Low-dose X-Ray induced genetic damage in human peripheral blood lymphocytes

Area of Science:

• Cytogenetics
• Radiation Biology
• Human Genetics

Background:

• X-rays (XR) are widely used but their low-dose health impacts are unclear.
• XR exposure can cause DNA damage and chromosomal alterations, potentially leading to disease.
• Previous studies lack detailed characterization of XR-induced cytogenetic damage.

Purpose of the Study:

• To characterize the type and frequency of chromosomal alterations and genetic damage in human lymphocytes exposed *in vitro* to a low X-ray dose (94.33 mGy).
• To identify specific chromosomes and types of alterations most affected by low-dose XR exposure.
• To assess the relevance of biosafety and cytogenetic monitoring for XR exposure.

Main Methods:

• Human lymphocytes from 12 healthy donors were exposed *in vitro* to 94.33 mGy X-rays.
• Genetic damage was assessed using GTG-banding cytogenetics and the cytokinesis-block micronucleus (MN) assay.
• Clonal and non-clonal alterations were analyzed in irradiated and control samples.

Main Results:

• Irradiated samples showed significantly higher frequencies of chromosomal alterations and fragile sites (p ≤ 0.0093).
• Monosomies were the most frequent numerical alteration, with chromosomes 8 and 21 most affected (50% of samples).
• Structural alterations involved chromosomes 11, 16, and 17; MN frequency increased significantly (p = 0.0214); women had higher MN frequencies.

Conclusions:

• Low-dose X-ray exposure induces detectable chromosomal damage in human lymphocytes.
• Specific chromosomes (8, 21, 11, 16, 17) and alteration types (monosomies, deletions) are particularly sensitive.
• Cytogenetic monitoring and biosafety practices are crucial even for doses traditionally considered safe.