2-Bromopalmitate decreases spinal inflammation and attenuates oxaliplatin-induced neuropathic pain via reducing Drp1-mediated mitochondrial dysfunction.

Oxaliplatin (OXA) is a third-generation platinum compound with clinical activity in multiple solid tumors. Due to the repetition of chemotherapy cycle, OXA-induced chronic neuropathy presenting as paresthesia and pain. This study explored the neuropathy of chemotherapy pain and investigated the analgesic effect of 2-bromopalmitate (2-BP) on the pain behavior of OXA-induced rats. The chemotherapy pain rat model was established by the five consecutive administration of OXA (intraperitoneal, 4 mg/kg). After the establishment of OXA-induced rats, the pain behavior test, inflammatory signal analysis and mitochondrial function measurement were conducted. OXA-induced rats exhibited mechanical allodynia and spinal inflammatory infiltration. Our fluorescence and western blot analysis revealed spinal astrocytes were activated in OXA rats with up-regulation of astrocytic markers. In addition, NOD-, LRR- and pyrin domain-containing 3 (NLRP3) inflammasome mediated inflammatory signal cascade was also activated. Inflammation was triggered by dysfunctional mitochondria which represented by increase in cyclooxygenase-2 (COX-2) level and manganese superoxide dismutase (Mn-SOD) activity. Intrathecally injection of 2-BP significantly attenuated dynamin-related protein 1 (Drp1) mediated mitochondrial fission, recovered mitochondrial function, suppressed NLRP3 inflammasome cascade, and consequently decreased mechanical pain sensitivity. For cell research, 2-BP treatment significantly reversed tumor necrosis factor-α (TNF-α) induced mitochondria membrane potential deficiency and high reactive oxygen species (ROS) level. These findings indicate 2-BP decreases spinal inflammation and relieves OXA-induced neuropathic pain via reducing Drp1-mediated mitochondrial dysfunction.

Resveratrol ameliorates oxaliplatin-induced neuropathic pain via anti-inflammatory effects in rats.

Oxaliplatin (OXA) is a common chemotherapy drug and exhibits clinical activity in several cancer types. Its anticancer clinical effect is frequently accompanied by neurotoxicity. The symptoms include paresthesia and pain, which adversely affect the quality of life of patients. In the present study, five consecutive intraperitoneal injections of 4 mg/kg OXA were used to mimic chemotherapy in rats. OXA administration induced mechanical allodynia, activated spinal astrocytes and triggered the inflammatory response. To explore potential therapeutic options for OXA-induced neuropathic pain, resveratrol (Res) was intrathecally injected into the spinal cord of OXA-treated rats. Paw withdrawal threshold values of OXA-treated rats were increased, indicating an antinociception effect of Res on OXA-induced pain. Additionally, Res treatment reduced the levels of glial fibrillary acidic protein, TNF-α, IL-1ß and NF-κB, which were upregulated in OXA-treated rats (compared with control). Furthermore, Auto Dock data showed that Res binds to cyclooxygenase-2 (COX-2) through six hydrogen bonds. Western blot analysis and reactive oxygen species (ROS) assays indicated that Res treatment decreased COX-2 expression and suppressed ROS production. In summary, intrathecal injection of Res reduced the spinal COX-2-mediated ROS generation and inflammatory reaction, suppressed astrocytic activation, and alleviated OXA-induced neuropathic pain.