Vanillylacetone attenuates cadmium chloride-induced hippocampal damage and memory loss through up-regulation of nuclear factor erythroid 2-related factor 2 gene and protein expression

JOURNAL/nrgr/04.03/01300535-202412000-00030/figure1/v/2024-04-08T165401Z/r/image-tiff Memory loss and dementia are major public health concerns with a substantial economic burden. Oxidative stress has been shown to play a crucial role in the pathophysiology of hippocampal damage-induced memory impairment. To investigate whether the antioxidant and anti-inflammatory compound vanillylacetone (zingerone) can protect against hippocampal damage and memory loss induced by cadmium chloride (CdCl2) administration in rats, we explored the potential involvement of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, which is known to modulate oxidative stress and inflammation. Sixty healthy male Wistar rats were divided into five groups: vehicle-treated (control), vanillylacetone, CdCl2, vanillylacetone + CdCl2, vanillylacetone + CdCl2 + brusatol (a selective pharmacological Nrf2 inhibitor) groups. Vanillylacetone effectively attenuated CdCl2-induced damage in the dental gyrus of the hippocampus and improved the memory function assessed by the Morris Water Maze test. Additionally, vanillylacetone markedly decreased the hippocampal tissue levels of inflammatory biomarkers (interleukin-6, tumor necrosis factor-α, intracellular cell adhesive molecules) and apoptosis biomarkers (Bax and cleaved caspase-3). The control and CdCl2-treated groups treated with vanillylacetone showed reduced generation of reactive oxygen species, decreased malondialdehyde levels, and increased superoxide dismutase and glutathione activities, along with significant elevation of nuclear Nrf2 mRNA and protein expression in hippocampal tissue. All the protective effects of vanillylacetone were substantially blocked by the co-administration of brusatol (a selective Nrf2 inhibitor). Vanillylacetone mitigated hippocampal damage and memory loss induced by CdCl2, at least in part, by activating the nuclear transcription factor Nrf2. Additionally, vanillylacetone exerted its potent antioxidant and anti-inflammatory actions.

Defects oriented hydrothermal synthesis of TiO2 and MnTiO2 nanoparticles as photocatalysts for wastewater treatment and antibacterial applications

Pure and manganese-doped titanium dioxide nanoparticles (MnTiO2-NPs) were synthesized by the defect-oriented hydrothermal approach. The synthesized material was then characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), and UV-visible spectroscopy (UV-Vis). The agar well diffusion method assessed the antibacterial efficiency of TiO2 and MnTiO2-NPs against E. coli and S. aureus. Zone of inhibition (ZOI) formed by pure TiO2 was observed as 12 mm and 11.5 mm against E. coli and S. aureus, while for MnTiO2-NPs it was observed as 19 mm (E. coli) and 21 mm (S. aureus). The concentration of synthesized nanoparticles (10 mg/ml, and 20 mg/ml) was used for antibacterial studies. The efficacy of the pure and MnTiO2-NPs as an active photocatalyst for the degradation of methylene blue (MB) dye was also assessed using a UV light. It was observed that the photodegradation efficiency of 1 g of MnTiO2-NPs was higher than the same amount of pure TiO2. The results suggest that the photocatalyst concentration directly impacts the photodegradation of MB dye. The pH value was found to influence the photodegradation of MB dye at higher pH values. Based on the obtained results, MnTiO2-NPs were observed as a promising agent for microbial resistance and water remediation.

Forced Swimming-Induced Depressive-like Behavior and Anxiety Are Reduced by Chlorpheniramine via Suppression of Oxidative and Inflammatory Mediators and Activating the Nrf2-BDNF Signaling Pathway

