Effects of Calorie Restriction on Multiple Sclerosis: A Review of the Preclinical and Clinical Studies.

It has been indicated that calorie restriction (CR) leads to several neuroprotective effects against physiological aging and different neurodegenerative disorders. Unfortunately, the definite therapeutic strategy is not introduced for Multiple sclerosis (MS) as an autoimmune disease of central nervous system (CNS) and researchers are striving to find the best treatment procedures and then optimize them. More recently, several preclinical studies have reported beneficial effects of CR on MS. It was stated that CR can decline demyelination, improve remyelination and decrease neuroinflammation in animal model of MS, as well as reduce body weight and enhance emotional wellbeing in MS patients. In this context we designed this review to examine studies exploring the effects of CR on MS disease based on the clinical and animal models to highlight involved mechanistic implications and future prospective.

Mesenchymal Stem Cells Ameliorate Cuprizone-Induced Demyelination by Targeting Oxidative Stress and Mitochondrial Dysfunction.

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. The main causes of MS disease progression, demyelination, and tissue damage are oxidative stress and mitochondrial dysfunction. Hence, the latter are considered as important therapeutic targets. Recent studies have demonstrated that mesenchymal stem cells (MSCs) possess antioxidative properties and are able to target mitochondrial dysfunction. Therefore, we investigated the effect of transplanting Wharton's jelly-derived MSCs in a demyelination mouse model of MS in which mice were fed cuprizone (CPZ) for 12 weeks. CPZ is a copper chelator that impairs the activity of cytochrome oxidase, decreases oxidative phosphorylation, and produces degenerative changes in oligodendrocytes, leading to toxic demyelination similar to those found in MS patients. Results showed that MSCs caused a significant increase in the percentage of myelinated areas and in the number of myelinated fibers in the corpus callosum of the CPZ + MSC group, compared to the CPZ group, as assessed by Luxol fast blue staining and transmission electron microscopy. In addition, transplantation of MSCs significantly increased the number of oligodendrocytes while decreasing astrogliosis and microgliosis in the corpus callosum of the CPZ + MSC group, evaluated by immunofluorescence. Moreover, the mechanism by which MSCs exert these physiological effects was found to be through abolishing the effect of CPZ on oxidative stress markers and mitochondrial dysfunction. Indeed, malondialdehyde significantly decreased while glutathione and superoxide dismutase significantly increased in CPZ + MSC mice group, in comparison witth the CPZ group alone. Furthermore, cell therapy with MSC transplantation increased the expression levels of mitochondrial biogenesis transcripts PGC1α, NRF1, MFN2, and TFAM. In summary, these results demonstrate that MSCs may attenuate MS by promoting an antioxidant response, reducing oxidative stress, and improving mitochondrial homeostasis.

Calorie restriction promotes remyelination in a Cuprizone-Induced demyelination mouse model of multiple sclerosis.

Over the past few decades several attempts have been made to introduce a potential and promising therapy for Multiple sclerosis (MS). Calorie restriction (CR) is a dietary manipulation to reduce calorie intake which has been shown to improve neuroprotection and attenuate neurodegenerative disorders. Here, we evaluated the effect of 33% CR regimen for 4 weeks on the remyelination capacity of Cuprizone (CPZ) induced demyelination in a mouse model of MS. Results showed that CR induced a significant increase in motor coordination and balance performance in CPZ mice. Also, luxol fast blue (LFB) staining showed that CR regimen significantly improved the remyelination in the corpus callosum of CPZ + CR mice compared to the CPZ group. In addition, CR regimen significantly increased the transcript expression levels of BDNF, Sox2, and Sirt1 in the corpus callosum of CPZ mice, while decreasing the p53 levels. Moreover, CR regimen significantly decreased the apoptosis rate. Furthermore, astrogliosis (GFAP + astrocytes) and microgliosis (Iba-1 + microglia) were significantly decreased by CR regimen while oligodendrogenesis (Olig2+) and Sirt1 + cell expression were significantly increased in the corpus callosum of CPZ + CR mice compared to the CPZ group. In conclusion, CR regimen can promote remyelination potential in a CPZ-demyelinating mouse model of MS by increasing oligodendrocyte generation while decreasing their apoptosis.

In utero transplantation of neural stem cells ameliorates maternal inflammation-induced prenatal white matter injury.

