Neurobehavioral, biochemical and histological assessment of the effects of resveratrol on cuprizone-induced demyelination in mice: role of autophagy modulation

Resveratrol is known to exhibit neuroprotective effects in many neurological disorders via autophagy modulation. However, controversial results have been reported about the therapeutic potential of resveratrol and the implication of autophagy in demyelinating diseases. This study aimed to evaluate the autophagic changes in cuprizone-intoxicated C57Bl/6 mice and explore the effect of autophagy activation by resveratrol on the demyelination and remyelination processes. Mice were fed with chow containing 0.2% cuprizone for 5 weeks, followed by a cuprizone-free diet for 2 weeks. Resveratrol (250 mg/kg/day) and/or chloroquine (an autophagy inhibitor; 10 mg/kg/day) were given for 5 weeks starting from the third week. At the end of the experiment, animals were tested on rotarod and then sacrificed for biochemical assessment, luxol fast blue (LFB) staining, and transmission electron microscopy (TEM) imaging of the corpus callosum. We observed that cuprizone-induced demyelination was associated with impaired degradation of autophagic cargo, induction of apoptosis, and manifest neurobehavioral disturbances. Oral treatment with resveratrol promoted motor coordination and improved remyelination with regular compacted myelin in most axons without a significant impact on myelin basic protein (MBP) mRNA expression. These effects are mediated, at least in part, via activating autophagic pathways that may involve SIRT1/FoxO1 activation. This study verified that resveratrol dampens cuprizone-induced demyelination, and partially enhances myelin repair through modulation of the autophagic flux, since interruption of the autophagic machinery by chloroquine reversed the therapeutic potential of resveratrol. (AU)

Neurobehavioral, biochemical and histological assessment of the effects of resveratrol on cuprizone-induced demyelination in mice: role of autophagy modulation.

Resveratrol is known to exhibit neuroprotective effects in many neurological disorders via autophagy modulation. However, controversial results have been reported about the therapeutic potential of resveratrol and the implication of autophagy in demyelinating diseases. This study aimed to evaluate the autophagic changes in cuprizone-intoxicated C57Bl/6 mice and explore the effect of autophagy activation by resveratrol on the demyelination and remyelination processes. Mice were fed with chow containing 0.2% cuprizone for 5 weeks, followed by a cuprizone-free diet for 2 weeks. Resveratrol (250 mg/kg/day) and/or chloroquine (an autophagy inhibitor; 10 mg/kg/day) were given for 5 weeks starting from the third week. At the end of the experiment, animals were tested on rotarod and then sacrificed for biochemical assessment, luxol fast blue (LFB) staining, and transmission electron microscopy (TEM) imaging of the corpus callosum. We observed that cuprizone-induced demyelination was associated with impaired degradation of autophagic cargo, induction of apoptosis, and manifest neurobehavioral disturbances. Oral treatment with resveratrol promoted motor coordination and improved remyelination with regular compacted myelin in most axons without a significant impact on myelin basic protein (MBP) mRNA expression. These effects are mediated, at least in part, via activating autophagic pathways that may involve SIRT1/FoxO1 activation. This study verified that resveratrol dampens cuprizone-induced demyelination, and partially enhances myelin repair through modulation of the autophagic flux, since interruption of the autophagic machinery by chloroquine reversed the therapeutic potential of resveratrol.

Cytogenetic and testicular histological alterations induced by sulphur dioxide in dried apricot leather.

Sulphur dioxide (SO2) is used as a preservative in food to prevent its discolouration, and to inhibit the growth of bacteria. Little data is available concerning its in vivo hazardous impact.The present study is therefore designed to examine the cyto-genotoxic potential and the testicular histological alterations in adult mice, induced by SO2 present in the dried apricot leather used to prepare the oriental drink Qamar Al-Deen. Two different forms of drinks were tested; cold and boiled drinks. Animals were placed into 4 groups. The first group received distilled water as a negative control.The second and third groups received orally the drink for 28 days in the form of a cold and a boiled drink, respectively. Animals of the fourth group received cyclophosphamide, they were used as a positive control for cyto-genotoxic tests. The chromosomal aberrations, as well as sperm abnormalities, were significantly elevated in animals that received the two different drink preparations. The mitotic index significantly decreased in comparison with negative and positive controls. Furthermore, histological examination showed different degrees of alterations in the testis. Our results suggest that the presence of SO2 inside the apricot leather might be responsible for these changes. Thus, these remarkable hazardous effects of SO2 on male albino mice could be used as a potential guide for the prediction of its human health impact. Furthermore, consumers could be advised to prevent excessive consumption of the drink (Qamar Al-Deen) prepared from dried apricot leather.

Hyaluronic-Coated Albumin Nanoparticles for the Non-Invasive Delivery of Apatinib in Diabetic Retinopathy.