The first-generation antihistamine chlorpheniramine (CPA) is believed to have both anxiolytic and antidepressant properties. The current study sought to assess the mechanisms behind the antidepressant and anxiolytic effects of CPA therapy concerning oxidative stress, inflammation, and nuclear factor p45 for erythroid 2-Brain-derived neurotrophic factor (Nrf2-BDNF) signaling pathway in forced swimming-induced depressive-like behavior and anxiety. Eighteen male Wistar rats (180-200 gm) rats were separated into three groups (n = 6): a stressed group (acute stress) that underwent the forced swimming test (FST) and a stressed group that received pretreatment with CPA (10 mg/kg body weight) for 3 weeks (CPA + acute stress). Animals were subsequently put through the following behavioral tests after undergoing a forced swim test (FST) for 5 min: an immobility test, open field test, and elevated plus maze test. Serum cortisol levels were measured when the rats were euthanized at the end of the experiments. Brain neurotransmitters (cortisol, serotonin, and noradrenaline), oxidative stress (SOD and MDA), inflammatory (IL-6 and IL-1) biomarkers, and the Nrf2-BDNF signaling pathway in the hippocampus and cerebral cortex tissues was determined. CPA prevented stress-induced increases in cortisol levels (p < 0.0001), decreased brain neurotransmitters, and increased oxidative stress and inflammation. CPA also upregulated the Nrf2-BDNF signaling pathway. Thus, CPA mitigates depressive-like behavior and anxiety by inhibiting oxidative stress and inflammation and upregulating the Nrf2-BDNF signaling pathway in the brain tissues.

Impact of glycogen synthase kinase-3ß inhibition on rats' temporomandibular joint collagen-induced rheumatoid arthritis with correlation to miRNA-155/miRNA-24 expression

OBJECTIVE

The current study considered assessing the role of miRNA-155 and miRNA-24 in collagen-induced rheumatoid arthritis (RA) in rats' temporomandibular joint (TMJ). Their role in histological aggressiveness of the disease and therapy response to glycogen synthase kinase (GSK) inhibitor 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8) will be studied.

MATERIALS AND METHODS

Rats were randomly distributed to four groups (8 rats/group): group I negative control, group II collagen-induced rheumatoid arthritis (CIA), group III Control+TDZD-8 treated group, and group IV CIA+TDZD-8 treated group. Then were euthanized 42 days after the start of the experiment. H&E staining, Masson trichrome staining, and immunohistochemical antibodies against S100 were performed. qRT-PCR of miRNA-155 and miRNA-24 were done for frozen synovial tissues.

RESULTS

Histological analysis showed that the most affected structure in induced rheumatoid arthritis of TMJ is the articular disc, condylar head, and subchondral bone. Combined treatment with TDZD-8 improved histological status in the joint. Masson's trichrome (MTC) histochemical staining revealed disarrangement of collagen fibers and adherence between the articular disc and condylar cartilage. Meanwhile, the morphology and collagen composition of the disc and condyle in CIA+ TDZD-8 were similar to those of healthy tissues. Immunohistochemical analysis for S100A4 revealed increased immunoreactivity staining in the CIA group. The immunoreactivity was significantly decreased in CIA+ TDZD-8 treated group. TDZD-8 significantly decreased the levels of miRNA-155 and miRNA-24 in synovial tissue.

CONCLUSIONS

Our results reveal for the first-time correlation of miRNA-155 and miRNA-24 that might be implicated in the onset of TMJ RA. Consequently, the treatment of CIA with GSK inhibitor (TDZD-8) yields encouraging results. We predicted the TDZD-8 might protect against CIA by suppressing miRNA-155, miRNA-24, and S100A4 protein levels.

Design, synthesis, and docking of novel thiazolidine-2,4-dione multitarget scaffold as new approach for cancer treatment

Novel thiazolidine-2,4-diones have been developed and estimated as conjoint inhibitors of EGFR^T790M and VEGFR-2 against HCT-116, MCF-7, A549, and HepG2 cells. Compounds 6a, 6b, and 6c were known to be the dominant advantageous congeners against HCT116 (IC₅₀  = 15.22, 8.65, and 8.80 µM), A549 (IC₅₀  = 7.10, 6.55, and 8.11 µM), MCF-7 (IC₅₀  = 14.56, 6.65, and 7.09 µM) and HepG2 (IC₅₀  = 11.90, 5.35, and 5.60 µM) mass cell lines, correspondingly. Although compounds 6a, 6b, and 6c disclosed poorer effects than sorafenib (IC₅₀  = 4.00, 4.04, 5.58, and 5.05 µM) against the tested cell sets, congeners 6b and 6c demonstrated higher actions than erlotinib (IC₅₀  = 7.73, 5.49, 8.20, and 13.91 µM) against HCT116, MCF-7 and HepG2 cells, yet lesser performance on A549 cells. The hugely effective derivatives 4e-i and 6a-c were inspected versus VERO normal cell strains. Compounds 6b, 6c, 6a, and 4i were found to be the most effective derivatives, which suppressed VEGFR-2 by IC₅₀  = 0.85, 0.90, 1.50, and 1.80 µM, respectively. Moreover, compounds 6b, 6a, 6c, and 6i could interfere with the EGFR^T790M performing strongest effects with IC₅₀  = 0.30, 0.35, 0.50, and 1.00 µM, respectively. What is more, 6a, 6b, and 6c represented satisfactory in silico computed ADMET profile.

