An Experimental Study on the Mechanical and Biological Properties of Bio-Printed Alginate/Halloysite Nanotube/Methylcellulose/Russian Olive-Based Scaffolds

Purpose: Cartilage shows neither repairs nor regenerative properties after trauma or gradual wear and causes severe pain due to bones rubbing. Bioprinting of tissue-engineered artificial cartilage is one of the most fast-growing sciences in this area that can help millions of people against this disease. Methods: Bioprinting of proper bioscaffolds for cartilage repair was the main goal of this study. The bioprinting process was achieved by a novel composition consisting of alginate (AL), Halloysite nanotube (HNT), and methylcellulose (MC) prepared in bio-ink. Also, the effect of Russian olive (RO) in chondrocytes growth on bioscaffolds was also investigated in this work. Compressive, hardness and viscosity tests, Energy-Dispersive X-Ray Spectroscopy (EDX), Fourier-Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), water-soluble Tetrazolium (WST) assay, and also transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were carried out. Results: The results show that in constant concentrations of AL, MC, and RO (20 mg/ml AL, 20 mg/ml MC, and 10 mg/ml RO) when concentration of HNT increased from 10 mg/ml (T-7) to 20 mg/ml (T-8) compressive stiffness increased from 241±45 kPa to 500.66±19.50 kPa. Also, 20 mg/ml of AL in composition saved proper water content for chondrocyte growth and produced good viscosity properties for a higher printing resolution. Conclusion: RO increased chondrocytes living cell efficiency by 11% on bioprinted scaffolds in comparison with the control group without RO. Results obtained through in-vivo studies were similar to those of in-vitro studies. According to the results, T-7 bio-ink has good potential in bioprinting of scaffolds in cartilage repairs

Medical Students’ View about the Effects of Practical Courses on Learning the General Theoretical Concepts of Basic Medical Sciences

Introduction: The basic medical sciences section requires 2.5 years in the medical education curriculum. Practical courses complement theoretical knowledge in this period to improve their appreciation. Despite spending lots of disbursement and time, this period’s efficacy is not clearly known. Methods: One hundred thirty-three General Practitioner (GP) students have been included in this descriptive cross-sectional study and were asked by questionnaire about the positive impact of practical courses on learning theoretical knowledge. Data were analyzed by descriptive statistics. Result: The agreement in “Practical Head and Neck Anatomy” was 40.91% ± 29.45, in “Practical Trunk Anatomy” was 63.62% ± 2.32 and in “Practical Anatomy of Extremities” was 56.16% ± 2.57. In “Practical Histology”, agreement was 69.50%±2.19; “Practical Biophysics” was 45.97%±2.25, “Practical Physiology” 61.75%±2.17; “Practical Biochemistry” 36.28%±2.42; “Practical Pathology” 59.80%±2.53; “Practical Immunology” 56.25%±26.40; “Practical Microbiology and Virology” 60.39%±2.27 and “Practical Mycology and Parasitology” 68.2%± 2.16.Conclusion: GP students in Tabriz University of Medical Sciences are not optimistic about the applicability of practical courses of basic medical sciences lessons

Effect of gibberellic acid on the quality of sperm and in vitro fertilization outcome in adult male rats

Gibberellic acid (GA3) is a group of plant hormones identified in various plants. The aim of this study was to determine the effects of GA3 on sperm parameters and in vitro fertilization (IVF). Fifty six adult male rats were divided into seven groups as, control, treatment and sham. Following 15, 30 and 45 days of GA3 and methanol alcohol (MA) administration, rats were euthanized and epididymis tail was transferred to human tubular fluid (HTF) medium containing 4 mg mL-1 bovine serum albumin (BSA) .Total number of sperms, the percentage of live sperms, immature sperms and sperms with damaged chromatin and IVF were examined. The oocytes were obtained from immature rats after the injection of pregnant mare's serum (PMSG) and human chorionic gonadotropin (HCG) hormones. Human tubular fluid was used as the fertilization medium and zygotes transferred to fresh 1-cell rat embryos culture medium (mR1ECM) to reach the blastocyst stage. This study showed that GA3 could decrease the number of total sperms on days 30 and 45 in treated group comparison with the control and sham groups. Additionally, GA3 increased the immature sperms and sperms with damaged chromatin. The percentage of fertilization, two-cell embryos and blastocyst resulting from the treatment group on days 30 and 45 also decreased and showed significant differences with the control and sham groups (p < 0.05). The results obtained from this study indicated that the oral use of GA3 could reduce the fertility in rats by influencing the sperm number and the quality of sperm’s chromatins

Connective Tissue Reaction to White and Gray MTA Mixed With Distilled Water or Chlorhexidine in Rats

