Endurance training induces structural and morphoquantitative changes in rat vagus nerve

Abstract

Introduction: Many nervous system tissues and cells suffers positive changes when faced to exercise training. However, data on vagus nerve adaptation from exercise-induced study is absent. Objective: To analyze the effect of an endurance training on the vagus nerve morphology of rats. Methods: Wistar rats (6 months of age) were divided into two groups: control group (CG, n=8), and aerobic trained group (AT, n=8). AT was submitted to a treadmill training program of five times per week during 12 weeks. The maximum speed stipulated in the training protocol corresponded to 60% of the mean maximum intensity achieved by the group in the test of maximum effort. Results: Twelve weeks of treadmill training resulted in left ventricular hypertrophy in the AT group compared to CG. There was a significant increase in the area of both the myelinated and unmyelinated axons, and in the area of myelin sheath with training. The number of neurotubules and neurofilaments in myelinated fibers of aerobic trained group was significantly greater than CG (p≤0.05). Conclusion: Endurance training promoted significant increase in morphometric parameters of the vagus nerve in the same way it affect somatic nerves.

Aging Induces Changes in the Somatic Nerve and Postsynaptic Component without Any Alterations in Skeletal Muscles Morphology and Capacity to Carry Load of Wistar Rats

“…After selection of the fields in the semi-thin sections, the ultra-thin sections were obtained with a diamond knife, in ultramicrotome (Sorvall MT-2), and contrasted with uranyl acetate and lead citrate, finally being analyzed by the transmission electron microscope. The techniques employed here, were in agreement with other publications done by our research group (Pianca et al, 2015 ; Carbone et al, 2017 ; Krause Neto et al, 2017b ).…”

“…After an incision, a fragment of ~0.5 cm in length from the tibial nerve was removed from the posterior portion of the right leg. Then, we fixed the nerve fragment in 2.5% glutaraldehyde solution in phosphate buffer (0.2 M, pH 7.3) for 3 h (Pianca et al, 2015 ; Carbone et al, 2017 ; Krause Neto et al, 2017b ). Subsequently, we washed the material three times with the same buffer solution for 5 min at a time.…”

“…The material remained in this stage for 5 h and then left in the same resin at 60°C for a further 3 days period. After completion of the material preparation procedure, semi-thin sections were done, the histological slides prepared and the tissue stained with toluidine blue (Ceballos et al, 1999 ; Pianca et al, 2015 ). After selection of the fields in the semi-thin sections, the ultra-thin sections were obtained with a diamond knife, in ultramicrotome (Sorvall MT-2), and contrasted with uranyl acetate and lead citrate, finally being analyzed by the transmission electron microscope.…”

“…Both stereological techniques are used in our laboratory to quantify various outcomes in nerves and other tissues (Pianca et al, 2015 ; Krause Neto and Gama, 2017 , and Krause Neto et al, 2017b ).…”