicity in vitro.

METHODS

We investigated the protective effects of omega-3 fatty acids against AD in rat brain microvascular endothelial cells (RBMVECs) in vitro. Lipid peroxidation, reactive oxygen species (ROS), glutathione peroxidase (Gpx), reduced glutathione (GSH), superoxide dismutase (SOD), and catalase levels were evaluated in RBMVECs. Flow cytometry was performed to assess apoptosis.

RESULTS

Lipid peroxidation and ROS were reduced in RBMVECs following incubation with omega-3 fatty acids. Catalase, Gpx, and SOD were increased in RBMVECs following incubation with omega-3 fatty acids. Flow cytometry showed that incubation with omega-3 fatty acids reduced the amount of apoptotic RBMVECs.

CONCLUSION

Our results suggest that omega-3 fatty acids show potential as a therapeutic agent against AD.

Models and methods for conditioning the ischemic brain

BACKGROUND

In the last decades the need to find new neuroprotective targets has addressed the researchers to investigate the endogenous molecular mechanisms that brain activates when exposed to a conditioning stimulus. Indeed, conditioning is an adaptive biological process activated by those interventions able to confer resistance to a deleterious brain event through the exposure to a sub-threshold insult. Specifically, preconditioning and postconditioning are realized when the conditioning stimulus is applied before or after, respectively, the harmul ischemia.

AIMS AND RESULTS

The present review will describe the most common methods to induce brain conditioning, with particular regards to surgical, physical exercise, temperature-induced and pharmacological approaches. It has been well recognized that when the subliminal stimulus is delivered after the ischemic insult, the achieved neuroprotection is comparable to that observed in models of ischemic preconditioning. In addition, subjecting the brain to both preconditioning as well as postconditioning did not cause greater protection than each treatment alone.

CONCLUSIONS

The last decades have provided fascinating insights into the mechanisms and potential application of strategies to induce brain conditioning. Since the identification of intrinsic cell-survival pathways should provide more direct opportunities for translational neuroprotection trials, an accurate examination of the different models of preconditioning and postconditioning is mandatory before starting any new project.

DHA, EPA and their combination at various ratios differently modulated Aβ25-35-induced neurotoxicity in SH-SY5Y cells

Omega-3 polyunsaturated fatty acids (n-3 PUFAs), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), have been reported to prevent neurodegenerative diseases such as Alzheimer's disease (AD) in both experimental and clinical/epidemiological studies. However, whether DHA and EPA from natural products exert similar or different neuroprotective effects and how these n-3 PUFAs target cellular and molecular mechanisms associated with neurodegenerative disease pathogenesis are unknown. In the present study, we used amyloid-β (Aβ)_25-35-treated differentiated SH-SY5Y cells as a model of AD to compare the neuroprotective effect of DHA, EPA and their combination at various ratios. Administration of 20μM Aβ_25-35 significantly decreased SH-SY5Y cell viability, the expression of nerve growth factor (NGF), its TrkA receptor, and the level of glutathione (GSH) and increased reactive oxygen species (ROS), nitric oxide, tumor necrosis factor (TNF)-α, brain derived neurotrophic factor (BDNF) and its TrkB receptor. Aβ_25-35 also increased the Bax/Bcl-2 ratio and the expression of Caspase-3 in these cells. Compared with the Aβ group, pretreatment with DHA/EPA significantly reduced cell death, especially at ratio of 1:1 and 2:1 DHA/EPA or pure DHA. However, the most efficient ratio for reducing changes in ROS and GSH and for decreasing TNF-α appeared at ratio of 1:2 and 1:1, respectively. The ratio of 1:1, 2:1 and pure DHA resulted in significant increase in the level of NGF. Furthermore, pure DHA was the most efficient for reducing Bax/Bcl ratio and Caspase-3 expression. In conclusion, DHA, EPA and their combination differently modulated Aβ_25-35-induced neurotoxicity in SH-SY5Y cells by exerting anti-oxidative, anti-inflammatory and neurotrophic effects.

