AvaliaÃÃo morfomÃtrica da regeneraÃÃo nervosa perifÃrica em animais desnutridos precocemente

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The study evaluated the peripheral nerve regeneration in adult animals that were submitted to protein malnutrition during the period known as the critical window of development. We used 20 male rats, adult, Wistar line. During the period of lactation, parts of the mothers received diet hypoproteic (casein 8%) forming the group of malnourished pups (10 animals), while another part has received normal diet (casein 17%), forming the group of nourished pups (10 animals) . After this period, the animals were fed with standard diet until the end of the experiment, without restrictions of water and food. The evolution of weight was recorded daily for 21 days, and after this period registered at 30, 60, 90 and 210 days. At 90 days, the animals (05 per group) were pre-anesthetized with atropine and anesthetized with a solution of chloride of ketamine (50 mg) and Xilasina to 2% (20 mg) (0.2 mL/100g). The sciatic nerve was cut about 1 cm above the bifurcation of the posterior tibial nerve and common fibular. After the injury, nerve fragments were sutured to a tube of polyethylene (10 mm) filled with saline and matrigel. According to the presence or absence of nerve injury, the animals were divided into groups Nourished Without Injury (GNSL), Nourishing Injuriated (GNL), Undernourished Without Injury (GDSL) and Undernourished injuriated (GDL). One hundred and twenty days after the nerve injury was collected the neoformed nervous tissue, fixed at Karnowisky solution for 24h at 4  C, post-fixed with solution of osmium tetroxide and processed to obtain semi-thin slices (0.5 nm), stained with toluidine blue,. We evaluated the cross-sectional area of the sciatic nerve, the quantity, type and density of nerve fibers myelin and the total number of blood vessels. Statistical analysis was performed using the average of the values  standard deviation and Student T test for parametric data, and the median value  standard error test and U test Mann-Whitney for non parametric data, and 0.05. Body weight remained low from the 3rd day of life and throughout the experiment in group malnourished. There were no differences of the parameters analyzed between groups GNSL and GDSL. There was an increase in the number of vessels in the GDL (p = 0.0022) compared to GNL. The group GNSL on the GNL showed greater cross-sectional area (p = 0.0002), increased amount of myelin fibers (p = 0004), lower fiber density (p = 0009) and greater proportion of fibers with intermediate size (p <0.05), however there was a smaller amount of blood vessels (p = 0.01). The GDL showed regenerative similar pattern in relation to GNL. In light of these results, we can conclude that in adult animals subjected to protein malnutrition during the lactation, with subsequent period of nutritional replacement, no changes in the structure of the peripheral nervous tissue, and regenerative response in the face of this tissue injury, after 120 days of injury

ASSUNTO(S)

peripheral nerve regeneration  protein malnutrition nervo ciÃtico desnutriÃÃo protÃica regeneraÃÃo nervosa perifÃrica ciencias da saude pciatic nerve

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