Assessing testicular germ cell DNA damage in the comet assay; introduction of a proof-of-concept.
Environ Mol Mutagen
; 64(2): 88-104, 2023 02.
Article
en En
| MEDLINE
| ID: mdl-36629742
ABSTRACT
The in vivo comet assay is widely used to measure genotoxicity; however, the current OECD test guideline (TG 489) does not recommend using the assay to assess testicular germ cells, due to the presence of testicular somatic cells. An adapted approach to specifically assess testicular germ cells within the comet assay is certainly warranted, considering regulatory needs for germ cell-specific genotoxicity data in relation to the increasing global production of and exposure to potentially hazardous chemicals. Here, we provide a proof-of-concept to selectively analyze round spermatids and primary spermatocytes, distinguishing them from other cells of the testicle. Utilizing the comet assay recordings of DNA content (total fluorescence intensity) and DNA damage (% tail intensity) of individual comets, we developed a framework to distinguish testicular cell populations based on differences in DNA content/ploidy and appearance. Haploid round spermatid comets are identified through (1) visual inspection of DNA content distributions, (2) setting DNA content thresholds, and (3) modeling DNA content distributions using a normal mixture distribution function. We also describe an approach to distinguish primary spermatocytes during comet scoring, based on their high DNA content and large physical size. Our concept allows both somatic and germ cells to be analyzed in the same animal, adding a versatile, sensitive, rapid, and resource-efficient assay to the limited genotoxicity assessment toolbox for germ cells. An adaptation of TG 489 facilitates accumulation of valuable information regarding distribution of substances to germ cells and their potential for inducing germ cell gene mutations and structural chromosomal aberrations.
Palabras clave
Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
Espermatozoides
/
Testículo
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Environ Mol Mutagen
Asunto de la revista:
BIOLOGIA MOLECULAR
/
SAUDE AMBIENTAL
Año:
2023
Tipo del documento:
Article
País de afiliación:
Noruega