Protective effects of oil of Sardinella pilchardis against subacute chlorpyrifos-induced oxidative stress in female rats

This study was conducted to evaluate the protective effects of Sardinella pilchardis oil and vitamin E against chlorpyrifos- (CPF-) induced liver, kidney, and brain oxidative damage in female rats. The rats were divided into 6 experimental groups: the control group, the group treated with fish oil, the group that received fish oil for 2 weeks and CPF orally for 7 days, the group treated only with CPF, the group treated with vitamin E for 2 weeks and CPF for 7 days, and the group treated with vitamin E. Oral exposure to CPF induced a significant increase in serum biochemical parameters; hepatic, kidney, and brain LPO; and a decrease in superoxide dismutase, catalase, and glutathione peroxidase activities. Fish oil or vitamin E decreased significantly the mentioned biochemical parameters as compared to rats treated with CPF alone. This study suggests that fish oil has an ameliorative effect for the alleviation of the oxidative damage induced by CPF.

Effects of Nigella sativa Extract on Markers of Cerebral Angiogenesis after Global Ischemia of Brain in Rats

BACKGROUND

Reduction of permanent or transient cerebral blood flow may lead to some structural and functional changes of the brain, causing high mortality and morbidity. The aim of this experimental study was to investigate the effects of hydroalcoholic extract of Nigella sativa (NS) on markers of cerebral angiogenesis in rats induced by global brain ischemia.

METHODS

Thirty-two male Wistar rats (250 ± 20 g) were randomly divided into 4 groups: group 1, control group receiving only normal saline; group 2, sham group undergoing surgery and stroke induction without treatment; and groups 3 and 4 treated with 10 and 20 mg/kg NS, respectively, after induction of stroke. Global ischemia was induced by ligation of the right carotid artery for 20 minutes.

RESULTS

According to the results of this study, brain edema and infarct volume were significantly decreased in the group treated with 20 mg/kg NS compared with the group treated with 10 mg/kg NS (P < .05). Global ischemia caused a significant reduction in gene expression of vasoactive endothelial growth factor (VEGF) and hypoxia-inducible factor (HIF) in the sham group compared with the control group (P < .05), but NS groups, in led to a significant increase in gene expression of VEGF and HIF compared with the sham group (P < .05). In addition, the activity level of matrix metallopeptidase-9 was decreased among NS groups compared with the control group (P < .05).

CONCLUSIONS

Application of NS extract among rats with brain ischemia is associated with increase of VEGF and HIF as angiogenic markers and inhibition of matrix metallopeptidase-9 activities.

Neuroprotective diets for stroke

Stroke is one of the main causes of death and disability in the elderly. In the last few years, there has been increasing evidence that suggests the influence of the diet on the decrease of stroke risk. Probably, because of the presence of bioactive components with beneficial effects such as antioxidant or anti-inflammatory properties. This article reviews several dietary bioactive compounds from studies in models of cerebral ischemia that have obtained promising results decreasing cerebral damage. We propose that many of these compounds present in diet could be good candidates to test new neuroprotection approaches focused on reducing the damage and protecting the brain before stroke occurs.

A specific dietary intervention to restore brain structure and function after ischemic stroke

Occlusion of the middle cerebral artery (MCAo) is among the most common causes of ischemic stroke in humans. Cerebral ischemia leads to brain lesions existing of an irreversibly injured core and an ischemic boundary zone, the penumbra, containing damaged but potentially salvageable tissue. Using a transient occlusion (30 min) of the middle cerebral artery (tMCAo) mouse model in this cross-institutional study we investigated the neurorestorative efficacy of a dietary approach (Fortasyn) comprising docosahexaenoic acid, eicosapentaenoic acid, uridine, choline, phospholipids, folic acid, vitamins B12, B6, C, and E, and selenium as therapeutic approach to counteract neuroinflammation and impairments of cerebral (structural+functional) connectivity, cerebral blood flow (CBF), and motor function. Male adult C57BL/6j mice were subjected to right tMCAo using the intraluminal filament model. Following tMCAo, animals were either maintained on Control diet or switched to the multicomponent Fortasyn diet. At several time points after tMCAo, behavioral tests, and MRI and PET scanning were conducted to identify the impact of the multicomponent diet on the elicited neuroinflammatory response, loss of cerebral connectivity, and the resulting impairment of motor function after experimental stroke. Mice on the multicomponent diet showed decreased neuroinflammation, improved functional and structural connectivity, beneficial effect on CBF, and also improved motor function after tMCAo. Our present data show that this specific dietary intervention may have beneficial effects on structural and functional recovery and therefore therapeutic potential after ischemic stroke.