Lower Extremity Arterial Disease in Type 2 Diabetes Mellitus: Metformin Inhibits Femoral Artery Ultrastructural Alterations as well as Vascular Tissue Levels of AGEs/ET-1 Axis-Mediated Inflammation and Modulation of Vascular iNOS and eNOS Expression

Lower extremity arterial disease (LEAD) is a major risk factor for amputation in diabetic patients. The advanced glycation end products (AGEs)/endothelin-1 (ET-1)/nitric oxide synthase (NOS) axis-mediated femoral artery injury with and without metformin has not been previously investigated. Type 2 diabetes mellitus (T2DM) was established in rats, with another group of rats treated for two weeks with 200 mg/kg metformin, before being induced with T2DM. The latter cohort were continued on metformin until they were sacrificed at week 12. Femoral artery injury was established in the diabetic group as demonstrated by substantial alterations to the femoral artery ultrastructure, which importantly were ameliorated by metformin. In addition, diabetes caused a significant (p < 0.0001) upregulation of vascular tissue levels of AGEs, ET-1, and iNOS, as well as high blood levels of glycated haemoglobin, TNF-α, and dyslipidemia. All of these parameters were also significantly inhibited by metformin. Moreover, metformin treatment augmented arterial eNOS expression which had been inhibited by diabetes progression. Furthermore, a significant correlation was observed between femoral artery endothelial tissue damage and glycemia, AGEs, ET-1, TNF-α, and dyslipidemia. Thus, in a rat model of T2DM-induced LEAD, an association between femoral artery tissue damage and the AGEs/ET-1/inflammation/NOS/dyslipidemia axis was demonstrated, with metformin treatment demonstrating beneficial vascular protective effects.

Suppression of knee joint osteoarthritis induced secondary to type 2 diabetes mellitus in rats by resveratrol: role of glycated haemoglobin and hyperlipidaemia and biomarkers of inflammation and oxidative stress

Background: We investigated whether the anti-inflammatory and antioxidant agent, resveratrol can inhibit type 2 diabetes mellitus (T2DM)-induced osteoarthritis (OA) in rats and whether it is associated with the suppression of glycaemia, dyslipidemia and inflammatory and oxidative stress biomarkers.Materials and methods: T2DM was induced by streptozotocin (50 mg/kg body weight) and high carbohydrate and fat diet (HCFD). The protective group was put on resveratrol (30 mg/kg) 14 days prior to the induction of diabetes and continued on resveratrol and HCFD until being sacrificed at week 12.Results: Diabetic rats showed a substantial damage to the knee joints and loss of proteoglycans from the articular cartilage, which were effectively but not completly protected by resveratrol. Resveratrol also significantly (p ≤ .0029) reduced diabetic up-regulation of HbA1c, hyperlipidaemia, inflammation and oxidative stress.Conclusions: Resveratrol protects against T2DM-induced OA associated with the inhibition of glycated haemoglobin, dyslipidemia, and biomarkers of oxidative stress and inflammation.

Metformin Is Associated with the Inhibition of Renal Artery AT1R/ET-1/iNOS Axis in a Rat Model of Diabetic Nephropathy with Suppression of Inflammation and Oxidative Stress and Kidney Injury

Diabetes is the most common cause of end-stage renal disease, also called kidney failure. The link between the renal artery receptor angiotensin II type I (AT1R) and endothelin-1 (ET-1), involved in vasoconstriction, oxidative stress, inflammation and kidney fibrosis (collagen) in diabetes-induced nephropathy with and without metformin incorporation has not been previously studied. Diabetes (type 2) was induced in rats and another group started metformin (200 mg/kg) treatment 2 weeks prior to the induction of diabetes and continued on metformin until being culled at week 12. Diabetes significantly (p < 0.0001) modulated renal artery tissue levels of AT1R, ET-1, inducible nitric oxide synthase (iNOS), endothelial NOS (eNOS), and the advanced glycation end products that were protected by metformin. In addition, diabetes-induced inflammation, oxidative stress, hypertension, ketonuria, mesangial matrix expansion, and kidney collagen were significantly reduced by metformin. A significant correlation between the AT1R/ET-1/iNOS axis, inflammation, fibrosis and glycemia was observed. Thus, diabetes is associated with the augmentation of the renal artery AT1R/ET-1/iNOS axis as well as renal injury and hypertension while being protected by metformin.

