Targeted Central Nervous System Irradiation of Caenorhabditis elegans Induces a Limited Effect on Motility

Abstract

To clarify the tissue responsible for a biological function, that function can be experimentally perturbed by an external stimulus, such as radiation. Radiation can be precisely and finely administered and any subsequent change in function examined. To investigate the involvement of the central nervous system (CNS) in Caenorhabditis elegans’ locomotion, we irradiated a limited 20-µm-diameter area of the CNS with a single dose and evaluated the resulting effects on motility. However, whether irradiated area (beam size)-dependent or dose-dependent effects on motility occur via targeted irradiation remain unknown. In the present study, we examined the irradiated area- and dose-dependent effects of CNS-targeted irradiation on the motility of C. elegans using a collimating microbeam system and confirmed the involvement of the CNS and body-wall muscle cells around the CNS in motility. After CNS-targeted microbeam irradiation, C. elegans’ motility was assayed. The results demonstrated a dose-dependent effect of CNS-targeted irradiation on motility reflecting direct effects on the irradiated CNS. In addition, when irradiated with 1000-Gy irradiation, irradiated area (beam size)-dependent effects were observed. This method has two technical advantages: Performing a series of on-chip imaging analyses before and after irradiation and targeted irradiation using a distinct ion-beam size.

Review of Biological Effects of Acute and Chronic Radiation Exposure on Caenorhabditis elegans

“…Another study by Suzuki et al presents evidence of the CNS's activity in reducing the mortality in adult hermaphrodite C. elegans due to acute irradiation. Research shows that decreased mortality after irradiation of the CNS depends on the dose, and the body muscle around the CNS is also partly involved in reducing the mortality [73]. A device that makes the researcher able to partially irradiate C. elegans has recently been developed by Funayama et al [74].…”

“…Maremonti et al, 2019 [89] Targeted micro bream (12C ion particles) 0, 500, 100, and 1500 Gy The decrease in mortality depends on the dose due to central nervous system (CNS) targeted irradiation and may partly be due to body-wall muscle cells around the CNS. Suzuki et al, 2020 [73] Targeted micro bream (12C ion particles) 500 Gy Targeted heavy ion microbeam smaller than 10 µm. The preparation and irradiation method for the device is provided.…”

High-Dose Irradiation Inhibits Motility and Induces Autophagy in Caenorhabditis elegans

“…Previous studies reported that the locomotion of adult worms was reduced by 1420 Gy of γ-ray irradiation [19] or 1 kGy of carbon-ion beam irradiation [17]. However, little is known about the effects of higher doses on locomotion.…”

“…Body bends (head bends for 20 s) were significantly reduced when the whole body was irradiated with 0.5 kGy of carbon ions [19]. Irradiation with 1 kGy of carbon beams reduced the locomotion [15,18,19]. In this manner, non-dividing and dividing cells are different in their radiosensitivity.…”

“…High-dose irradiation causes a temporary decrease in locomotion [18]. Body bends (head bends for 20 s) were significantly reduced when the whole body was irradiated with 0.5 kGy of carbon ions [19]. Irradiation with 1 kGy of carbon beams reduced the locomotion [15,18,19].…”