The Role of Omega-3 Polyunsaturated Fatty Acids in Stroke

Stroke is the third commonest cause of death following cardiovascular diseases and cancer. In particular, in recent years, the morbidity and mortality of stroke keep remarkable growing. However, stroke still captures people attention far less than cardiovascular diseases and cancer. Past studies have shown that oxidative stress and inflammation play crucial roles in the progress of cerebral injury induced by stroke. Evidence is accumulating that the dietary supplementation of fish oil exhibits beneficial effects on several diseases, such as cardiovascular diseases, metabolic diseases, and cancer. Omega-3 polyunsaturated fatty acids (n-3 PUFAs), the major component of fish oil, have been found against oxidative stress and inflammation in cardiovascular diseases. And the potential of n-3 PUFAs in stroke treatment is attracting more and more attention. In this review, we will review the effects of n-3 PUFAs on stroke and mainly focus on the antioxidant and anti-inflammatory effects of n-3 PUFAs.

Long Chain Omega-3 Polyunsaturated Fatty Acid Supplementation Alleviates Doxorubicin-Induced Depressive-Like Behaviors and Neurotoxicity in Rats: Involvement of Oxidative Stress and Neuroinflammation

Doxorubicin (DOX) is a chemotherapeutic agent widely used in human malignancies. Its long-term use can cause neurobiological side-effects associated with depression. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs), the essential fatty acids found in fish oil, possess neuroprotecitve and antidepressant activities. Thus, the aim of this study was to explore the potential protective effects of ω-3 PUFAs against DOX-induced behavioral changes and neurotoxicity. ω-3 PUFAs were given daily by gavage (1.5 g/kg) over three weeks starting seven days before DOX administration (2.5 mg/kg). Open-field test (OFT) and forced swimming test (FST) were conducted to assess exploratory activity and despair behavior, respectively. Our data showed that ω-3 PUFAs supplementation significantly mitigated the behavioral changes induced by DOX. ω-3 PUFAs pretreatment also alleviated the DOX-induced neural apoptosis. Meanwhile, ω-3 PUFAs treatment ameliorated DOX-induced oxidative stress in the prefrontal cortex and hippocampus. Additionally, gene expression of pro-inflammatory cytokines, including IL-1β, IL-6, and TNF-α, and the protein levels of NF-κB and iNOS were significantly increased in brain tissues of DOX-treated group, whereas ω-3 PUFAs supplementation significantly attenuated DOX-induced neuroinflammation. In conclusion, ω-3 PUFAs can effectively protect against DOX-induced depressive-like behaviors, and the mechanisms underlying the neuroprotective effect are potentially associated with its anti-oxidant, anti-inflammatory, and anti-apoptotic properties.

The Neuroprotective Effect of Syringic Acid on Spinal Cord Ischemia/Reperfusion Injury in Rats

Acute arterial occlusions via different vascular pathologies are the main causes of spinal cord ischemia. We investigated neuroprotective effects of syringic acid on spinal cord ischemia injury in rats. Rats were divided into four groups: (I) sham-operated control rats, (II) spinal cord ischemia group, (III) spinal cord ischemia group performed syringic acid, and (IV) spinal cord ischemia group performed methylprednisolone intraperitoneally. Spinal cord ischemia was performed by the infrarenal aorta cross-clamping model. The spinal cord was removed after the procedure. The biochemical and histopathological changes were observed within the samples. Functional assessment was performed for neurological deficit scores. A significant decrease was seen in malondialdehyde levels in group III as compared to group II (P < 0.05). Besides these, nuclear respiratory factor-1 and superoxide dismutase activity of group III were significantly higher than group II (P < 0.05). In histopathological samples, when group III was compared with group II, there was a significant decrease in numbers of apoptotic neurons (P < 0.05). In immunohistochemical staining, BECN1 and caspase-3-immunopositive neurons were significantly decreased in group III compared with group II (P < 0.05). The neurological deficit scores of group III were significantly higher than group II at twenty-fourth hour of ischemia (P < 0.05). Our study revealed that syringic acid pretreatment in spinal cord ischemia/reperfusion reduced oxidative stress and neuronal degeneration as a neuroprotective agent. Ultrastructural studies are required for syringic acid to be developed as a promising therapeutic agent to be utilized for human spinal cord ischemia in the future.

The Neuroprotective Effect of Kefir on Spinal Cord Ischemia/Reperfusion Injury in Rats

Objective

The main causes of spinal cord ischemia are a variety of vascular pathologies causing acute arterial occlusions. We investigated neuroprotective effects of kefir on spinal cord ischemia injury in rats.

