Transcranial direct current stimulation is more effective than pregabalin in controlling nociceptive and anxiety-like behaviors in a rat fibromyalgia-like model.

OBJECTIVES: Despite the fact that fibromyalgia, a widespread disease of the musculoskeletal system, has no specific treatment, patients have shown improvement after pharmacological intervention. Pregabalin has demonstrated efficacy; however, its adverse effects may reduce treatment adherence. In this context, neuromodulatory techniques such as transcranial direct current stimulation (tDCS) may be employed as a complementary pain-relieving method. Consequently, the purpose of this study was to evaluate the effect of pregabalin and tDCS treatments on the behavioral and biomarker parameters of rats submitted to a fibromyalgia-like model. METHODS: Forty adult male Wistar rats were divided into two groups: control and reserpine. Five days after the end of the administration of reserpine (1 mg/kg/3 days) to induce a fibromyalgia-like model, rats were randomly assigned to receive either vehicle or pregabalin (30 mg/kg) along with sham or active- tDCS treatments. The evaluated behavioral parameters included mechanical allodynia by von Frey test and anxiety-like behaviors by elevated plus-maze test (time spent in opened and closed arms, number of entries in opened and closed arms, protected head-dipping, unprotected head-dipping [NPHD], grooming, rearing, fecal boluses). The biomarker analysis (brain-derived neurotrophic factor [BDNF] and tumor necrosis factor-α [TNF-α]) was performed in brainstem and cerebral cortex and in serum. RESULTS: tDCS reversed the reduction in the mechanical nociceptive threshold and the decrease in the serum BDNF levels induced by the model of fibromyalgia; however, there was no effect of pregabalin in the mechanical threshold. There were no effects of pregabalin or tDCS found in TNF-α levels. The pain model induced an increase in grooming time and a decrease in NPHD and rearing; while tDCS reversed the increase in grooming, pregabalin reversed the decrease in NPHD. CONCLUSIONS: tDCS was more effective than pregabalin in controlling nociception and anxiety-like behavior in a rat model-like fibromyalgia. Considering the translational aspect, our findings suggest that tDCS could be a potential non-pharmacological treatment for fibromyalgia.

The Application of Static Magnetic Stimulation Reduces Survival of SH-SY5Y Neuroblastoma Cells.

BACKGROUND/AIM: Central nervous system cancer is still a major public health issue. The effectiveness of treatments is limited and varies depending on the severity of disease. Therefore, there is a demand for the development of novel therapies. Static magnetic stimulation (SMS) emerges as a new therapeutic option. The aim of this study was to evaluate the SMS effects on neuroblastoma cells in culture. MATERIALS AND METHODS: SH-SY5Y neuroblastoma cells were exposed to 0.3T SMS for 6, 12, 24, 36, 72 h, and 6 days. Cell viability (MTT), cell death (annexin-V/PI staining) and cell cycle (DNA content), cell proliferation (CFSE), autophagy (acridine orange), and total mitochondrial mass (MitoTracker™ Red) were analyzed to establish the cellular response to SMS. RESULTS: The viability of SH-SY5Y cells was reduced after exposure to SMS for 24 h and 6 days (p<0.05), without differences for the other times (p>0.05); however, this effect was not related to cell death or cell cycle arrest (p>0.05). In contrast, the viability of human malignant melanoma (HMV-II) cells, used as a tumoral control, was not affected. In addition, stimulated SH-SY5Y cells presented a decrease in mitochondrial mass at both exposure times and a reduction in autophagy and cell proliferation after 6 days (p<0.05). CONCLUSION: SMS application appears to be a promising adjuvant therapy for the treatment of neuroblastoma since it decreases the survival of SH-SY5Y neuroblastoma cells.

