Circulating microRNAs as novel biomarkers for measuring the potency of ginger extract against cyclophosphamide toxicity in rat renal tissues: molecular and histopathological study

OBJECTIVE

This study aims to explore underlying molecular variations in the expression of miRNAs in kidney tissues of ginger-treated and non-treated cyclophosphamide (CP)-intoxicated rats.

MATERIALS AND METHODS

  A total of 40 adult male Wistar rats were randomly divided into four groups of 10 each: Group I (control: received normal food and water), Group II (received ginger at a dose of 300 mg/kg), Group III (received CP 75 mg/kg, i.p.), and Group IV (received the same dose of CP and ginger extract).  Rats received a single injection of 75 mg/kg CP on days 3, 4, 5, 19, 20, and 21. In CP-intoxicated rats, the treatment with ginger extract at a dose of 300 mg/kg was received by oral gavage starting seven days before CP and continuing throughout the duration of the experiment for four weeks. Molecular variations in the expression of miRNAs, apoptotic genes, histological kidney damage, and abnormal kidney function in control, ginger, and CP-intoxicated rats were identified by using real-time RT-PCR Analysis, immunohistochemical, and colorimetric assays. In addition, HPLC analysis and liquid chromatography spectrophotometry analysis using Diphenyl-1-picrylhydrazyl (DPPH) radical, and Β-Carotene-linoleic acid reagents were applied respectively for in-vitro screening of phytoconstituents and antioxidant activity for ginger extract.

RESULTS

The kidney tissues of CP-intoxicated rats displayed an increase in lipid peroxidation marker malonaldehyde (MDA), DNA damage, and fibrosis markers like hyaluronic acid (HA) and hydroxyproline Hypx) with a decrease in the superoxide dismutase (SOD) and total antioxidant capacity (TAC). In addition, molecular expressions of mRNA fibrotic genes such as collagen, type 1, alpha 1 (COL1A1), and α-smooth muscle actin (αSMA). Molecular expressions of levels of B-cell lymphoma 2 (BCl-2) mRNA gene were down-regulated, and the expression of mRNA apoptotic; BCL2 associated X gene (Bax), caspase-3, Bax/BCl-2 ratio genes were significantly up-regulated respectively. Moreover, cellular oxidative genes, erythroid 2-related factor (Nrf2), and heme oxygenase-1 (HO-1) were down-regulated, respectively. The miR-155-5p, miR-34a-5p, miR-21-5p significantly increased while the miR-193b-3p, miR-455-3p, and miR-342-3p significantly decreased. Ginger also increased the expression of Nrf2, HO-1, and BCl-2 genes in the kidneys of rats induced with CP. In addition, active phytoconstituents, particularly 6]]-shogaol and 6]]-gingerol, were significantly identified in ginger extract using HPLC analysis. Antioxidant activity of these active metabolites were shown to be higher against in vitro free radicals (DPPH and Β-Carotene-linoleic acid), suggesting the potential antioxidant and antiapoptotic properties of ginger against CP-toxicity.

CONCLUSIONS

Treatment with ginger in rats induced with CP resulted in significant improvement in the expression of certain molecular miRNAs. The kidney tissues of these rats showed a marked decrease in the expression of miR-155-5p, miR-34a-5p, and miR-21-5p, while the levels of miR-193b-3p, miR-455-3p, and miR-342-3p were observed to increase significantly. In conclusion, ginger can protect rats from CP-induced nephrotoxicity.

Targeted Drug Administration onto Cancer Cells Using Hyaluronic Acid-Quercetin-Conjugated Silver Nanoparticles

Quercetin (QtN) displays low systemic bioavailability caused by poor water solubility and instability. Consequently, it exerts limited anticancer action in vivo. One solution to increase the anticancer efficacy of QtN is the use of appropriate functionalized nanocarriers that preferentially target and deliver the drug to the tumor location. Herein, a direct advanced method was designed to develop water-soluble hyaluronic acid (HA)-QtN-conjugated silver nanoparticles (AgNPs). HA-QtN reduced silver nitrate (AgNO₃) while acting as a stabilizing agent to produce AgNPs. Further, HA-QtN#AgNPs served as an anchor for folate/folic acid (FA) conjugated with polyethylene glycol (PEG). The resulting PEG-FA-HA-QtN#AgNPs (further abbreviated as PF/HA-QtN#AgNPs) were characterized both in vitro and ex vivo. Physical characterizations included UV-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), particle size (PS) and zeta potential (ZP) measurements, and biopharmaceutical evaluations. The biopharmaceutical evaluations included analyses of the cytotoxic effects on the HeLa and Caco-2 cancer cell lines using the MTT assay; cellular drug intake into cancer cells using flow cytometry and confocal microscopy; and blood compatibility using an automatic hematology analyzer, a diode array spectrophotometer, and an enzyme-linked immunosorbent assay (ELISA). The prepared hybrid delivery nanosystem was hemocompatible and more oncocytotoxic than the free, pure QtN. Therefore, PF/HA-QtN#AgNPs represent a smart nano-based drug delivery system (NDDS) and could be a promising oncotherapeutic option if the data are validated in vivo.