Prenatal white matter injury is a serious problem due to maternal inflammation leading to postnatal disabilities. In this study, we used the periventricular leukomalacia (PVL) model as a common prenatal white matter injury by maternal administration of lipopolysaccharide (LPS). Neural stem cells (NSCs) have shown therapeutic ability in neurological disorders through a different mechanism such as immunomodulation. Here, we studied the preventive potential of NSCs following in utero transplantation into the embryonic lateral ventricle in an LPS-induced white matter injury model. Pregnant animals were divided into three groups and received phosphate buffered saline, LPS, or LPS + NSCs. The brains of offspring were obtained and evaluated by real-time polymerase chain reaction (PCR), immunohistochemy, enzyme-linked immunosorbent assay (ELISA), terminal deoxynucleotidyl transferase-mediated biotinylated-dUTP nick-end labeling (TUNEL), and caspase-3 activity assay. The LPS-induced maternal inflammation degenerated the myelin sheath in the offspring periventricular region which was associated with an increased microglial number, oligodendrocytes degeneration, proinflammatory cytokine secretion, and cell apoptosis. The transplanted NSCs homed into the brain and ameliorated the evaluated parameters. The expression of proinflammatory cytokines interleukin-1ß (IL-1ß), IL-6, and tumor necrosis factor-α (TNF-α), cell apoptosis and caspase-3 activity were inhibited by NSCs. In addition, Olig2 and myelin basic protein immunohistochemy staining showed that prenatal NSCs transplantation augmented the myelination in the periventricular white matter of offspring. In conclusion, we think that prenatal therapeutic strategies, such as in utero NSCs transplantation, may prevent prenatal white matter injury after birth.

Effect of the CSF1R inhibitor PLX3397 on remyelination of corpus callosum in a cuprizone-induced demyelination mouse model.

Multiple sclerosis (MS) is a chronic inflammatory disease affecting the central nervous system (CNS). Despite introducing multiple immunomodulatory approaches for MS, there are still major concerns about possible ways for improving remyelination in this disease. Microglia exert essential roles in regulation of myelination processes, and interaction between colony-stimulating factor 1 (CSF1) with its receptor CSF1R is considered as a key regulator of microglial differentiation and survival. The aim of this study was to investigate possible roles for a CSF1R inhibitor PLX3397 in recovery of central myelination processes. Chronic demyelination was induced in mice by addition of 0.2% cuprizone to the chow for 12 weeks. Next, animals were undergoing a diet containing 290 mg/kg PLX3397 to induce microglial ablation. The PLX3397 treatment caused a significant decrease in the rate of expression for the CSF1/CSF1R axis, and a reduction in the protein expressions for the microglial marker Iba-1 and for the oligodendrocyte marker Olig-2. Findings from Luxol fast blue (LFB) staining and transmission electron microscopy (TEM) showed an increase in the rate of myelination for the mice receiving PLX3397. The rate of destruction in the nerve fibers and the extent of the gaps formed between layers of myelin sheaths was also reduced after the treatment with PLX3397. In addition, animals experienced an improvement in recovery of motor deficit after receiving PLX3397 (for all P < 0.05). It could be concluded that PLX3397 could retain myelination in the MS model possibly through regulation of the myelin environment.

Macrophage polarity in cancer: A review.

Macrophages are the most abundant cells within the tumor stroma displaying noticeable plasticity, which allows them to perform several functions within the tumor microenvironment. Tumor-associated macrophages commonly refer to an alternative M2 phenotype, exhibiting anti-inflammatory and pro-tumoral effects. M2 cells are highly versatile and multi-tasking cells that directly influence multiple steps in tumor development, including cancer cell survival, proliferation, stemness, and invasiveness along with angiogenesis and immunosuppression. M2 cells perform these functions through critical interactions with cells related to tumor progression, including Th2 cells, cancer-associated fibroblasts, cancer cells, regulatory T cells (Tregs), and myeloid-derived suppressor cells. M2 cells also have negative cross-talks with tumor suppressor cells, including cytotoxic T cells and natural killer cells. Programed death-1 (PD-1) is one of the key receptors expressed in M2 cells that, upon interaction with its ligand PD-L1, plays cardinal roles for induction of immune evasion in cancer cells. In addition, M2 cells can neutralize the effects of the pro-inflammatory and anti-tumor M1 phenotype. Classically activated M1 cells express high levels of major histocompatibility complex molecules, and the cells are strong killers of cancer cells. Therefore, orchestrating M2 reprogramming toward an M1 phenotype would offer a promising approach for reversing the fate of tumor and promoting cancer regression. Macrophage switching toward an anti-inflammatory M1 phenotype could be used as an adjuvant with other approaches, including radiotherapy and immune checkpoint blockades, such as anti-PD-L1/PD-1 strategies.

