RESUMO
Protectin DX (PDX), a specialized pro-resolving lipid mediator, presents potential therapeutic applications across various medical conditions due to its anti-inflammatory and antioxidant properties. Since type-1 diabetes mellitus (T1DM) is a disease with an inflammatory and oxidative profile, exploring the use of PDX in addressing T1DM and its associated comorbidities, including diabetic neuropathic pain, depression, and anxiety becomes urgent. Thus, in the current study, after 2 weeks of T1DM induction with streptozotocin (60 mg/kg) in Wistar rats, PDX (1, 3, and 10 ng/animal; i.p. injection of 200 µl/animal) was administered specifically on days 14, 15, 18, 21, 24, and 27 after T1DM induction. We investigated the PDX's effectiveness in alleviating neuropathic pain (mechanical allodynia; experiment 1), anxiety-like and depressive-like behaviors (experiment 2). Also, we studied whether the PDX treatment would induce antioxidant effects in the blood plasma, hippocampus, and prefrontal cortex (experiment 3), brain areas involved in the modulation of emotions. For evaluating mechanical allodynia, animals were repeatedly submitted to the Von Frey test; while for studying anxiety-like responses, animals were submitted to the elevated plus maze (day 26) and open field (day 28) tests. To analyze depressive-like behaviors, the animals were tested in the modified forced swimming test (day 28) immediately after the open field test. Our data demonstrated that PDX consistently increased the mechanical threshold throughout the study at the two highest doses, indicative of antinociceptive effect. Concerning depressive-like and anxiety-like behavior, all PDX doses effectively prevented these behaviors when compared to vehicle-treated T1DM rats. The PDX treatment significantly protected against the increased oxidative stress parameters in blood plasma and in hippocampus and prefrontal cortex. Interestingly, treated animals presented improvement on diabetes-related parameters by promoting weight gain and reducing hyperglycemia in T1DM rats. These findings suggest that PDX improved diabetic neuropathic pain, and induced antidepressant-like and anxiolytic-like effects, in addition to improving parameters related to the diabetic condition. It is worth noting that PDX also presented a protective action demonstrated by its antioxidant effects. To conclude, our findings suggest PDX treatment may be a promising candidate for improving the diabetic condition per se along with highly disabling comorbidities such as diabetic neuropathic pain and emotional disturbances associated with T1DM.
Assuntos
Ansiedade , Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 1 , Ácidos Docosa-Hexaenoicos , Ratos Wistar , Animais , Masculino , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/psicologia , Ratos , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/psicologia , Ácidos Docosa-Hexaenoicos/farmacologia , Ácidos Docosa-Hexaenoicos/uso terapêutico , Ansiedade/tratamento farmacológico , Ansiedade/etiologia , Depressão/tratamento farmacológico , Depressão/etiologia , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Hiperalgesia/tratamento farmacológico , Comportamento Animal/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Córtex Pré-Frontal/efeitos dos fármacos , Neuropatias Diabéticas/tratamento farmacológicoRESUMO
Clinical and preclinical studies have shown that patients with Diabetic Neuropathy Pain (DNP) present with increased tumor necrosis factor alpha (TNF-α) serum concentration, whereas studies with diabetic animals have shown that TNF-α induces an increase in NaV1.7 sodium channel expression. This is expected to result in sensitization of nociceptor neuron terminals, and therefore the development of DNP. For further study of this mechanism, dissociated dorsal root ganglion (DRG) neurons were exposed to TNF-α for 6 h, at a concentration equivalent to that measured in STZ-induced diabetic rats that developed hyperalgesia. Tetrodotoxin sensitive (TTXs), resistant (TTXr) and total sodium current was studied in these DRG neurons. Total sodium current was also studied in DRG neurons expressing the collapsin response mediator protein 2 (CRMP2) SUMO-incompetent mutant protein (CRMP2-K374A), which causes a significant reduction in NaV1.7 membrane cell expression levels. Our results show that TNF-α exposure increased the density of the total, TTXs and TTXr sodium current in DRG neurons. Furthermore, TNF-α shifted the steady state activation and inactivation curves of the total and TTXs sodium current. DRG neurons expressing the CRMP2-K374A mutant also exhibited total sodium current increases after exposure to TNF-α, indicating that these effects were independent of SUMOylation of CRMP2. In conclusion, TNF-α sensitizes DRG neurons via augmentation of whole cell sodium current. This may underlie the pronociceptive effects of TNF-α and suggests a molecular mechanism responsible for pain hypersensitivity in diabetic neuropathy patients.
Assuntos
Gânglios Espinais/citologia , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Canal de Sódio Disparado por Voltagem NAV1.7/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Sumoilação , Fator de Necrose Tumoral alfa/metabolismo , Regulação para Cima , Animais , Comportamento Animal , Membrana Celular/metabolismo , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/metabolismo , Glucose/metabolismo , Hiperalgesia/sangue , Hiperalgesia/complicações , Ativação do Canal Iônico , Masculino , Proteínas Mutantes/metabolismo , Ratos Sprague-Dawley , Ratos Wistar , Fator de Necrose Tumoral alfa/sangueRESUMO
There have been several research studies on efficient methods for analysis and classification of electromyography (EMG) signals and adoption of wavelet functions, which is a promising approach for determining the spectral distribution of the signal. This study compares distinct time-frequency analysis methods for investigating the EMG activity of the thigh and calf muscles during gait among non-diabetic subjects and diabetic neuropathic patients. It also attempts to verify, by adaptive optimal kernel and discrete wavelet transform, whether there are EMG alterations related to diabetic neuropathy in the lower limb muscles during gait. The results show that diabetics might not keep up with the mechanical demands of walking by changing muscle fibre recruitment strategies, as seen in the control group. Moreover, principal components analysis indicates more alterations in diabetic motor strategies, and we identify that diabetic subjects need other strategies with different muscle energy production and frequencies to carry out their daily activities.