Novel insights into the molecular mechanisms underlying anti-nociceptive effect of myricitrin against reserpine-induced fibromyalgia model in rats: Implication of SIRT1 and miRNAs.

ETHNOPHARMACOLOGICAL RELEVANCE: Manilkara zapota (L.) P. Royen, also termed sapodilla or chikoo, is a significant plant in ethnomedicine because of its long history of traditional medical applications. In diverse cultures, sapodilla is believed to protect against oxidative stress, inflammation, and some chronic diseases because of its high antioxidant content. The naturally occurring antioxidant myricitrin (MYR) flavonoid is primarily found in the leaves and other plant parts of sapodilla and it is well-known for having therapeutic qualities and possible health advantages. AIM OF THE STUDY: To appraise the possible impact of MYR on a rat model of reserpine-induced fibromyalgia (FM) and explore its mechanism of action. MATERIALS AND METHODS: Isolation and identification of MYR with more than 99% purity from Manilkara zapota leaves were primarily done and confirmed through chromatographic and spectrophotometric techniques. To develop FM model, reserpine (RSP) was injected daily (1 mg/kg, s.c.) for three successive days. Then, MYR (10 mg/kg, i.p.) and pregabalin (PGB, 30 mg/kg, p.o.) were given daily for another five days. Behavioral changes were assessed through open field test (OFT), hot plate test, and forced swimming test (FST). Further analyses of different brain parameters and signaling pathways were performed to assess monoamines levels, oxidative stress, inflammatory response, apoptotic changes as well as silent information regulator 1 (SIRT1) and micro RNAs (miRNAs) expressions. RESULTS: From High-Performance Liquid Chromatography (HPLC) analysis, the methanol extract of sapodilla leaves contains 166.17 µg/ml of MYR. Results of behavioral tests showed a significant improvement in RSP-induced nociceptive stimulation, reduced locomotion and exploration and depressive-like behavior by MYR. Biochemical analyses showed that MYR significantly ameliorated the RSP-induced imbalance in brain monoamine neurotransmitters. In addition, MYR significantly attenuated oxidative stress elicited by RSP via up-regulating nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) protein expressions, enhancing superoxide dismutase (SOD) and catalase (CAT) activities, and reducing malondialdehyde (MDA) content in brain. The RSP-provoked inflammatory response was also diminished by MYR treatment as shown by a significant decreased NOD-like receptor protein 3 (NLRP3) inflammasome expression along with reduced levels of interleukin 1 beta (IL-1ß) and nuclear factor-κB (NF-κB). Furthermore, the anti-apoptotic activity of MYR was demonstrated by a marked rise in Bcl-2-associated X protein (BAX)/B cell lymphoma-2 (Bcl-2) ratio by lowering Bcl-2 while increasing BAX levels. In addition, MYR treatment significantly boosted the expression of SIRT1 deacetylase in RSP-treated animals. Interestingly, molecular docking showed the ability of MYR to form a stable complex in the binding site of SIRT1. Regarding miRNAs, MYR effectively ameliorated RSP-induced changes in miR-320 and miR-107 gene expressions. CONCLUSION: Our findings afford new insights into the anti-nociceptive profile of MYR in the RSP-induced FM model in rats. The underlying mechanisms involved direct binding and activation of SIRT1 to influence different signaling cascades, including Nrf2 and NF-κB/NLRP3 together with modulation of miRNAs. However, more in-depth studies are needed before proposing MYR as a new clinically relevant drug in the management of FM.

Effectiveness of epigallocatechin gallate nanoparticles on the in-vivo treatment of Alzheimer's disease in a rat/mouse model: a systematic review.

BACKGROUND: Alzheimer's disease (AD) is a neurological disease that causes memory loss over time. Current therapies are limited and frequently inadequate. Epigallocatechin gallate (EGCG), has antioxidant, anti-inflammatory, antifibrosis, anti-remodeling and tissue-protective qualities that may be effective in treatment of different diseases, including AD. Because of nanoparticles' high surface area, they can enhance solubility, stability, pharmacokinetics and biodistribution, and diminish toxicities. Besides, lipid nanoparticles have a high binding affinity that can enhance the rate of drug transport across BBB. So, EGCG nanoparticles represent a promising treatment for AD. OBJECTIVES: This systematic review sought to assess the efficacy of EGCG nanoparticles against AD in rat/mouse models. METHODS: Study was conducted in accordance with PRISMA guidelines, and the protocol was registered in PROSPERO. Electronic databases were searched to discover relevant studies published up to October 2022. RESULTS: Two studies met the inclusion criteria out of 1338 and were included in this systematic review. Collectively, the results indicate that EGCG has a significant potential for reducing AD pathology and improving cognitive deficits in rat/mouse models. The formulated particles were in the nanometer range, as indicated by TEM, with good particle size control and stability. EGCG nanoparticles showed superior pharmacokinetic characteristics and improved blood-brain barrier permeability, and increased brain bioavailability compared to free EGCG. Additionally, nanoEGCG were more effective in modulating oxidative stress than free formulation and decreased AChE in the cortex and hippocampus of AlCl3-treated rats. CONCLUSION: This systematic analysis of the two studies included showed that EGCG nanoparticles are efficacious as a potential therapeutic intervention for AD in rat/mouse models. However, limited number of studies found indicates insufficient data in this research point that requires further investigation by experimental studies.

