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OBJECTIVES: The aim of this study, conducted at the Military Institute of Hygiene and Epidemiology in Warsaw in 2017, was to evaluate the effects of a single (15 min) and repeated (5 times for 15 min) radio-frequency radiation (RFR) exposure of 1800 MHz frequency on the analgesic efficacy of morphine in healthy rats and rats with complete Freund's adjuvant (CFA) induced inflammation. MATERIAL AND METHODS: Rats were injected intraperitoneally with morphine (MF) in the dose of 8 mg/kg or drug vehicle 15 min before RFR exposure. The authors used the plantar analgesia meter and the radiant heat paw-withdrawal test to assess the pain threshold. RESULTS: A single RFR exposure slightly influenced paw withdrawal latency (PWL) in healthy rats in the single exposure baseline group, and influenced PWL, 30 and 60 min after morphine or vehicle injection, in the repeated exposure group. There were differences between the sham-exposed groups (vehicle), 30, 60 and 90 min after injection, both in the single and repeated RFR-exposure groups. The antinociceptive effect of morphine in healthy rats was slightly decreased by RFR exposure at 60 and 90 min, both in the single and repeated exposure groups. The PWL was slightly decreased, both in the single and repeated exposure groups with inflammation (CFA and CFA/MF), at 30, 60 and 90 min, and PWL was increased in the sham-exposed groups (CFA and CFA/MF), both in the single and repeated exposure groups, at 30, 60 and 90 min. The antinociceptive effect of morphine in healthy rats was significantly increased by RFR exposure at 30 min after drug injection in the single exposure group, and increased at 30 and 60 min in the repeated exposure group. CONCLUSIONS: The authors observed a minor influence of RFR exposure on the antinociceptive effects of morphine in healthy rats after repeated exposures and a statistically significant influence of repeated exposure on morphine mediated antinociceptive effects in the inflammation group. Int J Occup Med Environ Health. 2019;32(4):465-74.

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This study aimed the development of nanocapsules (NCs) for oral indole-3-carbinol (I3C) administration and evaluation of antinociceptive potential of this compound in its two forms, free and nanoencapsulated, using acute pain models. NCs showed adequate physicochemical characteristics and protected the I3C against UVC radiation exposure. It was observed no chemical bond between I3C and polymer by FTIR. Besides, X-ray and DSC analysis suggested that I3C was molecularly dispersed in NCs. The dialysis bag technique showed that almost 100% of the compound was released from NCs at 360min. Mathematical modeling demonstrated that this release occurred in two rates, with an initial burst effect followed by a slower release of I3C. Regarding the in vivo analysis, time-response curve showed that both forms of I3C caused an inhibition in inflammatory phase of nociception induced by formalin and increased the latency response in hot plate test. Interestingly, NCs were able to prolong the I3C effect in both tests. Furthermore, in dose-response curve, only I3C in its nanoencapsulated form presented effect on inflammatory phase of the formalin test. In conclusion, NCs to I3C incorporation presented adequate nanometric characteristics and prolonged its antinociceptive action in acute pain models tested.

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O objetivo deste estudo foi comparar os efeitos analgésicos das freqüências de base da corrente interferencial em pacientes com lombalgia resultante de osteoartrose. Foram selecionados 14 indivíduos,de ambos os gêneros, atendidos em 06 sessões, durante 02 semanasno setor de Fisioterapia do Hospital da Universidade Católica deBrasília (HUCB). Os mesmos foram distribuídos de forma aleatória em dois grupos: um que recebeu a eletroestimulação com freqüênciade 4000 Hz e outro de 2000 Hz; os demais parâmetros utilizados foram os mesmos para ambos os grupos: freqüência de amplitudemodulada (AMF) de 25 Hz e duração de 25 minutos. A análise comparativa foi realizada através da Escala Visual Analógica (EVA) e por meio de dois questionários de incapacitação funcional pela lombalgia: o Revised Oswestry Pain Questionnaire e o Roland-MorrisDisability Questionnaire. Os resultados demonstraram uma melhora signifi cativa da lombalgia ao comparar os momentos pré-tratamentoe pós-tratamento das duas freqüências de base, tanto em relação à EVA, quanto aos questionários. Não foi encontrada diferença significativa do efeito analgésico entre as duas freqüências de base.

The aim of this study was to compare the analgesic effects of the interferential therapy current frequencies in patients with low backpain from osteoarthrosis. Fourteen patients from both genders were selected and submitted to six physical therapy sessions, for two weeksat Universidade Católica de Brasilia Hospital. They were randomly distributed into two groups: one with the electrical stimulation with frequency of 4000 Hz and other with 2000 Hz; the other parameters were the same for both groups: amplitude modulated frequency(AMF) of 25 Hz, for 25 minutes. The comparative analysis was carried out using the analogue visual scale and two questionnaires for low back pain functional disability: the Revised Oswestry PainQuestionnaire and the Roland-Morris Disability Questionnaire. Results showed a signifi cant low back pain reduction when pretreatment and pos-treatments were compared to the analogue visual scale and both questionnaires. There was no difference of the analgesic effect between the two current frequencies.

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Relatively weak, extremely low frequency (ELF), magnetic fields have been shown to exert a variety of biological effects, although the modes of action remain to be established. Neuroactive steroids and neurosteroids have been shown to produce a diverse range of rapid centrally mediated behavioral and physiological effects that are reported to be sensitive to magnetic fields. Here we show that brief exposure of male mice to an ELF magnetic field (30 min, 60 Hz, 141 microT peak) significantly reduces the analgesic effects arising from intracerebroventricular (i.c.v.) administration of the centrally produced allylic neuroactive steroid, 3alpha-hydroxy-4-pregnen-20-one (3alphaHP) and that the dihydropyridine (DHP) calcium channel antagonists, diltiazem and nifedipine, block the inhibitory effects of the 60 Hz ELF on 3alphaHP-induced analgesia. These results indicate that exposure to 60 Hz ELF affects the analgesic effects of neuroactive steroids such as 3alphaHP through alterations in calcium channel function. These findings raise the possibility that ELF magnetic fields may, in part, exert their actions through effects on diverse neuroactive steroid modulated processes.

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