Association of resveratrol with the suppression of TNF-α/NF-kB/iNOS/HIF-1α axis-mediated fibrosis and systemic hypertension in thioacetamide-induced liver injury

Chronic liver injury can lead to hepatic failure and the only available method of treatment would be liver transplantation. The link between inflammation (TNF-α), nuclear factor-kappa B (NF-kB), nitrosative stress (iNOS) and hypoxia-inducible factor-1α (HIF-1α) in thioacetamide (TAA) induced liver fibrosis, and hypertension with and without the incorporation of the anti-inflammatory and antioxidant resveratrol (RES) has not been investigated before. Consequently, we injected rats with either 200 mg/kg TAA for 8 weeks starting at week 2 (model group) or pretreated them before TAA injections with RES (20 mg/kg) for 2 weeks and continued them on RES and TAA until being culled at week 10 (protective group). In the model group, we documented the induction of hepatic fibrosis and upregulation of tumor necrosis factor-α (TNF-α), NF-kB, inducible nitric oxide synthase (iNOS), HIF-1α and the profibrotic biomarkers alpha-smooth muscle actin (α-SMA) and matrix metalloproteinase-9 (MMP-9) that was significantly (p ≤ 0.0014) ameliorated by RES. RES also significantly (p ≤ 0.0232) reduced triglycerides (TG), cholesterol (CHOL), very low-density lipoprotein (vLDL-C), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure, and heart rate (HR) induction by TAA. Also, a significant (p < 0.0001) positive correlation between TNF-α/NF-kB/iNOS/HIF-1α axis-mediated fibrosis and hypertension and liver injury biomarkers was observed. These findings suggest that in the hepatotoxic compound, TAA is associated with TNF-α/NF-kB/iNOS/HIF-1α-mediated fibrosis and hypertension, whilst being inhibited by RES.

An Ideal Approach for Enhancing 5-Fluorouracil Anticancer Efficacy by Nanoemulsion for Cytotoxicity against a Human Hepatoma Cell Line (HepG2 Cells)

The core objectives of the research were to prepare 5-fluorouracil nanoemulsion (FU-NE) and to evaluate the physiochemical properties and to study the in vitro antiproliferation in HepG2 cell lines. The physiochemical parameters determined were compatibility, particle size (PS), polydispersity index (PDI), zeta potential (ZP), density, surface tension (ST), pH, viscosity, in vitro release of FU, cytotoxicity, and apoptosis study. The prepared FU-NE3 was stable, sterile, and homogeneous. On the HepG2 (120 μg.mL-1) cells, in vitro cytotoxicity was obtained at IC50 concentration. Apoptosis examination by AO/EBand Hoechst staining shows that the majority of cell demise was caused by apoptosis, with a tiny fraction of necrosis. Hence, this investigation concluded that the developed FU-NE has now desirable characteristics for drug delivery to the cancer cell and may be screened for the in vivo colorectal anticancer activity.

Inhibition of glycogen synthase kinase-3β protects against collagen type II-induced arthritis associated with the inhibition of miR155/24 and inflammation and upregulation of apoptosis in rats

MicroRNAs have been implicated in the pathogenesis of rheumatoid arthritis (RA) and their syntheses are modulated by glycogen synthase kinase-3β (GSK-3β). Therefore, we hypothesised that the GSK-3β inhibitor, TDZD-8 can protect against collagen-induced arthritis (CIA) via downregulating miR155 and miR-24 expression. Rats were randomly allocated into four groups (n = 6) as follows: Control, Control + TDZD-8 (1 mg/kg), CIA, and CIA + TDZD-8. Rats were sacrificed after 6 weeks. We observed in the model group (CIA) significant (p<.05) increase in arthritis score and serum levels of RA biomarkers, which were significantly (p < .05) inhibited by TDZD-8. TDZD-8 also significantly (p<.05) inhibited CIA-induced synovial tissue levels of miR155, miR-24, and inflammation. In addition, a significant (p<.05) modulation of biomarkers of survival (Bcl-2) and apoptosis (cleaved caspase-3) by TDZD-8 was observed. Thus, TDZD-8 protects against CIA in rats for a period of 6 weeks, which is associated with the inhibition of miR155/24 and inflammation, and apoptosis augmentation.

