Interleukin-6 Microinjection Protocol Established in TSC Zebrafish Larvae to Model Neuropsychiatric Behaviors

Patients with Tuberous Sclerosis Complex (TSC1/TSC2 mutations) frequently exhibit varying degrees of Autism Spectrum Disorder (ASD), a complex neurodevelopmental disorder. Maternal immune activation during pregnancy is a known risk factor for ASD, suggesting a critical role for inflammation. Interleukin-6 (IL-6), a pleiotropic pro-inflammatory cytokine, is implicated in neuroinflammation and can cross the blood-brain barrier, linking it to inflammation-associated neuropsychiatric conditions like ASD and intellectual disability (ID). Understanding how systemic inflammation impacts early neurodevelopment in genetically susceptible individuals remains a significant research gap.

Researchers developed a detailed protocol for inducing systemic inflammatory signaling in zebrafish larvae by delivering Interleukin-6 directly into the bloodstream. The method involves microinjection of IL-6 into the duct of Cuvier, a major blood vessel, in TSC zebrafish larvae. This approach aims to establish controlled and reproducible inflammatory responses to investigate inflammation-driven changes during early development. The protocol outlines essential steps for IL-6 preparation, precise microinjection techniques, and subsequent experimental applications in zebrafish models of disease and neuroinflammation, specifically designed to probe gene-environment interactions.

The developed protocol successfully establishes a controlled and reproducible method for inducing systemic inflammatory signaling in zebrafish larvae. This precise delivery of Interleukin-6 into the bloodstream via the duct of Cuvier enables researchers to reliably trigger inflammatory responses in early developmental stages. The protocol provides a robust platform for examining how genetic susceptibility, such as that found in Tuberous Sclerosis Complex (TSC) models, interacts with inflammatory exposures to shape developmental outcomes. It specifically facilitates studies on inflammation-driven changes in neurodevelopment and the emergence of neuropsychiatric disorder-like behaviors, offering a valuable tool for understanding complex gene-environment interactions relevant to conditions like Autism Spectrum Disorder (ASD). The method's reproducibility ensures consistent inflammatory induction, critical for comparative studies and mechanistic investigations.

This approach provides a versatile platform for examining how genetic susceptibility and inflammatory exposures intersect to shape developmental outcomes.