To investigate the effects of extremely-low-frequency PEMFs (pulsed electromagnetic fields) on the synthesis of epidermal collagen, six groups of animals each consisting of eight mature male rats were selected randomly: one group for the control and five for the test. Using a parallel set of Helmholtz coils, a uniform field intensity of 2 mT at different frequencies of 25, 50 and 100 Hz yielded the most effective frequency to be 25 Hz. Then, at this frequency, two different field intensities of 1 and 4 mT were applied. The treatment time of 2.5 h/day lasted for 8 days, keeping the same procedure for the control group, except with the field turned off. On the ninth day, the rats were killed and skin samples from the dorsal region were taken for collagen assessment by measuring hydroxyproline content using the Stegemann-Stalder [(1967) Clin. Chim. Acta 8, 267-273] method. The results indicated that a PEMF of 2 mT at 25 Hz increased the collagen synthesis (P < 0.05). The other intensities and frequency setting did not have any noticeable effect; however, at a frequency of 25 Hz at 4 mT, collagen increase was also noticed. It was concluded that at 25 Hz under a field setting of 2 mT for the duration of 8 days, stimulation of skin at 2.5 h/day would cause increase in collagen synthesis in rat skin.
Introduction: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) with unknown etiology. Neurotrophins are polypeptides belonging to the neurotrophic factor family. Neurotrophins mediate cell survival and proliferation in the nervous system. In this study, we determined the production of various neurotrophins, including brainderived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), and glial cell-derived neurotrophic factor (GDNF) in Cuprizone model of demyelination. Materials and Methods: In order to induce demyelination, animals were treated by Cuprizone. The mice were divided into three groups. The first group was treated by Cuprizone for 5 weeks. The second group was treated by Cuprizone for 5 weeks and normal diet for 1 week. The third (control) group received normal diet for 6 weeks. After the mice were sacrificed, cerebral corpus callosum was removed and evaluated for expression of neurotrophic factors by real time PCR and histological evaluation. Results: After five weeks, we detected a significant increase of BDNF and GDNF compared to the control group. No changes were observed in CNTF expression. After six weeks, expression of BDNF and GDNF were decreased but they had still higher levels compared to control group. Conclusion: This study suggests that neurotrophins may play a role in pathogenesis of MS.
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