Unit:
Κατεύθυνση Μοριακή και Εφαρμοσμένη ΦυσιολογίαLibrary of the School of Health Sciences
Author:
Papadopetraki Argyro
Supervisors info:
Φιλίππου Αναστάσιος, Επίκουρος Καθηγητής, Ιατρική, ΕΚΠΑ
Κουτσιλιέρης Μιχαήλ, Καθηγητής, Ιατρική, ΕΚΠΑ
Μαριδάκη Μαρία, Αναπληρώτρια Καθηγήτρια, ΣΕΦΑΑ, ΕΚΠΑ
Original Title:
H επίδραση του εκκρινώματος καρδιομυοβλαστών μετά από μηχανική φόρτιση σε καρδιομυοβλάστες που υπόκεινται σε υποξία/επανοξυγόνωση τραυματισμό
Translated title:
The effect of Cardiomyoblast Secretome after mechanical loading, on cardiomyoblasts subjected to Hypoxia Reoxygenation injury
Summary:
INTRODUCTION: Reperfusion after myocardial infarction (MI) can worsen cardiac tissue damage and in vitro models of hypoxia/reoxygenation (H/R) have been developed to simulate the in vivo tissue damage because of ischemia/reperfusion. Cardiac stem cells have been used for regeneration after MI due to their multipotency and paracrine actions in improving myocardial cell survival and function. Interestingly, mechanical loading of cardiomyoblasts may modulate their secretome.
PURPOSE: The aim of the study is to investigate the paracrine effects of cardiomyoblasts in H/R injury, by treating cardiomyoblasts that have been undergone H/R injury with the conditioned media (secretome) of mechanically loaded or unloaded cells, in vitro.
METHODS: H9C2 cardiomyoblasts were cultured on elastic membranes and underwent 2 different protocols of cyclic stretching and subsequently their conditioned media (secretome) was collected (stretch media, SM). Conditioned media of unstretched H9C2 was also collected (non-stretch media, NSM). H9C2 were subjected to hypoxia/reoxygenation injury while during reoxygenation, they were treated either with SM or NSM. Particularly, two conditions of hypoxia/reoxygenation were used: in the experimental condition A the cardiomyoblasts were subjected to 6 and 8 hours of hypoxia and reoxygenation respectively, while in the experimental condition B at 6 and 4 hours respectively. Cell apoptosis was assessed by flow cytometry (Annexin V/PI staining) and by the chemical process for monitoring cellular metabolic activity, MTT. Statistical analysis included non-parametric T-test and One-way ANOVA.
RESULTS: After the hypoxia period, the cell viability rate was 98%, without being significant different from the normoxia group (p>0.05), while after reoxygenation (8h), the viability rate decreased significantly to 50.6% (p <0.01). Following the treatment with the SM or the NSM, no statistical significant changes were observed in the experimental condition A. In contrast, in the second condition (B) the viability increased, both after the treatment with the SM (92%) and the NSM (80%), having no statistical significant differences from the normoxia group (p>0.05). Additionally, in the condition B, only the cells which have been treated with the SM displayed a significantly higher viability (p<0.05) compared with the cardiomyoblasts that have undergone H/R injury without taking any treatment and had a 74% viability rate.
CONCLUSION: Our findings suggest that cardiomyocytes are susceptible to H/R injury, displaying high rates of cellular death while their secretome is able to inhibit their apoptosis. Moreover, the mechanical loading of cardiomyoblasts modifies their secretome by making it more effective for the survival of these cells.
Main subject category:
Health Sciences
Keywords:
Cardiomyoblasts, Cardiac stem cells, Hypoxia, Reoxygenation, Secretome, Mechanical loading, Mechanical stretch