P2 X 7 receptor is a critical regulator of extracellular ATP-induced profibrotic genes expression in rat kidney: implication of transforming growth factor-ß/Smad signaling pathway.

This study was designed to investigate the potential of extracellular adenosine 5'-triphosphate (ATP) via the P2 X 7 receptor to activate the renal fibrotic processes in rats. The present study demonstrates that administration of ATP rapidly activated transforming growth factor-ß (TGF-ß) to induce phosphorylation of Smad-2/3. Renal connective tissue growth factor (CTGF) and tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA and protein expressions were also increased following ATP administration. A decrease in TGF-ß amount in serum as well as renal Smad-2/3 phosphorylation was noticed in animals pre-treated with the specific antagonist of P2 X 7 receptor, A 438,079. In addition, a significant reduction in mRNA and protein expression of CTGF and TIMP-1were also observed in the kidneys of those animals. Collectively, the current findings demonstrate that ATP has the ability to augment TGF-ß-mediated Smad-2/3 phosphorylation and enhance the expression of the pro-fibrotic genes, CTGF and TIMP-1, an effect that is largely mediated via P2 X 7 receptor.

Further insights into the impact of rebamipide on gentamicin-induced nephrotoxicity in rats: modulation of SIRT1 and ß-catenin/cyclin D1 pathways.

Gentamicin (GM) is an effective antibiotic administered to treat acute Gram-negative infections. Nevertheless, its clinical application is limited due to nephrotoxicity. Therefore, our research aimed to investigate the potential renoprotective impact of rebamipide (RBM), a gastroprotective drug, on GM-induced kidney damage in rats, as well as putative nephroprotective pathways. RBM was orally administered (100 mg/kg/d for 14 d) commencing 7 d before the administration of GM (100 mg/kg/d, intraperitoneally). Nephrotoxicity was elucidated, and the silent information regulator 1 (SIRT1) and ß-catenin/cyclin D1 pathways were assessed. GM induced a significant elevation in the serum levels of creatinine, blood urea nitrogen (BUN), and kidney injury molecule-1 (KIM-1), as well as the relative kidney index. In addition, GM increased lipid peroxidation and lowered total antioxidant capacity (TAC) level and superoxide dismutase (SOD) activity. GM administration also demonstrated a significant amplification in tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1ß), nuclear factor-κappa B p65 (NF-κB p65), p38 mitogen-activated protein kinase (p38 MAPK), and caspase-3 kidney levels, as well as B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax)/Bcl-2 ratio. Notably, RBM treatment amended all these changes induced by GM. Furthermore, the potential role of SIRT1 and ß-catenin-dependent signaling pathways in GM-induced renal injury was assessed. Our findings showed that GM-treated rats demonstrated a substantial decrease in SIRT1, nuclear factor E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) along with an increase in ß-catenin, forkhead box O-3a (FOXO-3a), and cyclin D1 protein expressions. RMB treatment markedly attenuated the deterioration caused by GM on these pathways. Additionally, RBM alleviated the GM-induced deleterious kidney tissue histopathology. In conclusion, our findings have verified that RBM can halt GM-induced renal injury by partly modulating SIRT1 and ß-catenin pathways.

The protective effect of thymoquinone or/and thymol against monosodium glutamate-induced attention-deficit/hyperactivity disorder (ADHD)-like behavior in rats: Modulation of Nrf2/HO-1, TLR4/NF-κB/NLRP3/caspase-1 and Wnt/ß-Catenin signaling pathways in rat model.

