EFFECTS OF EXPOSURE TO RADIOACTIVE 56MnO2 POWDER ON HYALURONAN SYNTHASE 2 IN THE LUNGS OF RATS.

Area of Science:

• Radiobiology
• Molecular Biology
• Environmental Health

Background:

• Manganese-56 (56Mn) is a radioisotope produced in soil by atomic bomb neutrons.
• Previous studies showed 56Mn internal exposure causes lung and small intestine pathology in Wistar rats.

Purpose of the Study:

• To investigate the effect of internal 56Mn exposure on hyaluronan synthase 2 (Has2) gene expression in rat lungs.
• To compare the biological impact of internal 56Mn radiation with external gamma (γ)-rays.

Main Methods:

• Ten-week-old male Wistar rats were exposed to neutron-activated 56MnO2 powder, non-radioactive MnO2 powder, or external 60Co γ-rays (2 Gy).
• Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to analyze Has2 gene expression in lung tissue on days 3, 14, and 60 post-exposure.
• Absorbed doses in the lung from 56Mn exposure ranged from 55-110 mGy.

Main Results:

• 56Mn exposure significantly reduced Has2 gene expression in the rat lung.
• External γ-ray exposure did not alter Has2 gene expression.
• Internal 56Mn exposure demonstrated a significant biological impact at low absorbed doses.

Conclusions:

• Internal exposure to low-dose Manganese-56 radioisotope significantly suppresses Has2 gene expression in the lung.
• This suggests internal 56Mn radiation has a distinct and significant biological effect on lung tissue compared to external radiation.