Astrocyte ablation induced by La-aminoadipate (L-AAA) potentiates remyelination in a cuprizone demyelinating mouse model.

Chronic demyelination in the central nervous system (CNS) is accompanied by an increase in the number of reactive astrocytes and astrogliosis. There are controversial issues regarding astrocytes and their roles in demyelinating diseases in particular for multiple sclerosis (MS). We aimed to evaluate possible roles for pharmacologic astrocyte ablation strategy using La-aminoadipate (L-AAA) on remyelination in a cuprizone model of demyelination. Male C57BL/6 mice were fed with 0.2% cuprizone for 12 weeks followed by 2-week administration of L-AAA through a cannula inserted 1 mm above the corpus callosum. Rotarod test showed a significant decrease in the range of motor coordination deficits after ablation of astrocytes in mice receiving cuprizone. Results of Luxol fast blue (LFB) and transmission electron microscopy (TEM) for evaluation of myelin content within the corpus callosum revealed a noticeable rise in the percentage of myelinated areas and in the number of myelinated fibers after L-AAA administration in the animals. Astrocyte ablation reduced protein expressions for GFAP (an astrocyte marker) and Iba-1 (a microglial marker), but increased expression of Olig2 (an oligodendrocyte marker) assessed by immunofluorescence. Finally, expression of genes related to recruitment of microglia (astrocyte chemokines CXCL10 and CXCL12) and suppression of oligodendrocyte progenitor cell (OPC) differentiation (astrocyte peptides ET-1 and EDNRB) showed a considerable decrease after administration of L-AAA (for all p < 0.05). These results are indicative of improved remyelination after ablation of astrocytes possibly through hampering microgliosis and astrogliosis and a further rise in the number of matured Olig2+ cells.

Resveratrol pretreatment enhanced homing of SDF-1α-preconditioned bone marrow-derived mesenchymal stem cells in a rat model of liver cirrhosis.

Stromal cell-derived factor-1α (SDF-1α) has been known to implicate in homing of MSCs, and resveratrol has been reported to have a positive influence on SDF-1 level in the site of injury. In this study, a combined strategy was applied to evaluate bone marrow-derived MSCs (BMSCs) homing to the rat model of liver cirrhosis induced by common bile duct ligation (CBDL): (1) pretreatment delivery of resveratrol into the cirrhotic liver, and (2) transplantation of ex vivo BMSC preconditioning with SDF-1α. BMSCs were preconditioned with 10 ng/µL SDF-1α for 1 h and then labeled with the CM-Dil. Cirrhosis was induced by CBDL. Animals received intraperitoneal injection of resveratrol for 7 days, started on day 28 of CBDL post-operative. On day 36 post-operative, 1 × 106 of SDF-1α-preconditioned BMSCs was injected via caudal vein. Animals were sacrificed at 72 h post-cell transplantation. Immunofluorescence and flow cytometry assessments showed that the BMSC+SDF+RV group had an increased rate of homing into the liver, but it had a decreased rate of homing into the lung and spleen, as compared with the other groups (P < 0.05). The BMSC+SDF+RV group showed high protein expression of SIRT1, but low protein expression of p53 in the liver (P < 0.05 vs other groups). CXCR4 and matrix metalloproteinase (MMP)-9 highly expressed in SDF-1α-preconditioned BMSCs in vitro, and that AKTs and CXCL12 expressed in injured liver undergoing resveratrol injection. Our findings suggest that reseveratrol pretreatment prior to SDF-1α preconditioning could be a promising strategy for designing cell-based therapies for liver cirrhosis.

Preconditioning with melatonin improves therapeutic outcomes of bone marrow-derived mesenchymal stem cells in targeting liver fibrosis induced by CCl4.

