(W1268) DEVELOPMENT OF MICROFABRICATED DEVICES FOR IN VITRO RECONSTRUCTION OF SENSORY NEURAL NETWORKS INDUCING HYPERSYNCHRONY BY STIMULATION OF SINGLE NEURONS
Abstract: While normal pain perception is essential for the survival of living organisms, chronic pain, a persistent form of pain, significantly reduces the quality of life of patients. Chronic pain is a persistent and difficult-to-treat condition. The rising treatment costs due to the growing number of patients have become a significant global concern. Pain is perceived when nociceptive stimuli trigger electrical activity in dorsal root ganglion (DRG) neurons, which transmit signals to the brain via the spinal cord. Alterations in the spinal cord's pain-processing circuitry can lead to chronic pain, such as nociplastic pain. Conventional animal model studies have limitations in investigating the complex mechanisms underlying changes in neural network function. In particular, tracking the progression of these changes over time is challenging. An experimental system capable of tracking changes in spinal cord networks in real time is essential for drug screening and the development of effective treatments tailored to the progression of chronic pain. In this study, we aimed to establish an experimental system to reconstruct the DRG-spinal cord network in vitro. Using the proposed co-culture method, we attempted functional changes in the spinal cord network, where changes in the input frequency from DRG neurons increased the synchronous activity of the spinal neurons. To establish the experimental methodology, microdevices were fabricated for co-culturing rat-derived DRG and spinal cord neurons on an electrode array. Electrical activity was induced by optogenetic stimulation of DRG neurons, and extracellular potentials of spinal cord neurons were recorded using high-density microelectrode arrays. Spinal cord neurons exhibited synchronous activity throughout the network before stimulation. During DRG neuron stimulation, the frequency of synchronous activity increased, a change that lasted for at least 20 minutes after stimulation. These results suggest that synaptic input from DRG neurons enhances the activity of spinal cord neurons. In conclusion, the sensory neural network reconstructed in this study offers a valuable platform for investigating the functional changes in the spinal cord network induced by sensory inputs.
Funding Source: This work was supported by JSPS, Grant Number 24K03248, and JST SPRING, Grant Number JPMJSP2108.
