Combined Systemic and Cutaneous Ovalbumin–Aluminum Sensitization Triggers Thermal Hyperalgesia, Spinal Gliosis, and Nociceptive Nerve Fibers Sprouting in Mice

This study on ICR-CD1 mice demonstrates that combined systemic and cutaneous sensitization with ovalbumin-aluminum (OVA-AL) induces significant thermal hyperalgesia, spinal gliosis, and nociceptive nerve fiber sprouting. The experiment involved 6 mice treated with OVA-AL and 6 control mice treated with saline. OVA-treated mice showed increased sensitivity to heat, evidenced by shorter withdrawal latencies. Histological analysis revealed increased glial fibrillary acidic protein (GFAP) and IBA1 immunoreactivity in the spinal cord, indicating gliosis and microglial activation, along with enhanced calcitonin gene-related peptide (CGRP) and IB4 immunoreactivity, suggesting nociceptive fiber sprouting. Additionally, there was an elevated density of mast cells in the dorsal skin. These findings highlight the potential of OVA-AL sensitization as a model for studying pain mechanisms and neuro-immune interactions.