Antioxidant Activity of Vitamin C against LPS-Induced Septic Cardiomyopathy by Down-Regulation of Oxidative Stress and Inflammation

In severe cases of sepsis, endotoxin-induced cardiomyopathy can cause major damage to the heart. This study was designed to see if Vitamin C (Vit C) could prevent lipopolysaccharide-induced heart damage. Eighteen Sprague Dawley male rats (n = 6) were divided into three groups. Rats received 0.5 mL saline by oral gavage in addition to a standard diet (Control group), rats received one dose of endotoxin on day 15 (lipopolysaccharide) (LPS) (6 mg/kg), which produced endotoxemia (Endotoxin group), and rats that received 500 mg/Kg BW of Vit C by oral gavage for 15 days before LPS administration (Endotoxin plus Vit C group). In all groups, blood and tissue samples were collected on day 15, six hours after LPS administration, for histopathological and biochemical analysis. The LPS injection lowered superoxide dismutase (SOD) levels and increased malondialdehyde in tissues compared with a control group. Furthermore, the endotoxin group showed elevated inflammatory biomarkers, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Both light and electron microscopy showed that the endotoxic-treated group’s cardiomyocytes, intercalated disks, mitochondria, and endothelial cells were damaged. In endotoxemic rats, Vit C pretreatment significantly reduced MDA levels and restored SOD activity, minimized biomarkers of inflammation, and mitigated cardiomyocyte damage. In conclusion: Vit C protects against endotoxin-induced cardiomyopathy by inhibiting oxidative stress cytokines.

Intermittent Short-Duration Re-oxygenation Attenuates Cardiac Changes in Response to Hypoxia: Histological, Ultrastructural and Oxidant/Antioxidant Parameters

Context: Intermittent short-duration re-oxygenation attenuates cardiac changes in response to hypoxia.

Objective: To see if intermittent short-duration re-oxygenation may protect the heart muscle from hypoxia damage.

Materials and Methods: Eighteen albino rats were used to carry out the study. Rats divided into: (normoxia); rats exposed to room air as a control, second (hypoxic) group; rats subjected to a pressure of 405 mmHg in a hypobaric chamber to simulate hypoxia at 5,000 m, and third (intermittent short-duration re-oxygenation); rats exposed to room air three times per day. Experiments were all 14 days long.

Results: Hypoxia enhanced the oxidative stress biomarker malondialdehyde while lowering the antioxidant superoxide dismutase . The levels of tumour necrosis factor (TNF-α) and interleukin-6 (IL-6) in the myocardium were elevated in hypoxic hearts. The hypoxic rats’ cardiac myofibrils showed disarray of muscle fibres, vacuolation of the sarcoplasm, pyknosis of the nucleus, and expansion of intercellular gaps on histological examination. In addition, cardiomyocytes showed degenerative defects in ventricular myocardial cells on ultrastructural analysis. Myofibril thinning and degenerative mitochondrial changes affected intercalated discs with fascia adherent, desmosomes, and gap junction. Intermittent short-duration re-oxygenation improve cardiac histological, ultrastructural and oxidant/antioxidant parameters changes during hypoxia.

Conclusion: Hypoxia showed a substantial impact on myocardial architecture, as well as increased oxidative stress and pro-inflammatory cytokines. Intermittent short-duration re-oxygenation significantly decreases hypoxia-induced cardiac changes.

Potential Protective Effect of Vitamin C on Qunalphos-Induced Cardiac Toxicity: Histological and Tissue Biomarker Assay

Insecticides and toxicants abound in nature, posing a health risk to humans. Concurrent exposure to many environmental contaminants has been demonstrated to harm myocardial performance and reduce cardiac oxidative stress. The purpose of this research was to study the protective effect of vitamin C (Vit C) on quinalphos (QP)-induced cardiac tissue damage in rats. Eighteen albino male rats were randomly categorised into three groups (n = 6). Control, QP group: rats received distilled water. QP insecticide treatment: an oral administration of QP incorporated in drinking water. QP + Vit C group: rats received QP and Vit C. All the experiments were conducted for ten days. Decline of cardiac antioxidant biomarkers catalase (CAT) and reduced glutathione (GPx) along with increased proinflammatory markers tumour necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) indicated oxidative and inflammatory damage to the heart following administration of QP when compared to control rats. The light microscopic and ultrastructure appearance of QP-treated cardiomyocytes exhibited cardiac damage. Administration of Vit C showed decreased oxidative and inflammatory biomarkers, confirmed with histological and electron microscopic examination. In conclusion, Vit C protected the heart from QP-induced cardiac damage due to decreased inflammation and oxidative stress.

