Biological responses of low-dose ionizing radiation from Oral and Maxillofacial spiral CT on human peripheral blood B lymphocytes.

BACKGROUND

X-ray examinations are widely used in oral and maxillofacial practice, but the biological effects of diagnostic low-dose ionizing radiation (LDIR) remain incompletely understood. Growing evidence indicates that even low doses can induce molecular and cellular alterations, highlighting the need to clarify LDIR-induced biological responses in dental imaging.

OBJECTIVE

To investigate the effects of LDIR generated by oral and maxillofacial spiral CT on cell viability, cell cycle distribution, and apoptosis in human peripheral blood B lymphocytes.

METHODS

Human peripheral blood B lymphocyte (IM-9) cells were exposed to low-dose ionizing radiation using a spiral CT scanner commonly employed in oral imaging. Cells were collected at 0.25 h, 1 h, 24 h and 48 h after radiation for the assessment of cell viability, cell cycle distribution and apoptosis. Statistical analyses were performed using GraphPad Prism 9.0, with data presented as mean ± SD; group comparisons were conducted using an unpaired Student's t-test, with P < 0.05 considered statistically significant.

RESULTS

Compared with the control group, LDIR exposure led to an increased proportion of cells in the G2/M phase at 1 h, a slight increase in early apoptotic cells at 0.25 h and 1 h, and enhanced cell viability at 48 h. These results indicate that LDIR induces transient cell cycle arrest and mild early apoptotic responses, followed by a promotion of cellular survival.

CONCLUSIONS

LDIR from oral and maxillofacial spiral CT induces a transient and adaptive biological response in human peripheral blood B lymphocytes, characterized by G2/M phase arrest and enhanced cell viability. This response may represent an adaptive defense mechanism adopted by cells to maintain viability and homeostasis.