Carranza-Aguilar César J, Hernández-Mendoza Araceli, Mejias-Aponte Carlos, Rice Kenner C, Morales Marisela, González-Espinosa Claudia, Cruz Silvia L
Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav, IPN), Sede Sur, Calzada de los Tenorios No. 235, Col. Granjas Coapa, Del. Tlalpan, C.P. 14330, Ciudad de México, Mexico.
Neuronal Networks Section, Integrative Neuroscience Research Branch, National Institute on Drug Abuse, 251 Bayview Boulevard Suite 200, Baltimore, MD, 21224, USA.
Cell Mol Neurobiol. 2022 Apr;42(3):677-694. doi: 10.1007/s10571-020-00957-5. Epub 2020 Sep 14.
Morphine promotes neuroinflammation after NOD-like receptor protein 3 (NLRP3) oligomerization in glial cells, but the capacity of other opioids to induce neuroinflammation and its relationship to the development of analgesic tolerance is unknown. We studied the effects of morphine and fentanyl on NLRP3 inflammasome activation in glial and neuronal cells in the dorsal raphe nucleus (DRN), a region involved in pain regulation. Male Wistar rats received i.p. injections of morphine (10 mg/kg) or fentanyl (0.1 mg/kg) 3 × daily for 7 days and were tested for nociception. Two hours after the last (19th) administration, we analyzed NLRP3 oligomerization, caspase-1 activation and gasdermin D-N (GSDMD-N) expression in microglia (CD11b positive cells), astrocytes (GFAP-positive cells) and neurons (NeuN-positive cells). Tolerance developed to both opioids, but only fentanyl produced hyperalgesia. Morphine and fentanyl activated NLRP3 inflammasome in astrocytes and serotonergic (TPH-2-positive) neurons, but fentanyl effects were more pronounced. Both opioids increased GFAP and CD11b immunoreactivity, caspase-1 and GSDMD activation, indicating pyroptotic cell death. The opioid receptor antagonist (-)-naloxone, but not the TLR4 receptor antagonist (+)-naloxone, prevented microglia activation and NLRP3 oligomerization. Only (+)-naloxone prevented astrocytes' activation. The anti-inflammatory agent minocycline and the NLRP3 inhibitor MCC950 delayed tolerance to morphine and fentanyl antinociception and prevented fentanyl-induced hyperalgesia. MCC950 also prevented opioid-induced NLRP3 oligomerization. In conclusion, morphine and fentanyl differentially induce cell-specific activation of NLRP3 inflammasome and pyroptosis in the DRN through TLR4 receptors in astrocytes and through opioid receptors in neurons, indicating that neuroinflammation is involved in opioid-induced analgesia and fentanyl-induced hyperalgesia after repeated administrations.
吗啡在胶质细胞中NOD样受体蛋白3（NLRP3）寡聚化后促进神经炎症，但其他阿片类药物诱导神经炎症的能力及其与镇痛耐受性发展的关系尚不清楚。我们研究了吗啡和芬太尼对中缝背核（DRN）中胶质细胞和神经元细胞中NLRP3炎性小体激活的影响，DRN是一个参与疼痛调节的区域。雄性Wistar大鼠每天腹腔注射吗啡（10mg/kg）或芬太尼（0.1mg/kg），共3次，持续7天，并进行痛觉测试。在最后一次（第19次）给药后2小时，我们分析了小胶质细胞（CD11b阳性细胞）、星形胶质细胞（GFAP阳性细胞）和神经元（NeuN阳性细胞）中NLRP3寡聚化、半胱天冬酶-1激活和gasdermin D-N（GSDMD-N）表达。对两种阿片类药物均产生了耐受性，但只有芬太尼产生了痛觉过敏。吗啡和芬太尼激活了星形胶质细胞和5-羟色胺能（TPH-2阳性）神经元中的NLRP3炎性小体，但芬太尼的作用更明显。两种阿片类药物均增加了GFAP和CD11b免疫反应性、半胱天冬酶-1和GSDMD激活，表明细胞发生焦亡性死亡。阿片受体拮抗剂（-）-纳洛酮而非TLR4受体拮抗剂（+）-纳洛酮可防止小胶质细胞激活和NLRP3寡聚化。只有（+）-纳洛酮可防止星形胶质细胞激活。抗炎药米诺环素和NLRP3抑制剂MCC950延迟了对吗啡和芬太尼镇痛作用的耐受性，并预防了芬太尼诱导的痛觉过敏。MCC950还可防止阿片类药物诱导的NLRP3寡聚化。总之，吗啡和芬太尼通过星形胶质细胞中的TLR4受体和神经元中的阿片受体差异性地诱导DRN中NLRP3炎性小体的细胞特异性激活和焦亡，表明神经炎症参与了重复给药后阿片类药物诱导的镇痛和芬太尼诱导的痛觉过敏。
