Intranasal administration of fingolimod (FTY720) attenuates demyelination area in lysolecithin-induced demyelination model of rat optic chiasm.

BACKGROUND: Fingolimod (FTY720) is an oral immunosuppressive compound that has been prescribed to multiple sclerosis (MS) patients since 2010. The lipophilicity and low molecular weight of FTY720 allows it to cross blood brain barrier (BBB) and exert both peripheral and central effects. Previous reports showed that intranasal (IN) administration of drugs are the preferred non-invasive route, which bypasses BBB and improves their delivery and bioavailability in the central nervous system (CNS). Therefore, we aimed to compare the effects of IN and oral administrations of FTY720 on astrocyte activation and demyelination levels of optic chiasm in a focal demyelination model. METHODS: The experimental model was induced by injection of 2 µL lysolecithin 1% into the optic chiasm of male Wistar rats. The rats were treated by oral gavage or intranasal drop of FTY720 at dose of 0.3 mg/kg for 14 days. Astrocyte activation was analyzed using GFAP immunostaining, extent of demyelination, and myelination levels were measured by fluoromyelin staining, and MOG immunostaining, respectively. Then, the concentration of FTY720 was measured by high performance liquid chromatography (HPLC) method in brain tissues. RESULTS: Our data showed that IN administration of FTY720 significantly decreases astrocyte activation and demyelination levels in the optic chiasm compared to the oral administration route. In addition, the concentration of FTY720 was higher in the brain tissue of IN receiving rats compared to the oral treated group. CONCLUSION: It seems that IN administration of FTY720 may be a preferred route to decline the central inflammation and demyelination levels in the MS patients.

Fabrication and evaluation of novel quercetin-conjugated Fe3O4-ß-cyclodextrin nanoparticles for potential use in epilepsy disorder.

BACKGROUND: Despite the numerous pharmacological activities of quercetin, its biomedical application has been hampered, because of poor water solubility and low oral bioavailability. In the present study, we fabricated a novel form of quercetin-conjugated Fe3O4-ß-cyclodextrin (ßCD) nanoparticles (NPs), and the effect of these prepared NPs was evaluated in a chronic model of epilepsy. METHODS: Quercetin-loaded NPs were prepared using an iron oxide core coated with ßCD and pluronic F68 polymer. The chronic model of epilepsy was developed by intraperitoneal injection of pentylenetetrazole (PTZ) at dose of 36.5 mg/kg every second day. Quercetin or its nanoformulation at doses of 25 or 50 mg/kg were administered intraperitoneally 10 days before PTZ injections and their applications continued 1 hour before each PTZ injection. Immunostaining was performed to evaluate the neuronal density and astrocyte activation of hippocampi. RESULTS: Our data showed successful fabrication of quercetin onto Fe3O4-ßCD NPs. In comparison to free quercetin, quercetin NPs markedly reduced seizure behavior, neuronal loss, and astrocyte activation in a PTZ-induced kindling model. CONCLUSION: Overall, quercetin-Fe3O4-ßCD NPs might be regarded as an ideal therapeutic approach in epilepsy disorder.

Myristica Fragrans Houtt Extract Attenuates Neuronal Loss and Glial Activation in Pentylenetetrazol-Induced Kindling Model.

Inflammatory reactions are closely associated with the development and progression of epilepsy. It has been shown that inhibition of pro-inflammatory cytokines, which are released from activated astrocytes and microglia, are considered to be an effective therapeutic approach for the treatment of epileptic disorders. Regarding the anti-inflammatory effects of nutmeg (Myristica fragrans Houtt), the present study was designed to investigate whether the nutmeg ethanolic extract could exert anticonvulsant and inhibitory effects on glial activation in pentylenetetrazol (PTZ)-induced mice model of kindling. Ethanolic extract of nutmeg was administrated intraperitoneally (i.p.) 1 hour before PTZ injection or one week before PTZ as a separate group, to become fully-kindled. The chemical components of nutmeg extract were analyzed by gas chromatography mass spectrometry (GC-MS). Immunostaining against neuronal and glial markers was performed on hippocampus sections. GC-MS data indicated that the main components of nutmeg extract are myristic acid (39.93%), elemicin (22.16%) and myristicin (11.17%). Behavioral studies showed that pre-treatment of nutmeg extract effectively reduced seizures behavior, decreased cell death, and ameliorated glial activation that is followed by PTZ administration. In conclusion, nutmeg extract might be regarded as a useful supplementary agent in epilepsy treatment through its attenuation of neuronal loss and glial activation.

Fingolimod (FTY720) improves the functional recovery and myelin preservation of the optic pathway in focal demyelination model of rat optic chiasm.