Methods

Rats were divided into three groups : 1) sham operated control rats; 2) spinal cord ischemia group fed on a standard diet without kefir pretreatment; and 3) spinal cord ischemia group fed on a standard diet plus kefir. Spinal cord ischemia was performed by the infrarenal aorta cross-clamping model. The spinal cord was removed after the procedure. The biochemical and histopathological changes were observed within the samples. Functional assessment was performed for neurological deficit scores.

Results

The kefir group was compared with the ischemia group, a significant decrease in malondialdehyde levels was observed (p<0.05). Catalase and superoxide dismutase levels of the kefir group were significantly higher than ischemia group (p<0.05). In histopathological samples, the kefir group is compared with ischemia group, there was a significant decrease in numbers of dead and degenerated neurons (p<0.05). In immunohistochemical staining, hipoxia-inducible factor-1α and caspase 3 immunopositive neurons were significantly decreased in kefir group compared with ischemia group (p<0.05). The neurological deficit scores of kefir group were significantly higher than ischemia group at 24 h (p<0.05).

Conclusion

Our study revealed that kefir pretreatment in spinal cord ischemia/reperfusion reduced oxidative stress and neuronal degeneration as a neuroprotective agent. Ultrastructural studies are required in order for kefir to be developed as a promising therapeutic agent to be utilized for human spinal cord ischemia in the future.

The protective effect of caffeic acid on global cerebral ischemia-reperfusion injury in rats

Ischemic stroke is a major cause of death and disability all over the world. Ischemic stroke results from a temporary or permanent reduction of cerebral blood flow that leads to functional and structural damage in different brain regions. Despite decades of intense research, the beneficial treatment of stroke remains limited. In light of this, the search for effective means ameliorating cerebral ischemia-reperfusion injury (CIRI) is one of the major problems of experimental medicine and biology. Recently, the 5-Lipoxygenase (5-LO, a key enzyme metabolizing arachidonic acid to produce leukotrienes) inhibitors have been showed to protect brain against ischemic damage in animal model of cerebral ischemia. Caffeic acid, an inhibitor of 5-LO, is a phenolic compound widely distributed in medicinal plants. The aim of this study was to investigate the effect of caffeic acid on global cerebral ischemia-reperfusion injury in rats. The study was carried out on 45 rats that were randomly divided into five groups: the sham group (n = 9), I/R non-treated group (n = 9), I/R-caffeic acid group (10 mg · kg⁻¹) (n = 9), I/R-caffeic acid group (30 mg · kg⁻¹) (n = 9) and I/R-caffeic acid group (50 mg · kg⁻¹) (n = 9). Global cerebral ischemia was induced by bilateral carotid artery occlusion for 20 min followed by reperfusion. Spatial learning and memory was evaluated using Morris water maze. Histopathological changes of hippocampus neurons was observed using HE staining. Superoxide dismutase (SOD, the antioxidant enzyme) activities and malondialdehyde (MDA, an oxidative stress biomarker) contents were detected. NF-κBp65 expression was detected by the methods of immunohistochemistry. Caffeic acid markedly reduced the escape latency, relieved hippocampal neurons injury and increased neuron count compared with those of I/R non-treated rat. NF-κBp65 expression and MDA content decreased significantly, and SOD activities increased significantly in hippocampus. Compared with sham group, 5-LO expression increase significantly in I/R non-treated group rat, and caffeic acid markedly reduced 5-LO expression. The results of the study suggest that caffeic acid has a significant protective effect on global cerebral ischemia-reperfusion injury in rats. The neuroprotective effects is likely to be mediated through the inhibition of 5-LO.

A Teaching Strategy with a Focus on Argumentation to Improve Undergraduate Students' Ability to Read Research Articles

The aim of this study is to evaluate a teaching strategy designed to teach first-year undergraduate life sciences students at a research university how to learn to read authentic research articles. Our approach-based on the work done in the field of genre analysis and argumentation theory-means that we teach students to read research articles by teaching them which rhetorical moves occur in research articles and how they can identify these. Because research articles are persuasive by their very nature, we focused on the rhetorical moves that play an important role in authors' arguments. We designed a teaching strategy using cognitive apprenticeship as the pedagogical approach. It was implemented in a first-year compulsory course in the life sciences undergraduate program. Comparison of the results of a pretest with those of the posttest showed that students' ability to identify these moves had improved. Moreover, students themselves had also perceived that their ability to read and understand a research article had increased. The students' evaluations demonstrated that they appreciated the pedagogical approach used and experienced the assignments as useful. On the basis of our results, we concluded that students had taken a first step toward becoming expert readers.

