Motor and molecular analysis to detect the early symptoms in a mouse amyotrophic lateral sclerosis model

The amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disorder primarily involving motoneurons in the cerebral cortex, brainstem, and spinal cord. SOD1-G93A mice, which express multiple copies of the mutant form of the human Cu/Zn SOD, are one of the most widely used animal models for ALS pathology. However, the onset of the disease can vary between animals of 1-2 weeks while the progression is quite fast. In order to evaluate the efficacy of any treatment, it is very important to treat all animals at the early onset of the disease, instead of at a fixed age-point. To this aim, we performed behavioral analysis and measured hSOD1 mRNA expression to identify the appearance of the first motor deficits. Rotarod and PaGE tests revealed to be the most sensitive approaches to detect the beginning of the symptomatic phase of the disease, while neurological score and weight monitoring showed significant differences only at later stages in ALS pathology. Furthermore, we found a better correlation between hSOD1 mRNA expression with disease onset than with a transgene copy number. Therefore, the association of behavioral tests and molecular analysis represents a sensible and accurate tool to early detect the murine symptoms.