Chemotherapy-induced peripheral neuropathy and the accompanying affective disorders are serious side effects, and their resolution is not guaranteed. Oxidative stress and elevated levels of Nod-like receptor protein 3 (NLRP3) have been detected in the peripheral and central nervous systems of animals with neuropathic pain provoked by several antineoplastic drugs, such as paclitaxel (PTX). Several studies have further indicated that NLRP3 inflammasome inhibition could be an approach for treating chronic pain, but its impact on the anxiodepressive-like behaviors and memory deficits related to PTX-provoked neuropathy has not yet been investigated. MCC950 is a potent and specific inhibitor of the NLRP3 pathway that acts through inhibiting NLRP3 activation and inflammasome formation. We hypothesized that the administration of MCC950 could alleviate the affective and cognitive disorders accompanying PTX-provoked neuropathy. Using male C57BL/6 mice, we assessed the effects of MCC950 on the mechanical and thermal allodynia, anxiodepressive-like behavior, and memory deficits incited by this taxane. The results indicated that the intraperitoneal administration of 10 mg/kg of MCC950 twice daily for three consecutive days fully reversed the PTX-induced mechanical and thermal allodynia. This treatment also completely attenuated the anxiolytic (p < 0.004) and depressive-like behaviors (p < 0.022) and memory deficits (novel object recognition test; p < 0.0018) incited by PTX. These actions were mainly achieved through blocking NLRP3 inflammasome activation in the sciatic nerve, amygdala, and hippocampus, and oxidative stress in the amygdala and hippocampus. MCC950 also normalized the p-ERK 1/2 overexpression in the sciatic nerve and apoptotic responses in the sciatic nerve and the amygdala. This study suggests that MCC950 might be a promising treatment for PTX-induced mental illnesses and neuropathy.

Cisplatin (CIS)-induced peripheral neuropathy and associated comorbidities have a detrimental effect on the lives of cancer patients. Currently, there are no effective therapies to alleviate these symptoms. Duloxetine (DULO) is a recommended treatment, but it is linked with important side effects, thus making it essential to explore novel approaches. We examined the impact of a prophylactic treatment with a low dose of DULO combined with hydrogen-rich water (HRW) on CIS-injected C57BL/6 male and female mice as a possible therapy for allodynia, muscle and body weight deficits, and emotive syndromes accompanying this type of chemotherapy. The prophylactic treatment with DULO and HRW prevented mechanical allodynia caused by CIS in both sexes and had greater effects than either treatment given individually. The combined treatment also prevented cold allodynia in male mice but only reduced it in females. Moreover, the coadministration of DULO with HRW avoided muscular deficits in both sexes. Furthermore, the body weight reduction induced by CIS in both sexes was not entirely mitigated by the combined therapy. However, all treatments avoided the anxiety- and depressive-like behaviors elicited by CIS. The antiallodynic actions and prevention of muscular deficits produced by the combined treatment might be explained by the inhibition of oxidative stress, inflammatory responses, and plasticity alterations provoked by CIS in the dorsal root ganglia of these subjects. This study proposes, for the first time, the cotreatment of DULO with HRW as an effective therapy for CIS-induced peripheral neuropathy and reveals the influence of sex on these actions.

Fibromyalgia is a chronic nociplastic pain condition frequently accompanied by affective disturbances, particularly depression, for which effective treatments remain limited. Increasing evidence implicates central oxidative stress, maladaptive synaptic plasticity, and neuroinflammatory alterations in its pathophysiology. This study investigated the therapeutic effects of molecular hydrogen (H₂) in a reserpine-induced murine model of fibromyalgia, with emphasis on sex-dependent and region-specific mechanisms. Male and female C57BL/6 mice received repeated reserpine injections to induce fibromyalgia-like symptoms. Mechanical allodynia, thermal hyperalgesia, cold allodynia, and depressive-like behaviors were assessed, followed by molecular analyses in the spinal cord and amygdala. Reserpine induced persistent nociceptive hypersensitivity and depressive-like behaviors in both sexes, with earlier cold allodynia in females. Hydrogen-rich water (HRW) progressively reversed mechanical and thermal hypersensitivity and rapidly abolished cold allodynia, showing greater efficacy in females. HRW also normalized depressive-like behaviors in both sexes. At the molecular level, HRW reduced spinal oxidative stress and ERK-dependent plasticity without altering spinal NLRP3 expression, whereas it fully reversed NLRP3 upregulation and HO-1 downregulation in the amygdala. HRW additionally engaged sex-dependent antioxidant pathways in the spinal cord. These findings indicate that H₂ alleviates sensory and affective alterations through region- and sex-dependent central mechanisms, supporting HRW as a promising therapeutic strategy for nociplastic pain and its affective comorbidities.

Neuropathic pain (NP) is a complex and disabling condition that often requires long-term treatment with high doses of pharmacological agents, frequently resulting in significant adverse side effects. Therefore, safer and more effective therapeutic approaches are urgently needed. Molecular hydrogen, recognized for its antioxidant and anti-inflammatory actions, may act as a valuable adjunct to conventional analgesics. This study examined whether hydrogen-rich water (HRW) could potentiate the analgesic effects of JWH-133, a selective cannabinoid receptor type 2 agonist, and pregabalin, a gabapentinoid, in male C57BL/6 mice with NP induced by chronic constriction of the sciatic nerve. Mechanical allodynia, thermal hyperalgesia, and cold allodynia were assessed following separate or combined administration of HRW with JWH-133 or pregabalin. Western blot analyses of dorsal root ganglia measured markers of oxidative stress (4-HNE), inflammation (NLRP3), synaptic plasticity (p-ERK), and nociceptive signaling (p-AKT). Each treatment reduced pain-like behaviors in a dose-dependent manner, while co-administration of HRW with JWH-133 or pregabalin produced greater analgesic effects. Combined treatments also diminished oxidative stress, inflammation, maladaptive neural changes and nociceptive pathways activated by peripheral nerve injury. These findings suggest HRW as a promising adjuvant to cannabinoid and gabapentinoid therapies, potentially improving efficacy and reducing high-dose drug-related adverse effects.

Dor é uma experiência pessoal e subjetiva que pode apenas ser sentida pelo sofredor. A dor aguda tem a finalidade de avisar o indivíduo que algo está errado. Contudo, a dor crônica (DC) é um problema global de saúde, que afeta a qualidade de vida e torna o indivíduo parcial ou totalmente incapacitado. A pesquisa básica utiliza diversos modelos animais para o estudo da dor aguda ou crônica, bem como para o estudo das principais comorbidades oriundas de sua cronificação como a ansiedade e a depressão. Esta revisão aborda os modelos animais mais comumente utilizados neste contexto.