A3 receptor agonist modulates IL-1ß hippocampus levels in a rat model of neuropathic pain

Introduction: Considering the lack of specific treatments for neuropathic pain, this study aimed to evaluate the effect of a single dose of adenosine A3 receptor IB-MECA on inflammatory and neurotrophic parameters in rats subjected to a neuropathic pain model. Methods: 64 adult male Wistar rats were used. Neuropathic pain was induced by chronic constriction injury (CCI) of the sciatic nerve and the treatment consisted of a 0.5 µmol/kg dose of IB-MECA, a selective A3 adenosine receptor agonist, dissolved in 3% DMSO; vehicle groups received DMSO 3% in saline solution, and morphine groups received 5 mg/kg. Cerebral cortex and hippocampus IL-1ß, BDNF, and NGF levels were determined by Enzyme-Linked Immunosorbent assay. Results: The main outcome was that a single dose of IB-MECA was able to modulate the IL-1ß hippocampal levels in neuropathic pain induced by CCI and the DMSO increased IL-1ß and NGF hippocampal levels in sham-operated rats. However, we did not observe this effect when the DMSO was used as vehicle for IB-MECA, indicating that IB-MECA was able to prevent the effect of DMSO. Conclusions: Considering that the IL-1ß role in neuropathic pain and the contributions of the hippocampus are well explored, our result corroborates the relationship between the A3 receptor and the process of chronic pain maintenance.

Repetitive Transcranial Magnetic Stimulation (rTMS) Reverses the Long-term Memory Impairment and the Decrease of Hippocampal Interleukin-10 Levels, both Induced by Neuropathic Pain in Rats.

Neuropathic pain (NP) is characterized by the presence of spontaneous pain, allodynia and hyperalgesia. Repetitive transcranial magnetic stimulation (rTMS) is one of neuromodulatory techniques that induces satisfactory NP relief, including that from refractory pain patients. The objective of this study was to evaluate rTMS treatment over long term memory (LTM) and hippocampal BDNF and IL-10 levels in rats submitted to a NP model. A total of 81 adult (60-days old) male Wistar rats were randomly allocated to one of the following 9 experimental groups: control, control + sham rTMS, control + rTMS, sham neuropathic pain, sham neuropathic pain + sham rTMS, sham neuropathic pain + rTMS, neuropathic pain (NP), neuropathic pain + sham rTMS and neuropathic pain + rTMS. Fourteen days after the surgery for chronic constriction injury (CCI) of the sciatic nerve, NP establishment was accomplished. Then, rats were treated with daily 5-minute sessions of rTMS for eight consecutive days. LTM was assessed by the object recognition test (ORT) twenty-four hours after the end of rTMS treatment. Biochemical assays (BDNF and IL-10 levels) were performed in hippocampus tissue homogenates. rTMS treatment reversed the reduction of the discrimination index in the ORT and the hippocampal IL-10 levels in NP rats. This result shows that rTMS reverses the impairment LTM and the increase in the hippocampal IL-10 levels, both induced by NP. Moreover, it appears to be a safe non-pharmacological therapeutic tool since it did not alter LTM and neurochemical parameters in naive animals.

rTMS induces analgesia and modulates neuroinflammation and neuroplasticity in neuropathic pain model rats.

Neuropathic pain (NP) is related to the presence of hyperalgesia, allodynia, and spontaneous pain, affecting 7%-10% of the general population. Repetitive transcranial magnetic stimulation (rTMS) is applied for NP relief, especially in patients with refractory pain. As NP response to existing treatments is often insufficient, we aimed to evaluate rTMS treatment on the nociceptive response of rats submitted to an NP model and its effect on pro-and anti-neuroinflammatory cytokine and neurotrophin levels. A total of 106 adult male Wistar rats (60 days old) were divided into nine experimental groups: control, control + sham rTMS, control + rTMS, sham NP, sham neuropathic pain + sham rTMS, sham neuropathic pain + rTMS, NP, neuropathic pain + sham rTMS, and neuropathic pain + rTMS. NP establishment was achieved 14 days after the surgery to establish chronic constriction injury (CCI) of the sciatic nerve. Rats were treated with 5 min daily sessions of rTMS for eight consecutive days. Nociceptive behavior was assessed using von Frey and hot plate tests at baseline, after NP establishment, and post-treatment. Biochemical assays to assess the levels of brain-derived neurotrophic factor (BDNF), tumor necrosis factor-alpha (TNF-α), and interleukin (IL)-10, were performed in the prefrontal cortex (PFC) and spinal cord tissue homogenates. rTMS treatment promoted a partial reversal of mechanical allodynia and total reversal of thermal hyperalgesia induced by CCI. Moreover, rTMS increased the levels of BDNF, TNF-α, and IL-10 in the PFC. rTMS may be a promising tool for the treatment of NP. The alterations induced by rTMS on neurochemical parameters may have contributed to the analgesic effect presented.

