A noninvasive IncuCyte method for analyzing C. elegans lifespan

[Speaker] Yoshio Nakano:1,2
[Co-author] Masataka Moriuchi:1,2, Go Kotaki:1,3, Mary Ann Suico:1, Hirofumi Kai:1,2, Tsuyoshi Shuto:1
1:Pharmaceutical Science, Kumamoto Univ., Japan, 2:HIGO Program, Kumamoto Univ., Japan, 3:POIE, Kumamoto Univ., Japan

C. elegans is a well-characterized and valuable tool as model organism. Despite its small length (1 mm), C. elegans has well-differentiated tissues such as nerve, muscle and intestine. Because C. elegans has a short lifespan (about 20 days) and their genes are highly conserved in human, it is an ideal living system to study the mechanisms of aging, life span and life extension. Specifically, to obtain data on survival of C. elegans, the number of living or dead C. elegans is scored depending on their response to prodding with a platinum wire observed under a microscope. However, there are three problems in this conventional method: 1) changes in light and temperature have influence on the lifespan of the C. elegans when they are taken out from the incubator; 2) because a lot of nematode is necessary for analysis, there is a time lag to complete a set of data; 3) the result is highly dependent on the skill of the researcher, resulting in issues of data reproducibility. To overcome these problems, we attempted to develop a novel method.
To measure the lifespan of C. elegans, we used the automated live-cell imaging and analysis system IncuCyte (Essen Bioscience). First, we determined the appropriate condition such as the number of C. elegans and the thickness of solid medium, etc. The Incucyte system records a series of images of C. elegans in the incubator at a specified time.
This method enables us to measure lifespan noninvasively, automatically and objectively. It also allows the examination of many samples at the same time (36 groups). Interestingly, compared with the conventional method, the IncuCyte method significantly prolonged the survival of C. elegans (25.6 days for IncuCyte vs. 21.6 days for conventional method; n=30/group). The result suggested that IncuCyte method eliminated the influencing factors such as light and changes in temperature that may be detrimental to the survival of C. elegans.
Thus, the use of IncuCyte might be better than the conventional method for the analysis of C. elegans lifespan.

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