Vascular aspects of cognitive impairment and dementia

Hypertension and stroke are highly prevalent risk factors for cognitive impairment and dementia. Alzheimer's disease (AD) and vascular dementia (VaD) are the most common forms of dementia, and both conditions are preceded by a stage of cognitive impairment. Stroke is a major risk factor for the development of vascular cognitive impairment (VCI) and VaD; however, stroke may also predispose to AD. Hypertension is a major risk factor for stroke, thus linking hypertension to VCI and VaD, but hypertension is also an important risk factor for AD. Reducing these two major, but modifiable, risk factors-hypertension and stroke-could be a successful strategy for reducing the public health burden of cognitive impairment and dementia. Intake of long-chain omega-3 polyunsaturated fatty acids (LC-n3-FA) and the manipulation of factors involved in the renin-angiotensin system (e.g. angiotensin II or angiotensin-converting enzyme) have been shown to reduce the risk of developing hypertension and stroke, thereby reducing dementia risk. This paper will review the research conducted on the relationship between hypertension, stroke, and dementia and also on the impact of LC-n3-FA or antihypertensive treatments on risk factors for VCI, VaD, and AD.

Cardioprotective effects of fish omega-3 fatty acids on doxorubicin-induced cardiotoxicity in rats

The aim of this study was to investigate the protective effects of fish omega-3 (n-3) fatty acids on doxorubicin (DOX)-induced acute cardiotoxicity. A total of 24 rats were divided into three groups: control, DOX-treated, and DOX treated with fish n-3 fatty acids. Control group received 0.4 ml/kg/day of saline intragastrically. The rats in the fish n-3 fatty acid-pretreated group were given 400 mg/kg/day fish n-3 fatty acids for 30 days by intragastric intubation. To induce acute cardiotoxicity, DOX (30 mg/kg) was injected intraperitoneally by a single dose and the rats were killed after 48 h. DOX treatment caused severe damage in heart tissues. Disorganization of myocardial muscle fibers, myofibrillar loss, and cardiotoxic myocardial fibers with cytoplasmic vacuoles were seen. Fish n-3 fatty acid-treated rats showed an improved histological appearance in the DOX-treated group. Our data indicate a significant reduction in the activity of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling in cardiomyocytes of the DOX-treated group with fish n-3 fatty acids therapy. The DOX-treated with fish n-3 fatty acids group showed a significant decrease in malondialdehyde levels, and an increase in superoxide dismutase and glutathione peroxidase activities in comparison with the DOX-treated group. This study showed that fish n-3 fatty acids may be a suitable cardioprotector against acute toxic effects of DOX.

Fish oil provides robust and sustained memory recovery after cerebral ischemia: influence of treatment regimen

We previously reported that long-term treatment with fish oil (FO) facilitates memory recovery after transient, global cerebral ischemia (TGCI), despite the presence of severe hippocampal damage. The present study tested whether this antiamnesic effect resulted from an action of FO on behavioral performance itself, or whether it resulted from an anti-ischemic action. Different treatment regimens were used that were distinguished from each other by their initiation or duration with regard to the onset of TGCI and memory assessment. Naive rats were trained in an eight-arm radial maze, subjected to TGCI (4-VO model, 15 min), and tested for memory performance up to 6 weeks after TGCI. Fish oil (docosahexaenoic acid, 300 mg/kg/day) was given orally according to one of the following regimens: regimen 1 (from 3 days prior to ischemia until 4 weeks post-ischemia), regimen 2 (from 3 days prior to ischemia until 1 week post-ischemia), and regimen 3 (from week 2 to week 5 post-ischemia). When administered according to regimens 1 and 2, FO abolished amnesia completely. This effect persisted for at least 5 weeks after discontinuing the treatment. Such an effect did not occur, however, in the group treated according to regimen 3. Hippocampal and cortical damage was not alleviated by FO. The present results demonstrate that FO-mediated memory recovery (or preservation) following TGCI is a reproducible, robust, and long-lasting effect. Moreover, such an effect was found with a relatively short period of treatment, provided it covered the first days prior to and after ischemia. This suggests that FO prevented amnesia by changing some acute, ischemia/reperfusion-triggered process and not by stimulating memory performance on its own.