Metformin ameliorates ROS-p53-collagen axis of fibrosis and dyslipidemia in type 2 diabetes mellitus-induced left ventricular injury

BACKGROUND

The link between oxidative stress (ROS), apoptosis (p53) and fibrosis (collagen) in type 2 diabetes mellitus (T2DM)-induced cardiac injury in the presence and absence of the antidiabetic drug, metformin has not been investigated before.

MATERIAL AND METHODS

T2DM was induced in rats by a combination of high carbohydrate and fat diets (HCFD) and streptozotocin (50 mg/kg) injection. The protection group started metformin (200 mg/kg) treatment 14 days prior to the induction of diabetes and continued on metformin and HCFD until being sacrificed at week 12.

RESULTS

Diabetes significantly induced blood levels of ROS and left ventricular p53 and collagen expression that was inhibited by metformin. Metformin also significantly reduced glycated haemoglobin and dyslipidemia induced by diabetes. In addition, a significant correlation between ROS-p53-collagen axis and glycaemia and hyperlipidaemia was observed.

CONCLUSIONS

These findings show that metformin provides substantial protection against diabetic cardiomyopathy-induced ROS-p53 mediated fibrosis and dyslipidemia.

Relation between resistin, PPAR-γ, obesity and atherosclerosis in male albino rats

Obesity and atherosclerosis are inflammatory states involving variable metabolic signals. The adipokine resistin is implicated in adipose tissue dysfunction and is modulated by PPARγ. In this study, resistin and PPARγ role is investigated in the development of CVS disease. Forty-eight Adult male albino rats were divided into control, obesity and atherosclerotic groups; each group is divided into two subgroups; with and without PPARγ agonist administration for 8 weeks. To assess pathological changes; lipid profile, inflammatory mediator, serum resistin level and resistin expression in adipose tissue were measured. Aorta is histopathologically evaluated. It was found that resistin expression is significantly correlated with lipid profile and inflammatory status in obesity and atherosclerotic groups, and PPARγ agonist administration significantly improves inflammatory status and dyslipidemic profile across studied groups (p < .05). Aortic wall shows histopathological evidence of atherosclerosis in obesity group which is more evident in atherosclerotic group, and milder changes upon receiving PPARγ agonist.

Simulation-Based Learning Versus Didactic Lecture in Teaching Bronchial Asthma for Undergraduate Medical Students: a Step Toward Improvement of Clinical Competencies

BACKGROUND

Simulation-based learning (SBL), an effective teaching strategy, is still questionable on whether it can be an alternative to didactic lectures in medical education. Our study aimed to evaluate the effectiveness of SBL versus traditional lectures in retention of knowledge.

METHODS

A randomized controlled trial was conducted among medical students who were divided in two groups (36 students each). Each group received the same information about diagnosis and management of bronchial asthma, but with a different teaching method: didactic lecture or simulation. Knowledge level was tested before, immediately after the teaching sessions and 3 months later using multiple-choice questions. Student's satisfaction was evaluated using feedback questionnaire.

RESULTS

The simulation group scored higher than the lecture group in the post-test and the late test. However, these differences were not significant. Additionally, students' satisfaction scores were significantly higher in the simulation group than in the lecture group (p < 0.01). Students ranked simulation significantly better regarding motivation (71.9%), comfort (59.4%), understanding (59.4%), and effective communication (59.4%) (p < 0.01).

CONCLUSION

Simulation is as effective as lecture in retention of medical knowledge. Nonetheless, students agree that it is more satisfactory and interesting. SBL integration in medical programs is recommended to overcome obstacles in clinical training.