INTRODUCTION: The purpose of this study was to compare the histocompatibility of white (WMTA) and gray (GMTA) mineral trioxide aggregate mixed with 0.12% chlorhexidine (CHX) and distilled water (DW) in subcutaneous connective tissues of rats. MATERIALS AND METHODS: The freshly mixed WMTA and GMTA with CHX or DW were inserted in polyethylene tubes and implanted into dorsal subcutaneous connective tissue of 50 Wistar Albino rats; tissue biopsies were collected and were then examined histologically 7, 15, 30, 60 and 90 days after the implantation procedure. The histology results were scored from 1-4; score 4 was considered as the worst finding. Data were analyzed using one-way ANOVA tests. RESULTS: All experimented materials were tolerated well by the connective tissues after 90-day evaluation, except for the WMTA/CHX group that had significantly more mean inflammatory scores (P&lt;0.001). There was a statistically significant difference in the mean inflammation grades between experimental groups in each interval (P&lt;0.001). After 90 days, GMTA/CHX group had the lowest inflammatory score. CONCLUSION: Although adding CHX to WMTA produces significantly higher inflammatory response, it seems a suitable substitute for DW in combination with GMTA. Further research is necessary to recommend this mixture for clinical use

The Effect of Low-Frequency Pulsed Electromagnetic Fields on the Differentiation of Permanent Dental Pulp Stem Cells into Odontoblasts

Introduction: Exposure to pulsed electromagnetic field (PEMF) has been revealed to affect the differentiation and proliferation of human mesenchymal stem cells derived from dental pulp multipotent stromal stem cells (DP-MSCs). This study aimed to investigate the differentiation effect of electromagnetic fields (EMFs) on the DP-MSC. Materials and Methods: PEMF was produced by a system comprising a multi-meter autotransformer, solenoid coils, and teslameter. This study included 10 groups of DP-MSCs which underwent different electromagnetic radiation time and beam intensity. Three samples tested for each group. The effect of PEMF with the intensity of 0.5 and 1 mT (mili Tesla) and 50 Hz on the proliferation rate of DP-MSC was evaluated at 20 and 40 minutes per day for seven days. MTT assay was applied to determine the growth and proliferation of DP-MSC. Gene expression of DMP1 for differentiation of DPSCs to odontoblasts was confirmed by Real Time PCR., ANOVA statistical analysis and Kruskal-Wallis test were used to analyze the data. Results: The survival in all exposure groups was significantly higher than that in control except in the group of 40 minutes, 1 mT (P&lt;0.05). In 20 minutes, 0.5 mT exposure, the survival intensity is significantly more than others (P&lt;0.05). In general, the intensity of survival was recorded, 20, 0.5 mT≥20, 1 mT≥40, 0.5 mT≥40, 1 mT respectively. Therefore, according to the obtained results, ELF-EMF increases the survival of cells except for one case (40 minutes, 1 mT), even though the effective underlying mechanisms in this process are still unclear. Conclusions: The results obtained promise that in the future, by placing an important part of the pulp next to the electromagnetic field, the lost part of the pulp can be reconstructed and the dentin barrier can be created

The Effect of Melatonin on Izumo1 Gene Expression, Sperm Motility and In Vitro Fertilization in Mice

Objective: IZUMO 1 is one of the most important and the most recent known proteins of sperm-oocyte fusion function. The present study aims to investigate the expression of IZUMO1 gene with melatonin injection in in-vitro conditions. Moreover, the sperm-oocyte fusion rate in in vitro fertilization (IVF) condition was examined. Materials and methods: In this study, 30 female and 45 male mice were divided into control and experimental groups. To investigate Izomo1 gene expression and sperm motility, 10 μM melatonin was added to the culture medium in the experimental group for 1 hour and to examine the fertilization rate 10 μM melatonin was added to culture medium in the experimental group for 1 hour. Then, sperms of the control and experimental groups were added to the oocyte collected and the fertilization was examined on embryo formation. Results: Examinations showed a significant increase in IZUMO1 gene expression and sperm motility in the experimental group (receiving melatonin) compared to the control group. Counting formed embryos showed that 83% of the oocytes have evolved to the fetus. Conclusion: We conclude that melatonin may be a good alternative for rising oocyte fertilization success by sperm in IV

Empagliflozin alleviates renal inflammation and oxidative stress in streptozotocin-induced diabetic rats partly by repressing HMGB1-TLR4 receptor axis

