Abstract Purpose: To investigate the possible role of IL-4 signaling pathway in vincristine-induced peripheral neuropathy. Methods: The mouse model of vincristine-induced peripheral neuropathy and interleukin (IL)-4 knockout mice were utilized to investigate the possible role of IL-4 signaling pathway in vincristine-induced peripheral neuropathy. Vincristine induced increased sensitivity to mechanical stimulation was measured by von Frey hair test 7 and 14 days after intraperitoneal administration of 0.1 mg/kg vincristine in mice. Relative expression levels of cytokines were detected by quantitative real-time PCR. STAT6 expression following vincristine treatment was assessed with western blotting. Results: We discovered that IL-4/STAT6 signaling was down-regulated in vincristine-treated mice. Deletion of IL-4 in mice increased the sensitivity to mechanical allodynia. IL-4 knockout mice also produced more pro-inflammatory cytokines, including IL-1β and TNF-α. Notably, co-administration of exogenous recombination IL-4 significantly prevented vincristine-induced mechanical allodynia. Conclusion: Anti-inflammatory cytokine IL-4 protects rodent model from vincristine-induced peripheral neuropathy via the stimulation of IL-4/STAT6 signaling and inhibition of the pro-inflammatory cytokines.

RESUMO Objetivo Há evidências crescentes de que o estresse oxidativo e a inflamação estão envolvidos na perda de memória induzida pelo peptídeo beta-amilóide (βA). O ácido ursólico (AU), um composto triterpenóide, apresenta atividades anti-inflamatórias e antioxidantes potentes. Entretanto, não se sabe ainda se o AU atenua a neurotoxicidade induzida pelo βA. Método O agregado βA 25-35 foi administrado aos ratos por via intracerebroventricular. Resultados Observou-se que o AU reverteu significativamente os déficits de aprendizado e de memória induzidos pelo βA 25-35. Portanto, um dos potenciais mecanismos do efeito neuroprotetor seria a atenuação do acúmulo de malondialdeído e a depleção de glutationa no hipocampo induzidos pelo βA 25-35. Além disso, o AU suprimiu significativamente a supra regulação dos níveis de IL-1β, IL-6 e do fator de necrose tumoral α no hipocampo dos ratos tratados com βA 25-35. Conclusão Esses achados sugerem que o AU previne a perda de memória através da melhora do estresse oxidativo e da resposta inflamatória, podendoproporcionar uma nova estratégia terapêutica para o tratamento da doença de Alzheimer.

ABSTRACT Objective Increasing evidence demonstrates that oxidative stress and inflammatory are involved in amyloid β (Aβ)-induced memory impairments. Ursolic acid (UA), a triterpenoid compound, has potent anti-inflammatory and antioxidant activities. However, it remains unclear whether UA attenuates Aβ-induced neurotoxicity. Method The aggregated Aβ25-35 was intracerebroventricularly administered to mice. Results We found that UA significantly reversed the Aβ25-35-induced learning and memory deficits. Our results indicated that one of the potential mechanisms of the neuroprotective effect was attenuating the Aβ25-35-induced accumulation of malondialdehyde (MDA) and depletion of glutathione (GSH) in the hippocampus. Furthermore, UA significantly suppressed the upregulation of IL-1β, IL-6, and tumor necrosis-α factor levels in the hippocampus of Aβ25-35-treated mice. Conclusion These findings suggest that UA prevents memory impairment through amelioration of oxidative stress, inflammatory response and may offer a novel therapeutic strategy for the treatment of Alzheimer’s disease.