Preconditioning of mesenchymal stem cells (MSCs) with melatonin (MT) has shown promising results in animal models of myocardial infarction, renal ischemia and cerebral ischemia. Here, we use this strategy in the liver fibrosis induced by CCl4. There were five groups: normal, CCl4, CCl4 + vehicle, CCl4 + BMMSCs and CCl4 + MT-bone marrow (BM)-derived MSCs (MT-BMMSCs). CCl4 was injected twice weekly for 8 weeks and treatment either with cells or vehicle was performed at the beginning of week 5 with a single dose. BMMSCs were preconditioned with MT for 24 h before injection. MT-BMMSCs had a high ability of homing into the injured liver (P ≤ 0.05 vs. BMMSCs). The CCl4 + MT-BMMSCs group showed higher percentage of glycogen storage but lower percentage of collagen and lipid accumulation (P ≤ 0.05 vs. CCl4 + BMMSCs). The CCl4 + MT-BMMSCs group showed lower expressions of transforming growth factor-ß1 (TGF-ß1) and Bax and lower content of sera alanine aminotransferase (ALT) but higher expressions of matrix metalloproteinases (MMPs) and Bcl2 compared with the BMMSCs group (P ≤ 0.05). The results showed the better therapeutic outcomes of MT preconditioning by probably improving cell homing and also better maintenance of the balance between matrix degrading and accumulating factors.

Stimulation of neurotrophic factors and inhibition of proinflammatory cytokines by exogenous application of triiodothyronine in the rat model of ischemic stroke.

There is a positive relation between decreases of triiodothyronine (T3) amounts and severity of stroke. The aim of this study was to evaluate the effect of exogenous T3 application on levels of neurogenesis markers in the subventricular zone. Cerebral ischemia was induced by middle cerebral artery occlusion in male Wistar rats. There were 4 experimental groups: sham, ischemic, vehicle, and treatment. Rats were injected with T3 (25 µg/kg, IV injection) at 24 hours after ischemia. Animals were sacrificed at day 7 after ischemia. There were high levels of brain-derived neurotrophic factor, nestin, and Sox2 expressions in gene and protein levels in the T3 treatment group (P ≤ .05 vs ischemic group). Treatment group showed high levels of sera T3 and thyroxine (T4) but low levels of thyrotropin (TSH), tumor necrosis factor-α, and interleukin-6 (P ≤ .05 vs ischemic group) at day 4 after ischemia induction. Findings of this study revealed the effectiveness of exogenous T3 application in the improvement of neurogenesis possibly via regulation of proinflammatory cytokines.

Retinoic acid-pretreated Wharton's jelly mesenchymal stem cells in combination with triiodothyronine improve expression of neurotrophic factors in the subventricular zone of the rat ischemic brain injury.

Stroke is the consequence of limited blood flow to the brain with no established treatment to reduce the neurological deficits. Focusing on therapeutic protocols in targeting subventricular zone (SVZ) neurogenesis has been investigated recently. This study was designed to evaluate the effects of retinoic acid (RA)-pretreated Wharton's jelly mesenchymal stem cells (WJ-MSCs) in combination with triiodothyronine (T3) in the ischemia stroke model. Male Wistar rats were used to induce focal cerebral ischemia by middle cerebral artery occlusion (MCAO). There were seven groups of six animals: Sham, Ischemic, WJ-MSCs, RA-pretreated WJ-MSCs, T3, WJ-MSCs +T3, and RA-pretreated WJ-MSCs + T3. The treatment was performed at 24 h after ischemia, and animals were sacrificed one week later for assessments of retinoid X receptor ß (RXRß), brain-derived neurotrophic factor (BDNF), Sox2 and nestin in the SVZ. Pro-inflammatory cytokines in sera were measured at days four and seven after ischemia. RXRß, BDNF, Sox2 and nestin had the significant expressions in gene and protein levels in the treatment groups, compared with the ischemic group, which were more vivid in the RA-pretreated WJ-MSCs + T3 (p ≤ 0.05). The same trend was also resulted for the levels of TNF-α and IL-6 at four days after ischemia (p ≤ 0.05). In conclusion, application of RA-pretreated WJ-MSCs + T3 could be beneficial in exerting better neurotrophic function probably via modulation of pro-inflammatory cytokines.

Evaluation of the effect of adipose tissue-derived stem cells on the quality of bone healing around implants.

