Effect of Pentoxifylline on Apoptotic-Related Gene Expression Profile, Learning and Memory Impairment Induced by Systemic Lipopolysaccharide Administration in the Rat Hippocampus

Pentoxifylline protects memory performance in streptozotocin-induced diabetic rats

Diabetes, characterized by elevated blood glucose levels and associated organ damage, is reportedly correlated with adecline in cognitive functions with a potential involvement of oxidative stress mechanisms. Mitochondria-induced oxidative stress reported to cause hyperglycemia is believed to impair hippocampal neural plasticity, affecting long-term potentiation, and isconsidered crucial for maintaining memory functions. In this study, the neuroprotective effect of Pentoxifylline (PTX) for four weeks, an agent known for antioxidant and anti-inflammatory properties, was examined in an animal model of diabetes. In a streptozotocin (STZ) diabetic model, rats received intraperitoneal PTX (100 mg/kg), and learning and memory functions were tested using the radial arm water maze. STZ-treated diabetic rats exhibited impaired learning and memory functions (short/long-term, P < 0.05), whereas PTX treatment prevented these deficits. PTX treatment normalized diabetes-induced reduction in the protein expression levels of two enzymes of antioxidant defense superoxide dismutase and glutathione peroxidase (P < 0.05) in the hippocampal brain tissues. PTX treatment also mitigated STZ-induced increase in lipid peroxidation (TBARS, P < 0.05). Furthermore, reduced/oxidized glutathione (GSH/GSSG) ratios were enhanced in PTX-treated diabetic rats (P < 0.05), emphasizing the importance of redox balance restoration. However, PTX treatment did not significantly affect theantioxidant defense enzyme catalase activity. In conclusion, STZ-induced diabetes resulted in learning and memory impairment in rats, while PTX treatment prevented these effects, most likely via enhancement of antioxidant defense in the brain. This study highlights PTX's potential neuroprotective benefits, providing translational insights into the issue of diabetes-related cognitive complications.

Pentoxifylline as Add-On Treatment to Donepezil in Copper Sulphate-Induced Alzheimer's Disease-Like Neurodegeneration in Rats

Alzheimer's disease (AD), the most common neurodegenerative disorder, is characterized by behavioral, cognitive, and progressive memory impairments. Extensive neuronal loss, extracellular accumulation of insoluble senile amyloid-β (Aβ) plaques, and intracellular neurofibrillary tangles (NFTs) are the major pathological features. The present study aimed to investigate the therapeutic effect of donepezil (DON) and pentoxifylline (PTX) in combination to combat the neurodegenerative disorders (experimental AD) induced by CuSO4 intake in experimental rats. Thirty adult male Wistar rats (140-160 g) were used in this study. AD was first induced in rats by CuSO4 supplement to drinking water (10 mg/L) for 14 weeks. The AD group received no further treatment. Oral treatment with DON (10 mg/kg/day), PTX (100 mg/kg/day), or DON + PTX for the other three groups was started from the 10th week of CuSO4 intake for 4 weeks. Cortex markers like acetylcholine (ACh), acetylcholinesterase (AChE), total antioxidant capacity (TAC), and malondialdehyde (MDA) and hippocampus markers like β-amyloid precursor protein cleaving enzyme 1 (BACE1), phosphorylated Tau (p-tau), Clusterin (CLU), tumor necrosis factor-α (TNF-α), caspase-9 (CAS-9), Bax, and Bcl-2 were measured. The histopathology studies were done by using hematoxylin and eosin and Congo red stains as well as immunohistochemistry for neurofilament. CuSO4 induced adverse histological and biochemical changes. The histological injury in the hippocampus was inhibited following the administration of the DON and PTX. The brain tissue levels of AChE, MDA, BACE1, p-tau, CLU, CAS-9, Bax, and TNF-α were significantly increased, while brain tissue levels of ACh, TAC, and Bcl-2 were significantly decreased in CuSO4-treated rats as compared with the untreated control group. The effects induced by either DON or PTX on most studied parameters were comparable. Combined treatment of DON and PTX induced remarkable results compared with their individual use. However, more clinical and preclinical studies are still required to further confirm and prove the long-term efficacy of such combination.

Will Sirtuin 2 Be a Promising Target for Neuroinflammatory Disorders?

Neuroinflammatory disorder is a general term that is associated with the progressive loss of neuronal structure or function. At present, the widely studied diseases with neuroinflammatory components are mainly divided into neurodegenerative and neuropsychiatric diseases, namely, Alzheimer’s disease, Parkinson’s disease, depression, stroke, and so on. An appropriate neuroinflammatory response can promote brain homeostasis, while excessive neuroinflammation can inhibit neuronal regeneration and damage the central nervous system. Apart from the symptomatic treatment with cholinesterase inhibitors, antidepressants/anxiolytics, and neuroprotective drugs, the treatment of neuroinflammation is a promising therapeutic method. Sirtuins are a host of class III histone deacetylases, that require nicotinamide adenine dinucleotide for their lysine residue deacetylase activity. The role of sirtuin 2 (SIRT2), one of the sirtuins, in modulating senescence, myelin formation, autophagy, and inflammation has been widely studied. SIRT2 is associated with many neuroinflammatory disorders considering it has deacetylation properties, that regulate the entire immune homeostasis. The aim of this review was to summarize the latest progress in regulating the effects of SIRT2 on immune homeostasis in neuroinflammatory disorders. The overall structure and catalytic properties of SIRT2, the selective inhibitors of SIRT2, the relationship between immune homeostasis and SIRT2, and the multitasking role of SIRT2 in several diseases with neuroinflammatory components were discussed.