PURPOSE: Apatinib (Apa) is a novel anti-vascular endothelial growth factor with the potential to treat diabetic retinopathy (DR); a serious condition leading to visual impairment and blindness. DR treatment relies on invasive techniques associated with various complications. Investigating topical routes for Apa delivery to the posterior eye segment is thus promising but also challenging due to ocular barriers. Hence, the study objective was to develop Apa-loaded bovine serum albumin nanoparticles (Apa-BSA-NPs) coated with hyaluronic acid (HA); a natural polymer possessing unique mucoadhesive and viscoelastic features with the capacity to actively target CD44 positive retinal cells, for topical administration in DR. METHODS: Apa-BSA-NPs were prepared by desolvation using glutaraldehyde for cross-linking. HA-coated BSA-NPs were also prepared and HA: NPs ratio optimized. Nanoparticles were characterized for colloidal properties, entrapment efficiency (EE%), in vitro drug release and mucoadhesive potential. In vitro cytotoxicity on rabbit corneal epithelial cells (RCE) was assessed using MTT assay, while efficacy was evaluated in vivo in a diabetic rat model by histopathological examination of the retina by light and transmission electron microscopy. Retinal accumulation of fluorescently labeled BSA-NP and HA-BSA-NP was assessed using confocal microscope scanning. RESULTS: Apa-HA-BSA-NPs prepared under optimal conditions showed size, PdI and zeta potential: 222.2±3.56 nm, 0.221±0.02 and -37.3±1.8 mV, respectively. High EE% (69±1%), biphasic sustained release profile with an initial burst effect and mucoadhesion was attained. No evidence of cytotoxicity was observed on RCE cells. In vivo histopathological studies on DR rat model revealed alleviated retinal micro- and ultrastructural changes in the topical HA-Apa-BSA-NP treated eyes with normal basement membrane and retinal thickness comparable to normal control and intravitreally injected nanoparticles. Improved retinal accumulation for HA-BSA-NP was also observed by confocal microscopy. CONCLUSION: Findings present HA-Apa-BSA-NPs as a platform for enhanced topical therapy of DR overcoming the devastating ocular complications of the intravitreal route.

Hybrid bioactive hydroxyapatite/polycaprolactone nanoparticles for enhanced osteogenesis.

Hydroxyapatite nanoparticles (HApN) are largely employed as osteogenic inorganic material. Inorganic/polymeric hybrid nanostructures can provide versatile bioactivity for superior osteogenicity, particularly as nanoparticles. Herein, we present hybrid biomaterial-based hydroxyapatite/polycaprolactone nanoparticles (HAp/PCL NPs) realized using simple preparation techniques to augment HApN osteogenicity. Using wet chemical precipitation, we optimized HApN crystalline properties utilizing a 23-factorial design. Optimized HApN exhibited typical Ca/P elemental ratio with high reaction yield. Surface area analysis revealed their mesoporous nature and high surface area. Hybrid HAp/PCL NPs prepared using direct emulsification-solvent evaporation maintained HApN crystallinity with no observed chemical interactions. To the best of our knowledge, we are the first to elaborate the biocompatibility and osteogenicity of nanoparticulate hybrid HAp/PCL. Hybrid HAp/PCL NPs outperformed HApN regarding mesenchymal cell proliferation and osteodifferentiation with reduction of possible cytotoxicity. Unlike HApN, hybrid HAp/PCL NPs presented moderate expression of early osteogenic markers, Runx-2 and osteopontin and significantly elevated expression of the late osteogenic marker, bone sialoprotein after 10-day culture. Our results indicate that hybrid bioactive HAp/PCL NPs could offer a more prominent osteogenic potential than plain HApN for bone regenerative applications as a standalone nanoplatform or as part of complex engineered systems.

Impact of citrate- and chitosan-capped gold nanoparticles on the liver of Swiss albino mice: Histological and cyto-genotoxic study.

The present study aimed to disclose the histological alterations and cyto-genotoxic potential induced by citrate- and chitosan-capped AuNPs on liver of adult Swiss albino mice. Animals were randomly divided into 8 groups. The first two groups were intraperitoneally (i.p) injected with physiological saline once and left for 10 days and every other day for 21 days, respectively, and kept as negative control groups. While the third and fourth groups were injected i.p with a single dose of 2 mg/kg of citrate- and chitosan-capped AuNPs, respectively, and left for 10 days. The fifth and sixth groups were injected i.p every other day for 21 days with 200 µg/kg of citrate- and chitosan-capped AuNPs, respectively. Animals of the seventh and eighth groups were injected i.p with 50 mg/kg cyclophosphamide once and left for 10 days and with 20 mg/kg cyclophosphamide every other day for 21 days, respectively. The livers of mice were dissected and processed for microscopic examination and for analyzing the expression of inflammation-related genes using RT-PCR. In addition, bone marrow samples were taken to investigate the mitotic index and the chromosomal aberrations. The present study showed various degrees of structural changes in the liver of animals received AuNPs. Such changes were more prominent in animals treated with a single dose of AuNPs, particularly with citrate-capped AuNPs as compared to chitosan-capped AuNPs. Furthermore, genotoxic analysis did not reveal any genotoxicity for AuNPs with both coats. Therefore, chitosan-capped AuNPs were less hepatotoxic than citrate-capped ones. However, it has not been proven that AuNPs are genotoxic by both coats.