✍Effects of low-dose oxygen ions and protons on cardiac function and structure in male C57BL/6J mice

🌐Link to the paper: https://www.sciencedirect.com/.../pii/S2214552418300798...

The paper assesses the effects of charged-particle irradiation on cardiac function and structure and immune cell infiltration in a mouse model. The study found that low-dose, high-energy charged-particle irradiation caused mild changes in cardiac function and tissue remodeling in the mouse.

🟢According to the full text information provided, the contributions of this paper are as follows:

🔹The paper provides insights into the potential risk of degenerative cardiovascular disease during or after exposure to charged-particle irradiation during deep-space travel.

🔹The study characterizes the cardiovascular effects of whole-body exposure to high-energy charged particles in rodent models, which can help in understanding the biological effects of charged particles from human subjects.

🟣The practical implications of this paper are as follows:

🔸The findings of this study can help in developing countermeasures to mitigate the potential risks of cardiovascular disease during deep-space travel.

🔸The study can also help in designing radiation protection guidelines for astronauts and space travelers.

🔸The research can contribute to the development of new therapeutic strategies for cardiovascular diseases on Earth, as the study provides insights into the mechanisms of radiation-induced cardiovascular damage.

🔵The methods used in this paper are as follows:

♦️Male C57BL/6 J mice were exposed to oxygen ions (16O), protons, or γ-rays at different doses.

♦️Cardiac function and blood velocity were measured with ultrasonography at 3, 5, 7, and 9 months after irradiation.

♦️Cardiac tissue was collected at 2 weeks, 3 months, and 9 months after irradiation to assess apoptosis, tissue remodeling, and markers of immune cells.

♦️Pulsed-wave Doppler was used to determine mitral valve E and A velocities in a four-chamber view of the heart.

♦️Pulsed-wave Doppler was also used to determine abdominal aortic blood flow as an indicator of both cardiac and vascular function.

♦️Immunoblots were used to measure the protein amounts of cluster of differentiation (CD)2, CD68, and CD45 as markers of immune cell infiltration.

♦️Toluidine Blue staining was used to quantify mast cells, and eosin was used as a counterstain.

♦️Apoptotic nuclei were identified with the CardioTACS™ Kit, which is based on DNA end-labeling with terminal deoxynucleotidyl transferase.

Overall, the study used a combination of in vivo and ex vivo methods to assess the effects of charged-particle irradiation on cardiac function and structure in a mouse model.

The data used in this paper is raw data that is available in the NASA Ames Life Sciences Data Archive at https://lsda.jsc.nasa.gov/. The authors performed statistical analyses on this data to assess the effects of charged-particle irradiation on cardiac function and structure in a mouse model. They used two sets of analyses: one for 20 longitudinal outcomes and another for 16 static outcomes. Within each of these cohort-specific analyses, they compared each radiation dose to its sham control within each time point. They performed 770 hypothesis tests for the longitudinal outcomes and 407 hypothesis tests for the static outcomes.

The results of the paper suggest that low-dose, high-energy charged-particle irradiation caused mild changes in cardiac function and tissue remodeling in the mouse model. Specifically, ejection fraction and fractional shortening decreased at 3 and 7 months after exposure to oxygen ions (16O), but not after exposure to γ-rays, protons, or protons followed by 16O. The authors also observed changes in the levels of a truncated peptide of type III collagen and mast cell tryptase in the left ventricle, which suggest that there may have been some remodeling of the existing extracellular matrix in the heart. However, they did not observe an increase in total collagen deposition in the heart or aorta, indicating that radiation fibrosis did not occur. The authors also found evidence of immune cell infiltration in the heart after exposure to protons or 16O alone, as measured by the protein amounts of cluster of differentiation (CD)2, CD68, and CD45. Overall, the study provides insights into the potential effects of space radiation on the cardiovascular system, which is important for the safety of astronauts traveling beyond low-Earth orbit.

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