It has been shown that fingolimod (FTY720) possesses beneficial effects on remyelination in the central nervous system (CNS). In this study, the effects of FTY720 and sodium valproate (VPA) as histone deacetylase inhibitor (HDAC) on the conductivity of visual signals, extent of demyelination area, glial activation, and expression levels of HDAC1and S1PR1 have been evaluated in the optic chiasm of lysolecithin (LPC)-induced demyelination model. In order to produce this demyelination model, LPC (1%, 2 µL) was injected into the rat optic chiasm. Latency of visual waves was measured by visual evoked potential (VEP) recording. The extent of demyelination area and level of glial activation were assessed using immunostaining. Gene expression analysis was performed to evaluate the expression levels of HDAC1, S1PR1, Olig2, and MBP in the optic chiasm. Analysis of electrophysiological data showed that LPC administration increased the latency of visual signals. FTY720 improved the functional recovery of the visual pathway and reduced the level of glial activation in the optic chiasm. FTY720 enhanced myelin repair and up-regulated the expression levels of Olig2 and MBP. Additionally, the expression levels of HDAC1 and S1PR1 were significantly reduced in animals treated with FTY720. In contrast to FTY720 treated animals, administration of VPA could not significantly improve the functional recovery of optic pathway following LPC injection. Cumulatively, the results of the present study demonstrate that FTY720 application improves the functional recovery of the optic pathway by reducing demyelination levels, amelioration of glial activation, and down-regulating of S1PR1 and HDAC1.

Upregulation of klotho and erythropoietin contributes to the neuroprotection induced by curcumin-loaded nanoparticles in experimental model of chronic epilepsy.

Klotho, which is a life extension factor, and erythropoietin (EPO) have been introduced as effective neuroprotective factors in several neurological disorders. The present study is an attempt to examine the potential role of klotho and EPO in therapeutic effect of curcumin-loaded nanoparticles (NPs) in pentylenetetrazol (PTZ)-induced kindling model. In order to induce the kindling model, PTZ was administrated intraperitoneally (i.p.) at dose of 36.5 mg/kg every other day for 20 days. Male NMRI mice received pre-treatment of free curcumin or curcumin-loaded NPs (12.5 mg/kg, i.p.) 10 days before PTZ injection and this was continued until 1 h before each PTZ injection. Immunostaining against NeuN, as a marker of neuronal maturation, and EPO was performed on hippocampal brain sections. Quantitative real time polymerase chain reaction (qRT-PCR) was conducted to assess the expression levels of tumor necrosis factor-α (TNF-α), klotho and EPO in the hippocampus. Immunostaining data indicated that treatment with curcumin-loaded NPs significantly alleviates the neuronal cell death in PTZ receiving animals. Curcumin-loaded NPs effectively upregulated the levels of EPO and klotho in PTZ receiving animals. Furthermore, mRNA level of TNF-α was considerably reduced in animals undergone curcumin-loaded NPs treatment. Overall, the results of this study suggest that downregulation of TNF-α and consequent upregulation of klotho and EPO might contribute to the neuroprotective effect of curcumin-loaded NPs in experimental model of epilepsy.

Curcumin-loaded nanoparticles ameliorate glial activation and improve myelin repair in lyolecithin-induced focal demyelination model of rat corpus callosum.

Curcumin has been introduced as effective anti-inflammatory agent in treatment of several inflammatory disorders. Despite the wide range pharmacological activities, clinical application of curcumin is restricted mainly due to the low water solubility of this substance. More recently, we could remarkably improve the aqueous solubility of curcumin by its encapsulation in chitosan-alginate-sodium tripolyphosphate nanoparticles (CS-ALG-STPP NPs). In this study, the anti-inflammatory and myelin protective effects of curcumin-loaded NPs were evaluated in lysolecithin (LPC)-induced focal demyelination model. Pharmacokinetic of curcumin was assessed using high performance liquid chromatography (HPLC). Local demyelination was induced by injection of LPC into corpus callosum of rats. Animals were pre-treated with intraperitoneal (i.p.) injections of curcumin or curcumin-loaded NPs at dose of 12.5 mg/kg, 10 days prior to LPC injection and the injections were continued for 7 or 14 days post lesion. Hematoxylin and eosin (H&E) staining and immunostaining against activated glial cells including astrocytes and microglia were carried out for assessment of inflammation level in lesion site. Myelin specific staining was performed to evaluate the effect of curcumin-loaded NPs on myelination of LPC receiving animals. HPLC results showed the higher plasma concentration of curcumin after administration of NPs. Histological evaluation demonstrated that, the extent of demyelination areas was reduced in animals under treatment of curcumin-loaded NPs. Furthermore, treatment with curcumin-loaded NPs effectively attenuated glial activation and inflammation in LPC-induced demyelination model compared to curcumin receiving animals. Overall; these findings indicate that treatment with curcumin-loaded NPs preserve myelinated axons through amelioration of glial activation and inflammation in demyelination context.