PURPOSE/AIM: This study evaluates the efficacy of grafted adipose-derived stem cells (ADSCs) on blade-type implants in improving osseointegration in rat femurs using a low-density bone model. MATERIALS AND METHODS: After isolating and expanding ADSCs, twice-passaged cells were seeded on blade-type implants on culture plates. Osteogenic induction of grafted cells began after attaching cells to the prepared titanium surfaces and it continued for 4 days. The scaffolds were then implanted in the femurs of Wistar rats. Osteogenic differentiation of these cells was confirmed using polymerase chain reaction (PCR) and alizarin red staining of the mineralized extracellular matrix. After 8 weeks, histological and histomorphometric evaluations of undecalcified resin sections (bone-implant contact [BIC] % and bone mineral index [BMI]) were performed using light microscopy and scanning electron microscopy. RESULTS: Alizarin red staining in conjunction with gene expression results confirmed osteogenic differentiation. Histomorphometric assessment using scanning electron microscopy demonstrated improved BIC% and BMI near the treated surface compared with the untreated surface. CONCLUSIONS: The complex of differentiated grafted ADSCs and extracellular matrix and the macrodesign and microdesign of the implant can improve osseointegration in low-density bone.

Evaluation of Simvastatin and Bone Marrow-Derived Mesenchymal Stem Cell Combination Therapy on Airway Remodeling in a Mouse Asthma Model.

INTRODUCTION: The effect of bone marrow-derived mesenchymal stem cells (BMSCs) on asthma treatment was shown in our previous study. Several studies have shown the effect of statins on BMSC preservation and migration to sites of inflammation. In this study, the effects of simvastatin and BMSC combination therapy in an ovalbumin-induced asthma model in mouse were examined. METHODS: Four groups of BALB/c mice were studied including control group (animals were not sensitized), asthma group (animals were sensitized by ovalbumin), asthma + simvastatin group (asthmatic animals were treated with simvastatin), and asthma + BMSC + simvastatin group (asthmatic animals were treated with simvastatin and BMSCs). BMSCs were isolated, characterized, labeled with BrdU, and transferred into asthmatic mice. BMSC migration, airways histopathology, and total and differential white blood cell (WBC) count in bronchoalveolar lavage (BAL) fluid were evaluated. RESULTS: A significant increase in the number of BrdU-BMSCs was found in the lungs of mice treated with simvastatin + BMSCs compared to mice treated with BMSCs. The histopathological changes, BAL total WBC counts, and the percentage of neutrophils and eosinophils were increased in asthma group compared to the control group. Treatment with simvastatin significantly decreased airway inflammation and inflammatory cell infiltration. Combination therapy improved all measured parameters higher than simvastatin. Goblet cell hyperplasia and subepithelial fibrosis were also decreased in combination therapy group. CONCLUSION: These results indicated that simvastatin and BMSC combination therapy was superior to simvastatin therapy and BMSC therapy alone in reduction of airway remodeling and lung inflammation in the ovalbumin-induced asthma model in mouse.

Regulatory effect of triiodothyronine on brain myelination and astrogliosis after cuprizone-induced demyelination in mice.

Chronic demyelination and plaque formation in multiple sclerosis is accompanied by persisting astrogliosis, negatively influencing central nervous system recovery and remyelination. Triiodothyronin (T3) is thought to enhance remyelination in the adult brain by the induction of oligodendrocyte maturation. We investigated additional astrocyte-mediated mechanisms by which T3 might promote remyelination in chronically demyelinated lesions using the cuprizone mouse model. C57BL/6 mice were fed cuprizone for 12 weeks to induce lesions with an impaired remyelination capacity. While the expression of oligodenrocyte progenitor markers, i.e., platelet derived growth factor-α receptor was not affected by T3 administration, myelination status, myelin protein expression as well as total and adult oligodendrocyte numbers were markedly increased compared to cuprizone treated controls. In addition to these effects on oligodendrocyte numbers and function, astrogliosis but not microgliosis was ameliorated by T3 administration. Intermediate filament proteins vimentin and nestin as well as the extracellular matrix component tenascin C were significantly reduced after T3 exposure, indicating additional effects of T3 on astrocytes and astrogliosis. Our data clearly indicate that T3 promotes remyelination in chronic lesions by both enhancing oligodendrocyte maturation and attenuating astrogliosis.

Effects of Platelet-Rich Plasma & Platelet-Rich Fibrin with and without Stromal Cell-Derived Factor-1 on Repairing Full-Thickness Cartilage Defects in Knees of Rabbits.

