Ação da proteína sericina em lesão nervosa isquiática, associada ao exercício físico de natação, em ratos wistar

Abstract

Lesions in the peripheral nervous system imply active in voluntary motor function, leading to increased morbidity, incapacities in work activities and daily life, with consequent increase in costs for the public health system. Effective treatments research, studies have shown that physical and efficient exercise in functional recovery after the development of the nervous system, which is not a process of nerve regeneration. In addition, several products are being investigated with no intention to aid recovery, there are no cases of sericin silk protein, studies indicate its action in the healing process, contributing in the tissue regeneration in chronic lesions. The aim of this study was to verify the role of sericin associated with a swimming exercise protocol, with overload, without repair of the sciatic nerve of Wistar rats after nerve compression. For this purpose, 80 animals were divided into five groups of 16 animals each, being: control (CON), Injury (LES), injury-sericin (LSER), injury-swimming (LNAT) and injury-sericin-swimming (LSRNT). The animals of the LES, LSER, LNAT and LSRNT groups were submitted to compression of the sciatic nerve, however LSER and LSRNT received an application of hydrolyzed sericin protein directly on a nerve lesion at the time of surgery. The LNAT and LSRNT groups underwent swimming exercise with a load of 10% of the body weight of the animal, for cycles of five days of training and two of rest, of 1 or 3 cycles, according to the euthanasia times, and with progression of time, being in the first cycle 15 minutes of exercise, in the second 20 minutes and 25 minutes in the third cycle. During the experimental period, animals as well as nociception, by the digital "Von Frey" filament test and function analysis by means of the functional index of the ischiatic. Euthanasia was performed in two stages, the sample being euthanized on the 8th postoperative day, and the remainder on the 22nd day. Two fragments of the nerve, distal to the nerve injury, were collected and prepared for light microscopy analysis, stained with hematoxylin-eosin and pre-stained with carbon tetraoxide, being observed as morphological and morphometric characteristics of the nerve fiber. The results were analyzed statistically as their normality and one-way ANOVA was performed, with LSD post-test. Regarding the euthanized animals on the eighth day, a sericin applied directly on the sciatic nerve lesion, presented proinflammatory characteristics, and an isolated swimming showed an improvement of hypernociception in relation to the other interventions. There were no signs of acceleration of the nerve repair process on the eighth day after injury. In relation to the euthanized animals on the 22nd day, an association of sericin and swimming treatment evidenced a regulating effect of the serinin pro-inflammatory action by the resisted swimming exercise, and an isolated sericin caused exacerbation of the inflammatory process and resistance swimming exercise, It showed good evolution to the nociceptive threshold and allodynia.