Wharton's jelly mesenchymal stem cells attenuate global hypoxia-induced learning and memory impairment via preventing blood-brain barrier breakdown.

Objectives: Intracerebroventricular (ICV) injections of mesenchymal stem cells (MSCs) may improve the function and structure of blood-brain barrier (BBB), possibly by preserving the BBB integrity. This study examined the impact of Wharton's jelly (WJ)-MSCs on cognitive dysfunction and BBB disruption following a protracted hypoxic state. Materials and Methods: Twenty-four male Wistar rats were randomly studied in four groups: Control (Co): Healthy animals, Sham (Sh): Rats were placed in the cage without hypoxia induction and with ICV injection of vehicle, Hypoxic (Hx)+vehicle: Hypoxic rats with ICV injection of vehicle (5 µl of PBS), and Hx+MSCs: Hypoxic rats with ICV injection of MSCs. Spatial learning and memory were evaluated one week after WJ-MSCs injection, and then animals were sacrificed for molecular research. Results: Hypoxia increased latency and lowered the time and distance required reaching the target quarter, according to the findings. Furthermore, hypoxic rats had lower gene expression and protein levels of hippocampus vascular endothelial (VE)-cadherin, claudin 5, and tricellulin gene expression than Co and Sh animals (P<0.05). Finally, administering WJ-MSCs after long-term hypoxia effectively reversed the cognitive deficits and prevented the BBB breakdown via the upregulation of VE-cadherin, claudin 5, and tricellulin genes (P<0.05). Conclusion: These findings suggest that prolonged hypoxia induces spatial learning and memory dysfunction and increases BBB disruption, the potential mechanism of which might be via reducing VE-cadherin, claudin 5, and tricellulin genes. Hence, appropriate treatment with WJ-MSCs could reverse ischemia adverse effects and protect the BBB integrity following prolonged hypoxia.

Teaching professionalism in cadaver dissection: medical students' perspective.

This study was designed to facilitate freshman medical students' adaptation to the dissection room and familiarize them with the related ethical codes. Single-group post-test design research was conducted at Tehran University of Medical Sciences in 2018 - 2019. The program began with a brief explanation of the necessity of the subject, and after a documentary film was shown, the principles of professional and ethical behaviors in the dissection room were discussed by a panel of experts. In the end, a valid and reliable evaluation questionnaire (Cronbach's alpha coefficient = 0.89) was distributed among the students. A total of 129 questionnaires were completed and returned. Overall, 94.4% of the students believed that the program provided an excellent opportunity to reflect on professional behaviors during practical anatomy sessions. In addition, 92.8% of the students believed that they would use the ethical points mentioned in the program in the future. Content analysis of the open questions produced three main categories: "motivating learning", "application of theory in practice" and "changing the attitude toward responsibility". The results indicate that adequate preparation for cadaver dissection sessions and learning about professional behavior codes in the first exposure can help medical students to better understand the principles of professional behaviors.