Therapeutic impact of eicosapentaenoic acid on ischemic brain damage following transient focal cerebral ischemia in rats

Long-chain n-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA), have been shown to reduce ischemic neuronal injury. We investigated the effects of ethyl-EPA (EPA-E) on ischemic brain damage using a rat transient focal cerebral ischemia model. Male Sprague-Dawley rats (n=105) were subjected to 90 min of focal cerebral ischemia. EPA-E (100mg/kg/day) or vehicle was administered once a day for 3, 5 or 7 days prior to ischemia. Different withdrawal intervals of 3, 5, and 7 days prior to ischemia following 7-day pretreatment with EPA-E or vehicle were also examined. In addition, post-ischemic administration of EPA-E was investigated. Pretreatment with EPA-E for 7 and 5 days, but not 3 days, showed significant infarct volume reduction and neurological improvements when compared with vehicle pretreatment. In addition, withdrawal of EPA-E administration for 3 days, but not 5 and 7 days, also demonstrated significant infarct volume reduction and neurological improvements when compared with vehicle treatment. Post-ischemic treatment of EPA-E did not show any neuroprotection. Immunohistochemistry revealed that 7-day pretreatment with EPA-E significantly reduced cortical expression of 8-hydroxydeoxyguanosine (maker for oxidative DNA damage), 4-hydroxy-2-nonenal (maker for lipid peroxidation), phosphorylated adducin (marker for Rho-kinase activation) and von Willebrand factor (endothelial marker) when compared with vehicle pretreatment. In addition, phosphorylated adducin expression co-localized with von Willebrand factor immunoreactivity. The present study established the neuroprotective effect of EPA-E on ischemic brain damage following transient focal cerebral ischemia in rats, which may be involved in the suppression of oxidative stress and endothelial Rho-kinase activation.

The protective effects of omega-3 fatty acid against toluene-induced neurotoxicity in prefrontal cortex of rats

OBJECTIVE

Toluene is used as an organic solvent, and it has neurotoxic effects. Omega-3 is an essential fatty acid required for brain development. The aim of this study was to investigate the protective effects of omega-3 fatty acid against toluene-induced neurotoxicity in prefrontal cortex of rats.

MATERIALS AND METHODS

A total of 21 male Wistar rats were divided into three groups with seven rats in each group. Rats in group I were the controls. Toluene was intraperitoneally injected into the rats of group II with a dose of 0.5 ml/kg. Rats in group III received omega-3 fatty acid with a dose of 0.4 g/kg/day while exposed to toluene. After 14 days, all the rats were killed by decapitation. Enzymatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and the level of malondialdehyde (MDA) were spectrophotometrically studied in the prefrontal cortex of rats.

RESULTS

Enzymatic activities of SOD and GSH-Px were decreased, and MDA levels were significantly increased in rats treated with toluene compared with the controls. However, the increased SOD and decreased GSH-Px enzymatic activities and MDA levels were detected in the rats administered with omega-3 fatty acid while exposed to toluene.

CONCLUSION

The results of this experimental study indicate that omega-3 fatty acid treatment can prevent toluene-induced neuronal damage in the prefrontal cortex of rats.

Expression of Bcl-2 and Bax after hippocampal ischemia in DHA + EPA treated rats

To determine the impact of ω3 fatty acids on post-ischemic expression of pro- and anti-apoptotic proteins in hippocampus, male rats were received 10 or 100 mg/kg [Docosahexaenoic acid (DHA) + Ecosapentaenoic acid (EPA); gavage; 21 days before ischemia to 2-10 days after ischemia]. Global cerebral ischemia reperfusion (IR) was performed using the four-vessel occlusion model; ischemia 8 min and reperfusion 6, 48 h and 10 days. IR increased Bcl-2 and Bax expression after 48 h (p < 0.05 and p < 0.01 vs. sham) and 10 days (only Bax; p < 0.05), without significant difference with DHA + EPA groups after 6 h. But after 48 h expression of Bcl-2 increased (p < 0.05 vs. IR) and Bax decreased (p < 0.05). At day 10 after ischemia expression of Bax in DHA + EPA acid groups was less than IR (p < 0.05) and in 100 mg/kg DHA + EPA group Bcl-2 expression was more than IR (p < 0.05). These data suggested that long-term gavage with DHA + EPA increase hippocampal neurons survival for days after ischemia, revealed by increased Bcl-2 and decreased Bax expressions.