Suppression of type 2 diabetes mellitus-induced aortic ultrastructural alterations in rats by insulin: an association of vascular injury biomarkers

Diabetes represents a major public health problem and an estimated 70% of people with diabetes die of cardiovascular complications. The protective effect of insulin treatment against ultrastructural damage to the tunica intima and tunica media of the aorta induced by type 2 diabetes mellitus (T2DM) has not been investigated before using transmission electron microscopy (TEM). Therefore, we induced T2DM in rats using high fat diet and streptozotocin (50 mg/kg) and administered insulin daily by i.v injection for 8 weeks to the treatment group. Whereas, the T2DM control group were left untreated for the duration of the experiment. A comparison was also made between the effect of insulin on aortic tissue and the blood level of biomarkers of vascular injury, inflammation, and oxidative stress. T2DM induced profound ultrastructural damage to the aortic endothelium and vascular smooth muscle cells, which were substantially protected with insulin. Furthermore, insulin returned blood sugar to a control level and significantly (p < .05) inhibited diabetic up-regulation of endothelial and leukocyte intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion protein 1 (VCAM-1), endothelial cell adhesion molecules, P-selectin and E-selectin, tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), and malondialdehyde (MDA). Furthermore, insulin augmented the blood level of the anti-oxidant enzyme superoxide dismutase (SOD). We conclude that in a rat model of T2DM, insulin treatment substantially reduces aortic injury secondary to T2DM for a period of 8 weeks, possibly due to the inhibition of hyperglycemia, vascular activation, inflammation, and oxidative stress.

Metformin pretreatment suppresses alterations to the articular cartilage ultrastructure and knee joint tissue damage secondary to type 2 diabetes mellitus in rats

Osteoarthritis (OA) secondary to diabetes affects millions of people worldwide and can lead to disability. The protective effect of metformin pretreatment against alterations to the articular cartilage ultrastructure induced by type 2 diabetes mellitus (T2DM) associated with the inhibition of oxidative stress and inflammation has not been investigated before. Therefore, we induced T2DM in rats (the model group) using high carbohydrate and fat diet and a single injection of streptozotocin (50 mg/kg body weight). The protective group of rats started metformin (200 mg/kg body weight) treatment 14 days before diabetic induction and continued on metformin until the end of the experiment at week 12. Harvested tissues obtained from knee joints were prepared for staining with hematoxylin and eosin (H&E), safranin o staining, and electron microscopy. Histology images showed that OA was developed in the T2DM rats as demonstrated by a substantial damage to the articular cartilage and profound chondrocyte and territorial matrix ultrastructural alterations, which were partially protected by metformin. In addition, metformin significantly (p < .05) reduced hyperglycemia, glycated hemoglobin (HbA1 c), malondialdehyde (MDA), high sensitivity C-reactive protein (hs-CRP), and interleukin-6 blood levels induced by diabetes. Furthermore, a significant (p ≤ 0.015) correlation between either OA cartilage grade score or the thickness of the articular cartilage and the blood levels of HbA1 c, hs-CRP, MDA, superoxide dismutase (SOD) were observed. These findings demonstrate effective protection of the articular cartilage by metformin against damage induced secondary to T2DM in rats, possibly due to the inhibition of hyperglycemia and biomarkers of oxidative stress and inflammation.

Inhibition of GSK3β protects against collagen type II-induced arthritis associated with a decrease in synovial leukocyte infiltration and inhibition of endoplasmic reticulum stress and autophagy biomarkers

We sought to determine whether TDZD-8, the inhibitor of the glycogen synthase kinase-3β (GSK3β), can protect the synovial membrane of the knee joint against injuries induced by collagen type II immunization (CIA) possibly via the downregulation of synovial leukocyte infiltration, endoplasmic reticulum stress (ERS), and autophagy. The model group of rats (CIA) were immunized over a period of 3 weeks with collagen type II, whereas the treated group of rats (CIA + TDZD-8) were treated with TDZD-8 (1 mg/kg) for 21 days after the completion of the immunization regimen. All rats were then killed at week 6. Harvested synovial tissues were prepared for immunohistochemistry staining, and synovial homogenates were assayed for biomarkers of ERS, autophagy, apoptosis, and cell survival and proliferation. In addition, blood samples were assayed for biomarkers of arthritis. Synovial tissue images showed that CIA enhanced leukocyte recruitment as demonstrated by an increased CD45+ (leukocyte common antigen) immunostaining, which was markedly decreased by TDZD-8. TDZD-8 also significantly (P < .05) inhibited collagen-induced autophagy biomarkers Beclin-1 and LC3II, the ERS biomarkers GRP-78, IRE1-α, XBPIs, and eIF2a, and the survival protein Bcl-2. Whereas, the collagen-induced proliferative biomarkers Akt and mTOR were not inhibited by TDZD-8, and CIA inhibited the apoptotic proteins CHOP and cleaved caspase-3, which were augmented by TDZD-8. We further demonstrated a significant (P < .05) correlation between autoantibodies generated during the course of arthritis and biomarkers of ERS and autophagy. We conclude that TDZD-8 inhibits CIA and decreases synovial leukocyte infiltration, ERS, and autophagy, which is independent of Akt/mTOR signalling.

