Radiation-induced cell death is classified into interphase death and reproductive death. Reproductive cell death (RCD) occurs after one or more cell divisions following an insult such as radiation or treatment with carcinogens or mutagens. The radio-adaptive response for RCD is usually investigated using in vitro or in vivo clonogenic assay. However, there is few report on the vulval tissue in Caenorhabditis elegans (C. elegans), which is a well established model in vivo for radiation-induced reproductive cell death.

A study team led by Prof. BIAN Po in Institute of Technical Biology & Agriculture Engineering, Hefei Institutes of Physical Science (CAHIPS), made great progress in investigating the occurrence of radio-adaptive response for RCD in the vulval tissue model of C. elegans. Their study entitled Radio-adaptive Response for Reproductive Cell Death Demonstrated inin vivoTissue Model ofCaenorhabditis elegans was published in Radiation Research.

Researchers found that the radio-adaptive response for RCD in vulval tissue model could be well induced by dose combinations of 5+75 Gy and 5+100 Gy at the time point of 14-16 h of worm development. And the analysis of time course indicated that radio-resistance in vulval cells developed within 1.75 h after adaptive irradiation and persisted only for a short time (2-4 h).

Furthermore, the study also reported that DNA damage checkpoint and non-homologous end joining (NHEJ) were involved in the radio-adaptive response, exhibiting similar induction of protruding vulva in worms deficient in these two pathways with their controls. Interestingly, the DNA damage checkpoint is not active in the somatic vulval cells, which therefore suggested that the DNA damage checkpoint might mediate radio-adaptive response in a cell non-autonomous manner.

These findings provide basis for further understanding of radio-adaptive responses and their underlying mechanisms. And this work was supported by the grants from National Natural Science Foundation of China.

Schematics of radiation-induced phenotype of protruding vulva in C. elegans. (Image by TANG Huangqi) 

The formation of radio-adaptive response by various dose combinations at the time point of A14-C16 h of worm development. A) 50 Gy of challenge irradiation; B) 75 Gy of challenge irradiation; C) 100 Gy of challenge irradiation; D) 150 Gy of challenge irradiation. (Image by TANG Huangqi)