NLRP3 and interstitial cystitis: This study demonstrated that extracellular vesicles derived from miR‐9‐enriched mesenchymal stem cells can freely cross the blood‐brain barrier into the spinal cord tissue, and then target TLR4 receptors on the activated spinal cord glial cell membrane of interstitial cystitis/bladder pain syndrome (IC/BPS) model to inhibit the activation of NLRP3 inflammatorome and release of inflammatory factors, which can reduce neuron stimulation and restore neuron firing threshold, so as to desensitize neurons and achieve the purpose of treating bladder pain in IC/BPS patients.