Subventricular zone-derived extracellular vesicles promote functional recovery in rat model of spinal cord injury by inhibition of NLRP3 inflammasome complex formation.

Spinal cord injury (SCI) is the destruction of spinal cord motor and sensory resulted from an attack on the spinal cord, which can cause significant physiological damage. The inflammasome is a multiprotein oligomer resulting in inflammation; the NLRP3 inflammasome composed of NLRP3, apoptosis-associated speck-like protein (ASC), procaspase-1, and cleavage of procaspase-1 into caspase-1 initiates the inflammatory response. Subventricular Zone (SVZ) is the origin of neural stem/progenitor cells (NS/PCs) in the adult brain. Extracellular vesicles (EVs) are tiny lipid membrane bilayer vesicles secreted by different types of cells playing an important role in cell-cell communications. The aim of this study was to investigate the effect of intrathecal transplantation of EVs on the NLRP3 inflammasome formation in SCI rats. Male wistar rats were divided into three groups as following: laminectotomy group, SCI group, and EVs group. EVs was isolated from SVZ, and characterized by western blot and DLS, and then injected into the SCI rats. Real-time PCR and western blot were carried out for gene expression and protein level of NLRP3, ASC, and Caspase-1. H&E and cresyl violet staining were performed for histological analyses, as well as BBB test for motor function. The results indicated high level in mRNA and protein level in SCI group in comparison with laminectomy (p < 0.001), and injection of EVs showed a significant reduction in the mRNA and protein levels in EVs group compared to SCI (p < 0.001). H&E and cresyl violet staining showed recovery in neural cells of spinal cord tissue in EVs group in comparison with SCI group. BBB test showed the promotion of motor function in EVs group compared to SCI in 14 days (p < 0.05). We concluded that the injection of EVs could recover the motor function in rats with SCI and rescue the neural cells of spinal cord tissue by suppressing the formation of the NLRP3 inflammasome complex.

Curcumin ameliorates experimental autoimmune encephalomyelitis in a C57BL/6 mouse model.

Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system. Although the exact etiology of the disease is largely unknown, it is identified that cytokines may play an important role in the pathogenesis of MS. In this study, the effects of curcumin has been investigated on the expression levels of selected cytokine coding genes as well as the extent of demyelination in the corpus callosum of C57BL/6 experimental autoimmune encephalomyelitis (EAE) model of MS. Gene expression analyses revealed that treatment with curcumin could lead to a significant reduction in the expression levels of pro-inflammatory cytokine coding genes including IL-6 (p = 0.001), IL-17 (p = 0.001), tumor necrosis factor (TNF)-α (p = 0.008), and interferon (IFN)-γ (p = 0.033) as well as a significant increase in the expression level of transforming growth factor (TGF)-ß (p = 0.006) as an anti-inflammatory cytokine. Moreover, the expression of glutathione peroxidase (GPX)-1 gene and the activity of anti-oxidant enzymes were significantly higher (p < 0.001) in curcumin-treated mice. Luxol fast blue staining also confirmed a significant reduction in the extent of demyelination in the curcumin-treated group (p < 0.001). Our results have confirmed that curcumin is an effective therapeutic agent that could ameliorate the severity of EAE.

Neuroprotective effect of exogenous melatonin on dopaminergic neurons of the substantia nigra in ovariectomized rats.

BACKGROUND: Melatonin has receptors in substantia nigra pars compacta (SNc) and regulates development of dopaminergic (DA) neurons. This study was undertaken to determine ability of melatonin to protect SNc dopaminergic neuron loss induced by estrogen deficiency in ovariectomized rats. METHODS: Female rats were randomized into four groups of seven each: control, ethanol sham, ovariectomy (ovx) and ovx with melatonin (ovx + m). In ovx, ovaries were removed. Ovx + m group was intraperitoneally injected with melatonin for 10 days, while the ethanol sham group received only ethanol. All rats were perfused with 4% paraformaldehyde, midbrains removed, fixed and paraffin embedded, then processed for Nissl and tyrosine hydroxylase staining (IHC). Ten sections of SNc in Nissl and IHC staining were analyzed in each animal, Nissl stained and tyrosine hydroxylase (TH) immunoreactive cells were counted in five experimental groups randomly. Data was analyzed using SPSS by ANOVA and t-test. Differences were considered significant for P<0.05. RESULTS: There was less cell number in ovx compared to control and ethanol sham groups significantly (P<0.001). The ovx + m group had more cells than the ovx group in the SNc significantly (P<0.001). Furthermore, there was significant decrease of TH positive cell number in the ovx group compared to control and ethanol sham groups (P<0.05). The number of TH immunoreactive cells was higher in ovx + m compared to the ovx group (P<0.05). CONCLUSION: These findings can be compared with human and used in clinical application for prevention of DA neuron death of SNc after ovariectomy.