Objective(s): Empagliflozin, a sodium-glucose cotransporter-2 (SGLT-2) inhibitor, possesses verified anti-inflammatory and anti-oxidative stress effects against diabetic nephropathy. The present investigation aims to examine empagliflozin effects on the renal levels of high mobility group box-1 (HMGB1), a potent inflammatory cytokine, and its respective receptor toll-like receptor-4 (TLR-4) in STZ-induced diabetic rats.Materials and Methods: Empagliflozin at 10 mg/kg per os (p.o.) was administered for 4 weeks, starting 8 weeks after the induction of diabetes. Renal function, kidney inflammation, oxidative stress, and apoptosis markers as well as renal HMGB1, receptor for advanced glycation end products (RAGE), and TLR-4 levels were assessed.Results: In addition to down-regulating NF-κB activity in renal cortices, empagliflozin reduced renal levels of HMGB1, RAGE, and TLR-4. It alleviated renal inflammation as indicated by diminished renal expressions of inflammatory cytokines and chemokines like tumor necrosis factor-alpha (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) and also decreased urinary levels of interleukin-6 (IL-6) and alpha-1 acid glycoprotein (AGP). Moreover, empagliflozin ameliorated renal oxidative stress as demonstrated by decreased renal malondialdehyde (MDA) and elevated renal activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX). It also suppressed renal caspase-3, the marker of apoptosis; and furthermore, enhanced renal function noticed by the declined levels of serum urea and creatinine.Conclusion: These findings underline that empagliflozin is able to attenuate diabetes-related elevations in renal HMGB1 levels, an influential inflammatory cytokine released from the necrotic and activated cells, and its correspondent receptors, i.e., RAGE and TLR-4

Tangeretin protects renal tubular epithelial cells against experimental cisplatin toxicity

Objective(s): Cisplatin is an effective antineoplastic agent; its clinical utility, however, is limited by a few salient toxic side effects like nephrotoxicity. This study aimed to determine the potential protective effects of tangeretin, a citrus-derived flavonoid, against renal tubular cell injury in cisplatin-induced renal toxicity of rats.Materials and Methods: Tangeretin was injected intraperitoneally at 2.5 and 5 mg/kg doses for 10 days, and a single dose of cisplatin (8 mg/kg) was injected on the 7th day. Tests of kidney function and tubular injury in renal tissues and urine together with oxidative stress and inflammation markers were examined.Results: Tangeretin ameliorated cisplatin-induced elevations in serum creatinine, BUN, and histopathologic changes. It also attenuated kidney oxidative stress elicited by cisplatin as demonstrated by reduced MDA and increased GSH, CAT, and SOD activities, elevated Nrf2 expression and protein levels of its downstream effectors, HO-1 and NQO-1. Tangeretin further alleviated inflammation evoked by cisplatin as indicated by reduced NF-κB p65 subunit phosphorylation with a simultaneous decrement in its downstream effectors IL-1β and TNF-α expression and protein levels. Moreover, it declined caspase-3 protein levels and TUNEL positive cells in the kidneys, the markers of apoptosis and DNA fragmentation, thus improving renal endurance. Additionally, tangeretin mitigated renal levels of KIM-1 and NGAL, as well as urinary cystatin C and β2-microglobulin concentrations, the markers of renal tubular injury.Conclusion: Collectively, these data signify the binary profit of tangeretin: enhancement of renal protective mechanisms against cisplatin and attenuation of renal tubular cell injuries induced by the agent

Exosomes from Adipose Tissue-derived Mesenchymal Stem Cells Induce Regulatory T Cells in COVID‐19 Patients

An imbalance between regulatory T (Treg) and T-helper (Th)-17 cells has been implicated in the pathogenesis of coronavirus disease 2019 (COVID-19). Mesenchymal stem cells (MSCs) exert immunomodulatory properties through secreting exosomes. This study aimed to assess the effect of MSC-derived exosomes (MSC-Exo) on the differentiation of peripheral blood mononuclear cells (PBMCs) into  Tregs from patients with COVID-19. Exosomes were isolated from adipose tissue–derived MSCs. PBMCs were separated from the whole blood of COVID-19 patients (n=20). Treg frequency was assessed before and 48 hours after treatment of PBMCs with MSC-Exo using flow cytometry. Expression of FOXP3 and cytokine genes, and the concentration of cytokines associated with Tregs, were assessed before and after treatment with MSC-Exo. The frequency of CD4+CD25+CD127-  Tregs was significantly higher after treating PBMCs with MSC-Exo (6.695±2.528) compared to before treatment (4.981±2.068). The expressions of transforming growth factor (TGF)-β1, interleukin (IL)-10, and FOXP3 were significantly upregulated in MSC-Exo–treated PBMCs. The concentration of IL‐10 increased significantly after treatment (994.7±543.9 pg/mL) of PBMCs with MSC-Exo compared with before treatment (563.5±408.6 pg/mL). The concentration of TGF-β was significantly higher in the supernatant of PBMCs after treatment with MSC-Exo (477.0±391.1 pg/mL) than PBMCs before treatment (257.7±226.3 pg/mL). MSC-Exo has the potential to raise anti-inflammatory responses by induction of  Tregs, potentiating its therapeutic effects in COVID-19