Human MECP2 transgenic rats show increased anxiety, severe social deficits, and abnormal prefrontal neural oscillation stability.

Scientists created genetically modified rats with too much of a protein called MECP2, which causes a type of autism in humans. These rats showed autism-like behaviors including being very anxious and having trouble with social interactions, but they could move normally. The rats' brains also showed unusual activity patterns in areas important for social behavior. This gives researchers a better animal model to study autism and test new treatments.

This 2023 study developed a new rat model overexpressing human MECP2 protein to better understand MECP2 duplication syndrome, a genetic form of autism. The transgenic rats showed increased anxiety, severe social deficits including abnormal social approach and preference for social novelty, but maintained normal movement abilities. Brain recordings revealed abnormal neural oscillation patterns in the medial prefrontal cortex during social situations. Unlike existing mouse models that have movement problems interfering with behavioral testing, these rats provided cleaner autism-like behavioral phenotypes focused on social impairments.

The researchers suggest this model offers advantages for studying autism mechanisms and testing treatments.

This new rat model may accelerate autism research by providing a more suitable platform for studying social deficits and testing interventions. The preserved motor function allows clearer assessment of autism-specific behaviors compared to existing models with confounding movement disorders.

Sample size not reported. Only preliminary exploration of neural mechanisms. Single study establishing new model requires replication. Behavioral assessments limited to anxiety and social measures. Long-term developmental outcomes not evaluated.

Methylated CpG binding protein 2 (MeCP2) plays an important role in the development and normal function of the neural system. Abnormally high expression of MECP2 leads to a subtype of autism called MECP2 duplication syndrome and MECP2 is considered one of the key pathogenic genes for autism spectrum disorders. However, the effect of MECP2 overexpression on neural activity is still not fully understood. Thus, transgenic (TG) animals that abnormally overexpress MeCP2 are important disease models in research on neurological function and autism.

To create an animal model with a stronger and more stable autism phenotype, this study established a human MECP2 TG rat model and evaluated its movement ability, anxiety, and social behavior through behavioral tests. The results showed that MECP2 TG rats had an abnormally increased anxiety phenotype and social deficits in terms of abnormal social approach and social novelty preference, but no movement disorder. These autism-like behavioral phenotypes suggest that human MECP2 TG rats are suitable models for studying autism as they show more severe social deficit phenotypes and without interference from movement disorders affecting other phenotypes, which is an issue for mouse models with MECP2 duplication. In addition, this study performed preliminary exploration of the influence of the human MECP2 transgene on neural oscillation stability of the medial prefrontal cortex (mPFC), which is an important brain region for social interactions.

Oscillation stability in MECP2 TG rats showed abnormal responses to social conditions. Overall, the results of this study provide a new research tool for understanding the mechanism of social impairment and treatment of autism. The results also provide evidence for the influence of MECP2 duplication on mPFC neural activity.