Piperine-loaded chitosan-STPP nanoparticles reduce neuronal loss and astrocytes activation in chemical kindling model of epilepsy.

Recent evidence suggests that encapsulation of hydrophobic drugs in biodegradable polymers opens a new horizon in nanomedicine filed. Piperine, a main alkaloid form of black pepper possesses potent anticonvulsant activity. However, the low water solubility of piperine has limited its clinical application. In this study, piperine was loaded on chitosan-sodium tripolyphosphate nanoparticles (CS-STPP NPs) and the effect of piperine NPs on seizures behavior and astrocytes activation was assessed in pentylentetrazol (PTZ)-induced kindling model. Animals have received the daily injection of free piperine or piperine NPs at doses of 5 or 10mg/kg, 10days before PTZ injections and their intraperitoneally (i.p) administration continued until the last PTZ injection. The neuroprotective effects of piperine NPs were evaluated using nissl staining and immunostaining against NeuN. Astrocytes activation was examined by GFAP immunostaining. Behavioral data showed that piperine NPs have inhibited the development of seizure parameters compared to the free piperine groups. In addition, the levels of cell loss and astrocytes activation were reduced in piperine NPs groups. In conclusion, these data suggest that piperine NPs enhance the neuroprotection and ameliorate the astrocytes activation in chemical kindling model of epilepsy. This may provide an effective therapeutic strategy for the treatment of epilepsy disorder.

Curcumin-loaded chitosan-alginate-STPP nanoparticles ameliorate memory deficits and reduce glial activation in pentylenetetrazol-induced kindling model of epilepsy.

Despite several beneficial effects of curcumin, its medical application has been hampered due to low water solubility. To improve the aqueous solubility of curcumin, it has been loaded on chitosan (CS)-alginate (ALG) - sodium tripolyphosphate (STPP) nanoparticles (NPs). Then, the effect of curcumin NPs on memory improvement and glial activation was investigated in pentylenetetrazol (PTZ)-induced kindling model. Male NMRI mice have received the daily injection of curcumin NPs at dose of 12.5 or 25mg/kg. All interventions were injected intraperitoneally (i.p), 10days before PTZ administration and the injections were continued until 1h before each PTZ injection. Spatial learning and memory was evaluated using Morris water maze test after the 7th PTZ injection. Animals have received 10 injections of PTZ and then, brain tissues were removed for histological evaluation. Nissl staining was used to determine the level of cell death in hippocampus and immunostaining method was performed against NeuN and GFAP/Iba1 for assessment of neuronal density and glial activation respectively. Behavioral results showed that curcumin NPs exhibit anticonvulsant activity and prevent cognitive impairment in fully kindled animals. The level of cell death and glial activation reduced in animals which have received curcumin NPs compared to those received free curcumin. To conclude, these findings suggest that curcumin NPs effectively ameliorate memory impairment and attenuate the level of activated glial cells in a mice model of chronic epilepsy.

Pregabalin enhances myelin repair and attenuates glial activation in lysolecithin-induced demyelination model of rat optic chiasm.

Multiple sclerosis (MS) is an autoimmune disease in which more than 70% of patients experience visual disturbance as the earliest symptoms. Lysolecithin (LPC)-induced focal demyelination model has been developed to evaluate the effects of different therapies on myelin repair improvement. In this study, the effects of pregabalin administration on myelin repair and glial activation were investigated. Local demyelination was induced by administration of LPC (1%, 2µL) into the rat optic chiasm. Rats underwent daily injection of pregabalin (30mg/kg, i.p) or vehicle. Visual-evoked potentials (VEPs) recordings were performed for evaluating the function of optic pathway on days 3, 7, 14 and 28 post lesions. Myelin specific staining and immunostaining against GFAP and Iba1 were also carried out for assessment of myelination and glial activation respectively. Electrophysiological data indicated that pregabalin administration could significantly reduce the P1-N1 latency and increase the amplitude of VEPs waves compared to saline group. Luxol fast blue staining and immunostaining against PLP, as mature myelin marker, showed that myelin repair was improved in animals received pregabalin treatment. In addition, pregabalin effectively reduced the expression of GFAP and Iba1 as activated glial markers in optic chiasm. The present study indicates that pregabalin administration enhances myelin repair and ameliorates glial activation of optic chiasm following local injection of LPC.