tDCS and exercise improve anxiety-like behavior and locomotion in chronic pain rats via modulation of neurotrophins and inflammatory mediators.

Anxiety disorders cause distress and are commonly found to be comorbid with chronic pain. Both are difficult-to-treat conditions for which alternative treatment options are being pursued. This study aimed to evaluate the effects of transcranial direct current stimulation (tDCS), treadmill exercise, or both, on anxiety-like behavior and associated growth factors and inflammatory markers in the hippocampus and sciatic nerve of rats with neuropathic pain. Male Wistar rats (n = 216) were subjected to sham-surgery or sciatic nerve constriction for pain induction. Fourteen days following neuropathic pain establishment, either bimodal tDCS, treadmill exercise, or a combination of both was used for 20 min a day for 8 consecutive days. The elevated plus-maze test was used to assess anxiety-like behavior and locomotor activity during the early (24 h) or late (7 days) phase after the end of treatment. BDNF, TNF-ɑ, and IL-10 levels in the hippocampus, and BDNF, NGF, and IL-10 levels in the sciatic nerve were assessed 48 h or 7 days after the end of treatment. Rats from the pain groups developed an anxiety-like state. Both tDCS and treadmill exercise provided ethological and neurochemical alterations induced by pain in the early and/or late phase, and a modest synergic effect between tDCS and exercise was observed. These results indicate that non-invasive neuromodulatory approaches can attenuate both anxiety-like status and locomotor activity and alter the biochemical profile in the hippocampus and sciatic nerve of rats with neuropathic pain and that combined interventions may be considered as a treatment option.

Antinociceptive and neurochemical effects of a single dose of IB-MECA in chronic pain rat models.

This study aimed to evaluate the effect of a single administration of IB-MECA, an A3 adenosine receptor agonist, upon the nociceptive response and central biomarkers of rats submitted to chronic pain models. A total of 136 adult male Wistar rats were divided into two protocols: (1) chronic inflammatory pain (CIP) using complete Freund's adjuvant and (2) neuropathic pain (NP) by chronic constriction injury of the sciatic nerve. Thermal and mechanical hyperalgesia was measured using von Frey (VF), Randal-Selitto (RS), and hot plate (HP) tests. Rats were treated with a single dose of IB-MECA (0.5 µmol/kg i.p.), a vehicle (dimethyl sulfoxide-DMSO), or positive control (morphine, 5 mg/kg i.p.). Interleukin 1ß (IL-1ß), brain-derived neurotrophic factor (BDNF), and nerve growth factor (NGF) levels were measured in the brainstem and spinal cord using enzyme-linked immunosorbent assay (ELISA). The establishment of the chronic pain (CIP or NP) model was observed 14 days after induction by a decreased nociceptive threshold in all three tests (GEE, P < 0.05). The antinociceptive effect of a single dose of IB-MECA was observed in both chronic pain models, but this was more effective in NP model. There was an increase in IL-1ß levels promoted by CIP. NP model promoted increase in the brainstem BDNF levels, which was reversed by IB-MECA.

Transcranial direct current stimulation combined with exercise modulates the inflammatory profile and hyperalgesic response in rats subjected to a neuropathic pain model: Long-term effects.

