In vivo imaging reveals rapid morphological reactions of astrocytes towards focal lesions in an ALS mouse model.

Pathophysiology of the motoneuron disease amyotrophic lateral sclerosis (ALS) is non-cell-autonomous. In mouse models of familiar ALS, neurotoxicity is derived not only from mutant motor neurons but also from mutant neighbouring glial cells. In vivo imaging by two-photon laser-scanning microscopy was used to study rapid morphological reactions of astroglial cells towards laser-induced axonal transection in ALS-linked transgenic SOD1(G93A) mice. In the affected lateral spinal cord, mutated astroglial cells extended branches towards injured axons within a time frame of minutes to hours post lesion while in control animals astrocytes lack any rapid morphological alteration within the studied time frame. This suggests that astrocytes partially contribute to the rapid response of non-neuronal cells to acute axonal lesions in ALS mice.