AIM: To investigate whether the microgravity environment is related to retinal damage.

METHODS: Hanging-tail mice tests were used to simulate weightlessness. Light microscopy, and transmission electron microscopic examinations of the retinal tissue structure were used to observe morphological changes. Immunohistochemistry and Western blot analyses were performed to detect the molecular changes associated with the observations.

RESULT: Light microscopy and transmission electron microscopy demonstrated that more dead cells were detected in the ganglion layer and inner nuclear layer cells. TNF-α and caspase-3 protein expression in the retinas of simulated microgravity groups were up-regulated compared with the ground-based control group.

CONCLUSION: The results demonstrated that simulated microgravity produced severe pathological damage in the retinas of mice.