BACKGROUND: The purpose of this study was to create biomaterial scaffolds like platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) containing stromal cell-derived factor-1 (SDF1) as a chemokine to induce hyaline cartilage regeneration of rabbit knee in a full thickness defect. METHODS: We created a full thickness defect in the trochlear groove of thirty-six bilateral knees of eighteen mature male rabbits. The knees were randomly divided into six groups (group I: untreated control, group II: PRP, group III: PRF, group IV: Gelatin+SDF1, group V: PRP+SDF1, and group VI: PRF+SDF1). After four weeks, the tissue specimens were evaluated by macroscopic examination and histological grading, immunofluorescent staining for collagen type II, and analyzed for cartilage marker genes by real-time PCR. The data were compared using statistical methods (SPSS 20, Kruskal-Wallis test, Bonferroni post hoc test and P<0.05). RESULTS: Macroscopic evaluations revealed that international cartilage repair society (ICRS) scores of the PRF+SDF1 group were higher than other groups. Microscopic analysis showed that the ICRS score of the PRP group was significantly lower than other groups. Immunofluorescent staining for collagen II demonstrated a remarkable distribution of type II collagen in the Gel+SDF1, PRP+SDF1 and PRF+SDF1 groups compared with other groups. Real-time PCR analysis revealed that mRNA expression of SOX9 and aggrecan were significantly greater in the PRF+SDF1, PRP+SDF1, Gel+SDF1 and PRF groups than the control group (P<0.05). CONCLUSION: Our results indicate that implantation of PRF scaffold containing SDF1 led to the greatest evaluation scores of full-thickness lesions in rabbits.

Homing of allogeneic nestin-positive hair follicle-associated pluripotent stem cells after maternal transplantation in experimental model of cortical dysplasia.

An embryo has the capability to accept allo- or xeno-geneic cells, which probably makes it an ideal candidate for stem cell transplantation of various cerebral cortex abnormalities, such as cortical dysplasia. The aim of this study was to determine hair follicle-associated pluripotent (HAP) stem cells homing into various organs of mother and fetus. Cells were obtained, analyzed for immunophenotypic features, and then labelled with CM-Dil; nestin(+)HAP stem cells or media phosphate-buffered saline (PBS) were intravenously delivered on day 16 of gestation in BALB/c mice, which intraperitoneally received methylazoxymethanol (MAM) one day in advance, and homing was assessed at 24 h after cell injection. Flow cytometry and immunocytochemistry manifested positive expression of nestin in HAP stem cells. For both mother and fetus, brain, lungs, liver, and spleen were the host organs for cell implants. For the brain, the figure was considerably higher in fetus, 4.05 ± 0.5% (p ≤ 0.05 vs. mother). MAM-injected mice had a downward trend for SDF-1α and CXCR4 (p ≤ 0.05 vs. control), but HAP stem cells group showed an upward trend for CXCR4 (p ≤ 0.05 vs. MAM). We conclude the HAP stem cells show homing potential in experimental cortical dysplasia, which may permit these cells to be a target in future work on prenatal therapy of neural disorders.

Progesterone Enhanced Remyelination in the Mouse Corpus Callosum after Cuprizone Induced Demyelination.

BACKGROUND: Progesterone as a sex steroid hormone is thought to affect and prevent demyelination, but its role in promoting myelin repair is far less investigated. In this study, remyelinating potential of progesterone in corpus callosum was evaluated on an experimental model of MS. METHODS: In this experimental study, adult male C57BL/6 mice were fed with 0.2% (w/w) cuprizone in ground breeder chow ad libitum for 6 weeks. At day zero, after cuprizone removal, mice were divided randomly into two groups: (a) placebo group, which received saline pellet implant, (b) progesterone group, which received progesterone pellet implant. Some mice of the same age were fed with their normal diet to serve as the healthy control group. Two weeks after progesterone administration, Myelin content was assessed by Luxol-fast blue staining. The myelin basic protein (MBP) and proteolipid protein (PLP) expression were assessed using Western blot analysis and the changes in the number of oligodendrocytes and oligodendroglial progenitor cells were assessed by immunohistochemistry (IHC) and flow cytometry. RESULTS: Luxol-fast blue staining revealed enhanced remyelination in the progesterone group when compared with the placebo group. Densitometry measurements of immunoblots demonstrated that MBP and PLP proteins contents were significantly increased in the progesterone group compared with the placebo group. Flow cytometry and IHC analysis showed increases in Olig2 and O4 cells in the progesterone group compared with the placebo group. CONCLUSION: Overall, our results indicate that progesterone treatment can stimulate myelin production and that it may provide a feasible and practical way for remyelination in diseases such as multiple sclerosis.