Pharmacological interventions targeting insulin resistance, neuroinflammation and oxidative stress in Intracerebroventricular-Streptozocin induced rat model of Alzheimer’s disease
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1
Panjab University, Chandigarh, India
Alzheimer’s disease featuring dementia, cognitive deficits and behavioral alterations is one of the most common prevalent neurodegenerative diseases affecting majorly elderly people termed as sporadic AD. Global prevalence of AD is sharply increasing, expected to affect almost 115 million people by 2050. Downregulation of insulin signaling pathway of PI3K-AKT plays a significant role in the pathophysiology of AD.
ICV-STZ was used for the model of sporadic Alzheimer’s disease being established. Adult male Wistar rats (48) weighing 200-300 g bred in Central Animal House facility of Panjab University were used. Animals were randomly divided into 8 groups comprising 6 animals in each group as follows:
Group1. Control animals were not disease induced and received distilled water orally for 21 days.
Group 2. Sham operated animals were injected aCSF (ICV, 4µL) on day 0.
Group 3. Animals received ICV-STZ (3mg/kg) bilaterally (4µL) on day 0.
Group 4, 5 and 6: ICV-STZ rats were administered different doses (low, medium, high) of test drug by oral gavage for 21 days.
Group 7: ICV-STZ rats were administered rivastigmine (2mg/kg via oral gavage) as standard drug for 21 days.
Group 8: No stereotaxic surgery was done. Highest dose of the drug was given orally for 21 days.
Protocol lasted for 21 days, sacrificing animals on 22nd day followed by isolation of serum and dissection of cortex and hippocampus, preserving the same for further analysis.
Behavioral studies like Morris water maze was done for assesing spatial memory, novel object recognition for associative memory and actophotometer was performed for locomotor activity.
Biochemical estimations for antioxidant activity or oxidative stress such as reduced glutathione estimation, superoxide dismutase assay, catalase assay, glutathine peroxidase assay, myeloperoxidase assay, glutathione S-transferase assay, lipid peroxidation assay, and protein carbonylation assay were performed in the homogenates of cortex and hippocampus of the brain which are the specific regions for memory, learning and cognition. For nitrosative stress, nitrite estimation was done. Protein concentrations were determined by biuret method. Cholinergic activity was evaluted by acetylcholinesterase assay to assess the cholinergic dysfuntion which is one of the core pathology of dementia and AD.
Inflammatory cytokines like TNF-α, IL-6 was determined by ELISA method to evalute the neuroinflammation which are aggravated by insulin resistance. c-reactive protein, a marker of neuroinflammation and neurodegeneration was also determined by ELISA.
Mitochondrial dysfunction was evaluated estimating mitochondrial enzyme complex-I,II,III,IV depicting a picture of viable and nonviable neuronal cells.
Histopathology was done by H&E staining to find out apoptotic cells, neuroinflammation, and neurodegeneration.
Molecular techniques like western blotting for p-tau, amyloid-beta, Akt protein and RT-PCR for PI3-K, AKT, p-AKT, and GSK 3-β was performed for gene expression analysis. Downregulation of the insulin signaling pathway leads to decreased phosphorylation of PI3K/AKT, which in turn increases the GSK-3β activity. GSK-3β is one of the culprits for phosphorylation of tau protein and hence the formation of neurofibrillary tangles. NFT initiates neurodegeneration and pathology of AD causing impairment in learning, memory and cognitive functions.
Acknowledgements
I acknowledge University Grants Commision, New Delhi for providing the fund.
References
REFERENCE
Bhat, N. R. (2010). "Linking cardiometabolic disorders to sporadic Alzheimer’s disease: a perspective on potential mechanisms and mediators." Journal of neurochemistry 115(3): 551-562.
De Felice, F. G. and S. T. Ferreira (2014). "Inflammation, defective insulin signaling, and mitochondrial dysfunction as common molecular denominators connecting type 2 diabetes to Alzheimer disease." Diabetes: DB_131954.
de la Monte, S. M., M. Tong, et al. (2006). "Therapeutic rescue of neurodegeneration in experimental type 3 diabetes: relevance to Alzheimer's disease." Journal of Alzheimer's Disease 10(1): 89-109.
Evans, J. L., B. A. Maddux, et al. (2005). "The molecular basis for oxidative stress-induced insulin resistance." Antioxidants & redox signaling 7(7-8): 1040-1052.
