Analysis of Single- and Double-Stranded DNA Damage in Osteoblastic Cells after Hyperbaric Oxygen Exposure

Area of Science:

• Biomedical Science
• Cell Biology
• Hyperbaric Medicine

Background:

• Hyperbaric oxygen (HBO) exposure can induce oxidative stress and DNA damage in various cell types.
• The effects of hyperbaric conditions on human osteoblastic cells (HOBs and SAOS-2) were previously uncharacterized.

Purpose of the Study:

• To investigate the impact of hyperbaric oxygen exposure on DNA damage and cellular responses in human osteoblastic cell lines.
• To assess DNA damage, apoptosis, and gene expression related to antioxidative functions under hyperbaric conditions.

Main Methods:

• Human osteoblasts (HOBs) and SAOS-2 cells were exposed to hyperbaric oxygen (4 ATA, 100% O2, 4h) or sham conditions (1 ATA, air, 4h).
• DNA damage was evaluated using the alkaline comet assay and detection of double-strand break (DSB) foci (γH2AX+53BP1).
• Apoptosis and gene expression of TGFß-1, HO-1, and NQO1 were analyzed via qRT-PCR.

Main Results:

• Significantly elevated DNA damage, mainly single-strand breaks, was observed in both cell lines post-HBO exposure.
• DSB foci remained similar to sham-exposed cells, with a slight increase in apoptosis.
• Upregulation of HO-1 indicated an antioxidative response, while TGF-ß1 expression was reduced in HOB cells.

Conclusions:

• Osteoblastic cells are susceptible to DNA-damaging effects of hyperbaric hyperoxia.
• HBO-induced DNA damage in these cells primarily involves rapidly repaired single-strand breaks.
• The cells exhibit an antioxidative response to hyperbaric oxygen exposure.