RESUMO
BACKGROUND: In over 300 million clinical cases, antidepressant drugs seem to provide only symptomatic relief and limited protection in life-threatening depressive events. OBJECTIVES: To compare neuronal-signaling mechanism and neuroprotective roles of Thymoquinone (TQ) suspension and its SLN (TQSLN) against standard antidepressant drug fluoxetine. METHODS: This research investigated in-silico docking at NF-KB p50 active site, CLSM based gut permeation, screening of antidepressant activities and neurosignaling pathways involved. RESULTS: As compared to fluoxetine, TQ reporteda significantly better docking score (-6.83 v/s -6.22) and a better lower free binding energy of (-34.715 Kcal/mol v/s -28.537 Kcal/mol). While poorly oral bioavailable and P-gp substrate TQ reported approximately 250% higher gut permeation if delivered as TQSLN formulation. In locomotor studies, as compared to TQS, TQSLN favored more prominent (p< 0.010) elevation in average time, horizontalactivity, average-velocity, and total-movement with reduced rest time LPS treated groups. However, in the tail suspension test, TQSLN significantly reduced immobility time (p<0.010). Similarly, In the modified force swimming test, TQSLN also significantly reduced immobility time (p<0.010), but swimming time (p<0.010) and climbing time (p<0.050) were significantly elevated. Subsequently, TQSLN reported significantly elevated neuroprotective BDNF (p<0.010) as well as hippocampal 5HT/TRP; accompanied with reduced levels of hippocampal inflammatory markers TNF-α (p<0.001) and IL-6 (p<0.010) as well as lower kynurenine and tryptophan ratio (KYN/TRP). Similarly, the hippocampal CA1 region further revealed TQSL more predominantly attenuated NF-kB nuclear translocation in the brain. CONCLUSION: Despite the poor bioavailability of TQ, TQSLN potentially attenuates neuroinflammatory transmitters and favors BDNF to modulate depressive neurobehavioral states.
Assuntos
Comportamento Animal/efeitos dos fármacos , Benzoquinonas/farmacologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Lipossomos/farmacologia , NF-kappa B/metabolismo , Neuroproteção/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Animais , Antidepressivos/farmacologia , Disponibilidade Biológica , Depressão/tratamento farmacológico , Depressão/metabolismo , Sistemas de Liberação de Medicamentos , Simulação de Acoplamento Molecular , Nanopartículas , Neuroimunomodulação/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Preparações de Plantas/farmacologia , Ratos , Fator de Necrose Tumoral alfa/metabolismoRESUMO
BACKGROUND: Chronic neuropathic pain is one of the most common and disabling symptoms in individuals with spinal cord injury (SCI). Over two-thirds of subjects with SCI suffer from chronic pain influencing quality of life, rehabilitation, and recovery. Given the refractoriness of chronic pain to most pharmacological treatments, the majority of individuals with SCI report worsening of this condition over time. Moreover, only 4-6% of patients in this cohort report improvement. Novel treatments targeting mechanisms associated with pain-maladaptive plasticity, such as electromagnetic neural stimulation, may be desirable to improve outcomes. To date, few, small clinical trials have assessed the effects of invasive and noninvasive nervous system stimulation on pain after SCI. OBJECTIVE: We aimed to review initial efficacy, safety and potential predictors of response by assessing the effects of neural stimulation techniques to treat SCI pain. SEARCH STRATEGY: A literature search was performed using the PubMed database including studies using the following targeted stimulation strategies: transcranial Direct Current Stimulation (tDCS), High Definition tDCS (HD-tDCS), repetitive Transcranial Magnetical Stimulation (rTMS), Cranial Electrotherapy Stimulation (CES), Transcutaneous Electrical Nerve Stimulation (TENS), Spinal Cord Stimulation (SCS) and Motor Cortex Stimulation (MCS), published prior to June of 2012. We included studies from 1998 to 2012. RESULTS: Eight clinical trials and one naturalistic observational study (nine studies in total) met the inclusion criteria. Among the clinical trials, three studies assessed the effects of tDCS, two of CES, two of rTMS and one of TENS. The naturalistic study investigated the analgesic effects of SCS. No clinical trials for epidural motor cortex stimulation (MCS) or HD-tDCS were found. Parameters of stimulation and also clinical characteristics varied significantly across studies. Three out of eight studies showed larger effects sizes (0.73, 0.88 and 1.86 respectively) for pain reduction. Classical neuropathic pain symptoms such as dysesthesia (defined as an unpleasant burning sensation in response to touch), allodynia (pain due to a non-painful stimulus), pain in paroxysms, location of SCI in thoracic and lumbar segments and pain in the lower limbs seem to be associated with a positive response to neural stimulation. No significant adverse effects were reported in these studies. CONCLUSIONS: Chronic pain in SCI is disabling and resistant to common pharmacologic approaches. Electrical and magnetic neural stimulation techniques have been developed to offer a potential tool in the management of these patients. Although some of these techniques are associated with large standardized mean differences to reduce pain, we found an important variability in these results across studies. There is a clear need for the development of methods to decrease treatment variability and increase response to neural stimulation for pain treatment. We discuss potential methods such as neuroimaging or EEG-guided neural stimulation and the development of better surrogate markers of response such as TMS-indexed cortical plasticity.