BACKGROUND: Behavioral alterations, like mechanical and thermal hyperalgesia, and modulation of biomarkers in the peripheral and central nervous systems (CNS) are markers of chronic pain. Transcranial direct current stimulation (tDCS) with exercise is a promising therapy for pain due to its neuromodulatory capacity. OBJECTIVE: To assess the individual effects of tDCS, exercise, and the two combined on the nociceptive response and BDNF, IL-1ß, and IL-4 levels in the CNS structures of rats in a chronic pain model. METHODS: For 8 consecutive days after the establishment of chronic neuropathic pain by inducing a constriction injury to the sciatic nerve (CCI), the rats received tDCS, exercise, or both treatments combined (20 min/day). The hyperalgesic response was assessed by von Frey and hot plate tests at baseline, 7, and 14 days after CCI surgery and immediately, 24 h, and 7 days after the end of treatment. The BDNF, IL-1ß, and IL-4 levels were assessed in the cerebral cortex, brainstem, and spinal cord by enzyme-linked immunosorbent assay at 48 h and 7 days after the end of treatment. RESULTS: The CCI model triggered marked mechanical and thermal hyperalgesia. However, bimodal tDCS, aerobic exercise, and the two combined relieved nociceptive behavior for up to 7 days following treatment completion. CONCLUSIONS: Bimodal tDCS, aerobic exercise, or both treatments combined promoted analgesic effects for neuropathic pain. Such effects were reflected by cytokine modulation throughout the spinal cord-brainstem-cerebral cortex axis.

Tissue-engineered solution containing cells and biomaterials-an in vitro study: A perspective as a novel therapeutic application.

Some biomaterial scaffolds can positively interfere with tissue regeneration and are being developed to successfully repair the tissue function. The possibility of using epithelial cells combined with biomaterials appears to be a new option as therapeutic application. This combination emerges as a possibility for patients with Mayer-Rokitansky-Kuster-Hauser syndrome which requires vaginal repair and can be performed with tissue-engineered solution containing cells and biomaterials. It is expected that tissue-engineered solution containing cells and biomaterials would promote tissue repair in a more efficient, modern, and safe way. This study tested the efficiency of tissue-engineered solution containing human malignant melanoma cell line (HMV-II) and different biomaterials, including Cellprene®, Membracel®, and poly lactic-co-glycolic acid/epoxidized polyisoprene. The cells adhered better on poly lactic-co-glycolic acid/epoxidized polyisoprene, and it was found that tissue-engineered solution may also contain mesenchymal stem cells cultivated on poly lactic-co-glycolic acid/epoxidized polyisoprene. Histological, immunofluorescence, and scanning electron microscopy analyses were performed. These initial in vitro results suggest that tissue-engineered solution containing cells and poly lactic-co-glycolic acid/epoxidized polyisoprene is a potential for tissue reconstruction.

Effect of Helicobacter pylori on NFKB1, p38α and TNF-α mRNA expression levels in human gastric mucosa.

Helicobacter pylori infects ~50% of the world population, causing chronic gastritis and other forms of cellular damage. The present study assessed the influence of H. pylori on the mRNA expression levels of nuclear factor-κB1 (NFKB1), p38α and tumor necrosis factor-α (TNF-α) in human gastric mucosa in a southern Brazilian population. Human gastric tissue was collected by upper endoscopy and H. pylori diagnosis was performed using a rapid urease test and histological analysis. Total RNA was extracted and purified for subsequent cDNA synthesis and analysis by quantitative polymerase chain reaction (qPCR). The gastric tissue samples were divided into four groups as follows: Normal, inactive chronic gastritis, active chronic gastritis and intestinal metaplasia. The SDHA gene was classified as the most stable when compared with ACTB, GAPDH, B2M and HPRT1 genes, and was therefore selected as the reference gene for qPCR data normalization. TNF-α mRNA expression was significantly higher in samples that were positive for H. pylori and with active chronic gastritis. However, no difference was detected in the mRNA expression levels of NFKB1 and p38α between the groups. The present study concluded that the presence of H. pylori is associated with TNF-α upregulation in human gastric mucosa, but had no effect on NFKB1 and p38α mRNA expression levels.