Farkas, G., J. Márton, et al. (1998). "Experimental acute pancreatitis results in increased blood–brain barrier permeability in the rat: a potential role for tumor necrosis factor and interleukin 6." Neuroscience letters 242(3): 147-150.
Ferreira, S. T., J. R. Clarke, et al. (2014). "Inflammation, defective insulin signaling, and neuronal dysfunction in Alzheimer's disease." Alzheimer's & dementia 10(1): S76-S83.
Gasparini, L., W. J. Netzer, et al. (2002). "Does insulin dysfunction play a role in Alzheimer's disease?" Trends in Pharmacological Sciences 23(6): 288-293.
Havrankova, J. and J. Roth (1979). "Concentrations of insulin and of insulin receptors in the brain are independent of peripheral insulin levels: studies of obese and streptozotocin-treated rodents." The Journal of clinical investigation 64(2): 636-642.
Hemmings, B. A. and D. F. Restuccia (2012). "Pi3k-pkb/akt pathway." Cold Spring Harbor perspectives in biology 4(9): a011189.
Jindal, H., B. Bhatt, et al. (2014). "Alzheimer disease immunotherapeutics: then and now." Human vaccines & immunotherapeutics 10(9): 2741-2743.
Lee, J. C., J. T. Laydon, et al. (1994). "A protein kinase involved in the regulation of inflammatory cytokine biosynthesis." Nature 372(6508): 739.
M de la Monte, S. (2012). "Brain insulin resistance and deficiency as therapeutic targets in Alzheimer's disease." Current Alzheimer Research 9(1): 35-66.
Matioli, M. N. P. and R. Nitrini (2015). "Mechanisms linking brain insulin resistance to Alzheimer's disease." Dementia & Neuropsychologia 9(2): 96-102.
Moloney, A. M., R. J. Griffin, et al. (2010). "Defects in IGF-1 receptor, insulin receptor and IRS-1/2 in Alzheimer's disease indicate possible resistance to IGF-1 and insulin signalling." Neurobiology of aging 31(2): 224-243.
Penumathsa, S. V., M. Thirunavukkarasu, et al. (2008). "Resveratrol enhances GLUT‐4 translocation to the caveolar lipid raft fractions through AMPK/Akt/eNOS signalling pathway in diabetic myocardium." Journal of cellular and molecular medicine 12(6a): 2350-2361.
Qu, Z., Z. Jiao, et al. (2011). "Effects of streptozotocin-induced diabetes on tau phosphorylation in the rat brain." Brain research 1383: 300-306.
Sánchez-Margalet, V. and S. Najib (1999). "p68 Sam is a substrate of the insulin receptor and associates with the SH2 domains of p85 PI3K." FEBS letters 455(3): 307-310.
Suzanne, M. (2012). "Contributions of brain insulin resistance and deficiency in amyloid-related neurodegeneration in Alzheimer’s disease." Drugs 72(1): 49-66.
Yin, W., A. P. Signore, et al. (2007). "Preconditioning suppresses inflammation in neonatal hypoxic ischemia via Akt activation." Stroke 38(3): 1017-1024.
Keywords:
Key Words: ICV-STZ, PI3-K/AKT/GSK3-β, Insulin resistance, neuroinflammation, Cognition,,
ICV-STZ rats,
Pi3-akt signaling inhibitors,
GSK-3 (Glycogen synthase kinase 3),
Insulin resisitance,
Cognition
Conference:
Belgian Brain Congress 2018 — Belgian Brain Council, LIEGE, Belgium, 19 Oct - 19 Oct, 2018.
Presentation Type:
e-posters
Topic:
NOVEL STRATEGIES FOR NEUROLOGICAL AND MENTAL DISORDERS: SCIENTIFIC BASIS AND VALUE FOR PATIENT-CENTERED CARE
Citation:
Akhtar
A
(2019). Pharmacological interventions targeting insulin resistance, neuroinflammation and oxidative stress in Intracerebroventricular-Streptozocin induced rat model of Alzheimer’s disease.
Front. Neurosci.
Conference Abstract:
Belgian Brain Congress 2018 — Belgian Brain Council.
doi: 10.3389/conf.fnins.2018.95.00068
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Received:
29 Aug 2018;
Published Online:
17 Jan 2019.
*
Correspondence:
Mr. Ansab Akhtar, Panjab University, Chandigarh, Chandigarh, India, ansabakhtar@gmail.com