Both thymoquinone (TQ) and thymol (T) have been proved to possess a positive impact on human health. In this research, we aimed to investigate the effect of these compounds separately and together on the Attention-deficit/hyperactivity disorder (ADHD)-like behavior induced by monosodium glutamate (MSG) in rats. Forty male, Spargue Dawley rat pups (postnatal day 21), were randomly allocated into five groups: Normal saline (NS), MSG, MSG+TQ, MSG+T, and MSG+TQ+T. MSG (0.4 mg/kg/day), TQ (10 mg/kg/day) and T (30 mg/kg/day) were orally administered for 8 weeks. The behavioral tests proved that rats treated with TQ and/or T showed improved locomotor, attention and cognitive functions compared to the MSG group with more pronounced effect displayed with their combination. All treated groups showed improvement in MSG-induced aberrations in brain levels of GSH, IL-1ß, TNF-α, GFAP, glutamate, calcium, dopamine, norepinephrine, Wnt3a, ß-Catenin and BDNF. TQ and/or T treatment also enhanced the mRNA expression of Nrf2, HO-1 and Bcl2 while reducing the protein expression of TLR4, NFκB, NLRP3, caspase 1, Bax, AIF and GSK3ß as compared to the MSG group. However, the combined therapy showed more significant effects in all measured parameters. All of these findings were further confirmed by the histopathological examinations. Current results concluded that the combined therapy of TQ and T had higher protective effects than their individual supplementations against MSG-induced ADHD-like behavior in rats.

Vinpocetine halts ketamine-induced schizophrenia-like deficits in rats: impact on BDNF and GSK-3ß/ß-catenin pathway.

There are increasing evidences supporting the involvement of oxidative stress and neuroinflammation in schizophrenia. Vinpocetine, a nootropic phosphodiesterase-1 inhibitor, was proven to possess anti-oxidant and anti-inflammatory potentials. This research aimed to reveal the likely protective features of vinpocetine against ketamine-induced schizophrenia-like deficits in rats. Additionally, the probable mechanisms contributing to this neuroprotection were also elucidated. Vinpocetine was given (20 mg/kg, i.p.) once a day for 14 days commencing 7 days before administrating ketamine (25 mg/kg i.p.). Risperidone was applied as a reference antipsychotic. Vinpocetine pre-treatment revealed a marked amendment in the hyperlocomotion, anxiety, and short-term memory deficits induced by ketamine in rats. In rats' hippocampus, ketamine induced a drastic increase in tissue levels of dopamine, lipid peroxidation, and pro-inflammatory cytokines along with a significant decrease in glutamate, GABA, SOD, and total anti-oxidant capacity. Also, ketamine induced a reduced level of BDNF together with the potentiation of GSK-3ß/ß-catenin pathway that led to the destruction of ß-catenin. Pre-treatment of ketamine-challenged animals with vinpocetine significantly attenuated oxidative stress, inflammation, and neurotransmitter alterations. Vinpocetine also elevated BDNF expression and prevented ketamine-induced stimulation of the GSK-3ß/ß-catenin signaling. This research presents enlightenments into the role of vinpocetine in schizophrenia. This role may be accomplished through its effect on oxidative stress, inflammation as well as modulating BDNF and the GSK-3ß/ß-catenin pathway.

Antifibrotic Effects of Carvedilol and Impact of Liver Fibrosis on Carvedilol Pharmacokinetics in a Rat model.

BACKGROUND AND OBJECTIVES: Carvedilol is a drug of choice in treatment of portal hypertension. The present study was designed to elucidate the potential role of antifibrotic effects of carvedilol in improving hepatic efficiency and the carvedilol oral pharmacokinetic changes during induction of liver fibrosis. METHODS: Rats were given CCl4 (1 ml/kg, intraperitoneal) twice weekly for 6 weeks and/or co-treated with carvedilol (10 mg/kg, orally) three times weekly on alternating days. Indocyanine green (ICG) clearance test was used as a modality for the measurement of hepatic blood flow. In addition, assessment of serum albumin as a marker of synthetic capacity and immunohistochemical staining of P-glycoprotein (P-gp) expression as a marker of metabolic capacity were done. Furthermore, hydroxyproline and TGF-ß1 were detected as markers of liver fibrosis. RESULTS: The area under plasma concentration-time curve of a single dose of carvedilol was significantly increased, associated with decreased the clearance in rats intoxicated with CCl4 compared to control group. Carvedilol co-treatment in CCl4-intoxicated rats for 6 weeks significantly counteracted the changes in hepatotoxicity markers and histopathological lesions induced by CCl4. In addition, there were no significant alterations in carvedilol pharmacokinetics between control and CCl4-intoxicated rats. Furthermore, carvedilol treatment restored liver efficiency, including synthetic and metabolic capacity as well as hepatic blood flow. CONCLUSION: The present study provides evidence underlying the antifibrotic effects of carvedilol and enhancement of hepatic efficiency. In addition, the pharmacokinetic parameters of a single dose of carvedilol are altered in liver fibrosis, manifested as delayed clearance. This was attributed to the reduction of both hepatic blood flow and CYP2D6 expression in the liver. Carvedilol co-treatment in CCl4-intoxicated rats for 6 weeks recovered its pharmacokinetic profile, which is mainly attributed to the impact of pharmacodynamic antifibrotic effects of carvedilol on its own kinetics.