Feature: Meet planarian, the newcomer to China's space station for life science experiment

JIUQUAN, April 24 (Xinhua) -- As the Shenzhou-20 manned spacecraft and the Long March-2F Y20 carrier rocket stand ready at the launch site on Thursday, a tiny but extraordinary passenger is being prepared to ride fire into space.

This unusual creature is the planarian, a flatworm that scientists say boasts unparalleled ability to regenerate.

Measuring no larger than a fingernail, the planarian, with a lineage stretching back over 520 million years, is one of Earth's oldest living creatures.

When cut in half, both segments of the worm can regrow complete heads and tails within just seven to 10 days. Even when sliced into numerous pieces, each fragment can regenerate into a fully functional individual.

The Shenzhou-20 crewed spaceflight mission marks China's first space-based investigation into the regeneration of planarians, the China Manned Space Agency spokesman Lin Xiqiang said at a press conference on Wednesday.

The new life science experiments to be conducted in China's space station during this mission involve zebra fish, planarians and Streptomyces, following the successful inclusion of zebrafish and fruit flies in previous space station experiments.

"This planarian project will enhance our understanding of the fundamental mechanisms of regeneration at the individual level and could provide insights into human health issues related to space-induced injuries," said Lin.

But why are researchers sending these tiny creatures into orbit? What revolutionary breakthroughs can their experiments bring to medical research?

According to Zhen Hui, a researcher at the School of Life Sciences and Medicine at Shandong University of Technology, which is responsible for the planarian study, the planarians selected for this mission are asexually reproduced Dugesia japonica.

"Planarians are one of the most commonly used model organisms in biological research due to their incredible regenerative abilities," explained Zhen.

"Even when severed in two, each half can regrow new muscles, skin, intestines, and even an entirely new brain -- a process that can be repeated indefinitely."

Studying these creatures could provide critical insights into human cell regeneration, aging resistance, and longevity, said Zhen.

Professor Zhao Bosheng, also from Shandong University of Technology, said that the way that the creature's stem cells proliferate and differentiate into various tissues and organs remains a mystery.

"Given the genetic similarities between planarians and mammals, the research could aid in understanding human diseases and tissue repair," said Zhao.

The upcoming experiment aims to investigate how the space environment, particularly microgravity and cosmic radiation, affects planarian regeneration.

Scientists hope to uncover the molecular mechanisms behind tissue repair under extraterrestrial conditions, which could advance space medicine and human cell regeneration studies.

"The space station presents a unique composite environment. Will these conditions alter the planarians' regeneration? If certain genes change in space, accelerating regeneration, we want to know why," said Zhao.

To conduct the study, researchers designed a specialized chip-equipped experiment box containing 48 planarian segments, stored in a temperature-controlled container aboard the Shenzhou-20 spacecraft.

Once in orbit, astronauts will transfer the box to the space station's life science cabinet, where automated systems will manage fluid changes, imaging, and data transmission.

A synchronized ground experiment will run in parallel for comparison.

"The first, third, and fifth days are critical for regeneration, so we divided the planarians into three modules, each with 16 segments," Zhao explained.

After the mission, astronauts will return the samples to Earth for genomic analysis, revealing differences between space and Earth-based regeneration.

With preparations complete, scientists eagerly await the results. "This experiment could provide key technical support for future space medicine and human tissue repair," Zhao said.

As China's space station continues pioneering research, these tiny creatures may hold answers to some of science's biggest questions. ■