RhoA/ROCK inhibition attenuates endothelin-1-induced elevated glomerular permeability to albumin, inflammation, and fibrosis

Endothelin-1 (ET-1) contributes to the development of kidney diseases. However, the underlying molecular mechanism is largely undefined. Here we sought to investigate the potential role of ET-1 receptors, ET_A and ET_B in the regulation of increased glomerular permeability and underlying signaling pathways post-ET-1 infusion. Male Sprague-Dawley rats were infused with ET-1 (2 pmol/kg per minute, i.v.) for four weeks, and the effect on glomerular permeability to albumin (P_alb) and albuminuria was measured. The selective ROCK-1/2 inhibitor, Y-27632, was administered to a separate group of rats to determine its effect on ET-1-induced P_alb and albuminuria. The role of ET_A and ET_B receptors in regulating RhoA/ROCK activity was determined by incubating isolated glomeruli from normal rats with ET-1 and with selective ET_A and ET_B receptor antagonists. ET-1 infusion for four weeks significantly elevated P_alb and albuminuria. Y-27632 significantly reduced the elevation of P_alb and albuminuria. The activities of both RhoA and ROCK-1/2 were increased by ET-1 infusion. Selective ET_B receptor antagonism had no effect on the elevated activity of both RhoA and ROCK-1/2 enzymes. Selective ET_A receptor and combined ET_A/ET_B receptors blockade restored the activity of RhoA and ROCK-1/2 to normal levels. In addition, chronic ET-1 infusion increased the levels of glomerular inflammatory and fibrotic markers. These effects were all attenuated in rats following ROCK-1/2 inhibition. These observations suggest that ET-1 contributes to increased albuminuria, inflammation, and fibrosis by modulating the activity of the ET_A-RhoA/ROCK-1/2 pathway. Selective ET_A receptor blockade may represent a potential therapeutic strategy to limit glomerular injury and albuminuria in kidney disease.

Measuring the Effectiveness of Faculty Feedback on the use of an active integrated instructional pedagogy for the embryology course

Objectives

Didactic time-honoured teaching pedagogies carry a low educational impact due to their inability to foster active learning. Active participation from learners is considered to enhance their learning experience. Furthermore, constructive feedback has been found to facilitate active learning. This study aims to measure the impact of interventions via the use of active learning and feedback on the academic performance of medical students.

Methods

We conducted an observational multi-stage prospective study of the medical students undertaking embryology courses via passive learning (90 students), active integrated learning (80 students), and finally, with active learning and effective feedback (85 students) over three successive years. The students' grades in the formative and summative assessments were compared with their end-of-course grades. Additionally, the students’ perceptions about the courses were analysed using a self-constructed questionnaire.

Results

A total of 255 students participated in this research. The observed frequencies of the students’ responses showed significant variations in their responses to all the statements (X², p < 0.0001). There was a positive trend towards the interventions carried out via active learning as well as feedback. Students' active participation increased from 24% to 69%, and finally to 72% across three years. Furthermore, students were motivated to attend sessions, as can be seen in the participation rates of 28%, 70%, and 82%, respectively. There was a significant improvement in academic grades across the three years (p values of 0.000, 0.000, and 0.006, respectively).

Conclusion

This study validates the effectiveness of active learning and feedback on the academic performance of medical students. It is possible for an educational approach of active integrated learning followed by feedback to be embedded in the medical curricula.

Effectiveness of the team-based learning (TBL) strategy on medical students' performance

Objectives

Team-based learning (TBL) represents a new and interesting educational strategy. It helps to enhance students' professional competencies and ideally works to prepare them in their pursuit of lifelong learning. The aim of this study is to evaluate the effectiveness of TBL as an educational strategy on medical students' performance in a problem-based learning (PBL) curriculum.

Methods

A cross-sectional study was conducted through a self-designed questionnaire. It was constructed to examine several aspects of TBL, including cognition, social skills, high school educational system, and personal development. A total of 112 students were invited to participate in the study and 100 completed the survey. Individual-readiness assurance test (IRAT) and group-readiness assurance test (GRAT) scores were collected and the data were analysed and compared to the results of the final assessment using Statistical Package for the Social Sciences (SPSS).

Results

A total of 52 students (52%) described TBL as fostering a cooperative learning environment and 64 students (64%) found the materials to be easier to understand when discussed among themselves as a group. Compared to final examination results, there was a significant correlation (p = 0.0001) between IRAT performance and final exam score. In addition, there was a significant correlation between high school education system and IRAT score, where the best performance was observed among students coming from schools using the British curriculum.

Conclusions

The overall perception and attitude of students toward the TBL system was positive and promising. Nevertheless, there are some notes and areas of concern that must be re-examined and remedied to improve TBL as an educational tool.