Modelo experimental de indução à tendinose de Aquiles: um estudo morfométrico

Abstract

Background: Microscopically, tendinosis presents collagen fibers disorganization and microtears, hipercellularity, higher collagen type III and glicosaminoglicans deposition. Purpose: Morphometric evaluation of the Aquiles tendinosis` pathogen events and evolution, using a male rats induction model. Methods: Thirty male Wistar rats were randomized splitted in an experimental (n=15) and a control groups (n=15). Five animals/group were euthanized at four, eight and sixteen weeks. Experimental group ran on an adapted treadmill 5 times a week, 80minutes daily, at 26.8 m/min. Then, the right and left Achilles tendons were collected and processed. Obtained slides were stained by Hematoxilyn-Eosin, Picrosirius Red, Alcian Blue, AgNOR and TUNEL.Results: Cellular density and microtearing raised in the experimental group at fourth (0.92 ± 0.06 vs 0.61 ± 0.05 - P<0.01) (9.93 ± 1.55 vs 3.7 ± 0.79 - P<0.01), eighth (0.85 ± 0.04 vs 0.58 ± 0.06 - P<0.05) (11.6 ± 2.59 vs 3.81 ± 0.87 - P<0.01) and sixteenth (0.82 ± 0.04 vs 0.53 ± 0.06 - P<0.01) (12.13 ± 1.03 vs 4.44 ± 0.56 - P<0.001) weeks, respectively. There were more type III collagen and glycosaminoglycans deposition in the experimental group at fourth (43.4 ± 3.84 vs 6.57 ± 3.06 - P<0.001) (8.33 ± 1.17 vs 3.97 ± 0.71 - P<0.01), eighth (50.45 ± 4.2 vs 6.71 ± 2.84 - P<0.0001) (9.12 ± 1.17 vs 4.19 ± 0.75 - P<0.01) and sixteenth (59.6 ±2.41 vs 4.96 ± 1.32 - P<0.0001) (12.53 ± 1.56 vs 3.84 ± 0.66 - P<0.01) weeks, respectively. The cellular activity expression was higher in the experimental groups (4 clusters/nucleus vs 2 clusters/nucleus - P<0.0001) of all time intervals. Conclusions: The proposed model was able to induce degenerative injury and morphometry showed important results. Future researches must investigate physical and pharmacological therapies effects to the Achilles tendinosis.