Study explains negative effects of microgravity on astronauts

Melbourne, Sept 29 (ANI): Scientists from University of New South Wales in Sydney claim to have found the reason why long-term exposure to microgravity causes loss of bone density and muscle wasting in astronauts.

They said stem cells exposed to microgravity express different proteins than those grown in normal gravity.

During the study, lead researcher Dr Brendan Burns and colleagues Elizabeth Blaber and Helder Marcal used a NASA rotating-wall vessel to simulate microgravity, which is experienced by astronauts in low Earth orbit, to analyse its effect on human embryonic stem cells.

They separated the proteins expressed by the cells and compared these to proteins from cells grown under normal gravity conditions.

The analysis shows that 75pct of the proteins from the cells exposed to microgravity were not found in those grown under normal gravity.

The cells exposed to microgravity produced more proteins that negatively regulate bone density.

In the human body, these changes in bone tissue could result in decreases in bone density, leading to osteoporosis.

"A lot of work has been done on microgravity at a systemic level, such as the effects on the immune system. No one has really looked at the effect of microgravity at a cellular level and we think that is a huge gap," ABC Online quoted Burns as saying.

"What we've found is a range of different proteins that are potentially important for astronaut health were more or less predominant in terms of different gravity," he added.

The study will be presented this week at the 9th Australian Space Sciences Conference. (ANI)