Suppression of glomerular damage and apoptosis and biomarkers of acute kidney injury induced by acetaminophen toxicity using a combination of resveratrol and quercetin

Acute renal failure induced by a toxic dose of acetaminophen (also known as paracetamol, or APAP) is common in both humans and experimental animal models. Glomerular ultrastructural alterations induced by APAP overdose associated with the suppression of biomarkers of kidney injury have not been investigated before. Also, we investigated whether the combined polyphenolic antioxidants and anti-inflammatory compounds, resveratrol (RES) and quercetin (QUR) can protect against APAP-induced nephrotoxicity. Rats either received a single dose of APAP (2 g/kg) before being sacrificed after 24 hours or were pretreated for 7 days with combined doses of RES (30 mg/kg) and QUR (50 mg/kg) before being given a single dose of APAP and then sacrificed 24 hours post APAP ingestion. APAP significantly (p < 0.05) increased blood levels of urea, creatinine, malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), which were effectively reduced by RES + QUR. In addition, APAP overdose induced the tissue expression of the apoptotic biomarker, p53, and caused profound kidney damage as demonstrated by substantial alterations to the glomerular basement membrane, podocytes, endothelial cells, widening of Bowman's space, and vacuolation of the cells lining the parietal layer, which were substantially protected by RES + QUR. Furthermore, a significant (p < 0.0001) positive correlation was observed between either glomerular basement membrane or podocyte foot processes and these parameters, urea, creatinine, MDA, and TNF-α. Thus, we conclude that APAP induces alterations to the glomerulus ultrastructure, which is protected by resveratrol plus quercetin, which also reduces blood levels of urea and creatinine, and biomarkers of oxidative stress and inflammation.

Cross-talk between apelin and vasopressin in response to different osmotic stimuli in type 2 diabetic rats

Apelin, a peptide hormone that has been linked to insulin resistance, obesity and glucose metabolism, coexists with arginine vasopressin (AVP) in hypothalamic magnocellular neurons that control body fluid homeostasis. The significant correlation between serum glucose and serum osmolarity in uncontrolled DM indicates the need for adequate compensation, but how apelin and AVP contribute to this is still unsettled. This study aims to investigate the interaction between apelin and AVP in osmotic regulation in type 2 diabetes mellitus (T2DM), and to explore the underlying mechanism. Forty-eight adult male albino rats were divided into six groups: control (isotonic, ip 0.9% NaCl; hypotonic, ip distilled water; hypertonic, ip 2% NaCl) groups and T2DM (isotonic, hypotonic, hypertonic) groups. Serum levels of AVP, apelin, Na, glucose, serum and urine osmolarity were measured; kidney samples were taken for Aquaporin 2 channels (AQP2) and epithelial sodium channel gamma subunit (ENaCγ) gene expression. Hypothalamic tissue sections were used for immunohistochemical staining of apelin and AVP. Both in control and diabetic groups serum apelin, showed a significant negative correlation with serum AVP (r=-0.533, p≤ 0.001). Serum apelin and AVP were inversely proportional to their hypothalamic protein expression. Serum apelin and AVP were significantly higher in diabetic rats (P= 0.001) yet their percentage change in response to hypo and hyper-osmotic stimuli (1.5±0.7, -0.34±0.15 and -0.38±0.13, 1.95±0.36, respectively) was less pronounced when compared to control rats (3.28±0.52, -0.59±0.12 and -0.45±0.13, 2.58±0.93, respectively). Na and ENaCγ levels significantly increased in hypertonic rats, while AQP2 gene expression significantly increased in hypotonic rats. Both apelin and AVP reacted to osmotic stimuli in T2DM but with less sensitivity than in control rats. In spite of its abnormal increased levels in diabetic rats, apelin maintained its role through counteracting AVP action.