Effects of supraphysiological doses of nandrolone decanoate in achilles tendon of rats

Abstract

Background. Anabolic androgenic steroids (AAS) are a group of natural compounds derived from testosterone. It promotes a rapid increase in muscle mass as well as an individual’s strength, thus overloading the locomotor system. Injuries, such as tearing of ligaments and tendons and damaged cartilage, are described among users of these steroids. Methods. To study the effects of nandrolone decanoate (ND) on tendons, male adult Wistar rats were distributed in G1 - control group; G2 - sedentary animals treated with ND; G3 - trained animals; G4 - trained animals treated with DN. After 8 weeks of treatment, the animals were submitted to euthanasia and the tendon was removed for further analyzes. Results. Non-collagenous protein quantification showed a significant decrease in G3 and G4. Zymography indicated an increase in the latent and intermediate isoforms (72 kDa and 68 kDa respectively) of MMP-2 in the same groups, along with a tissue disorganization and a high cellularity revealed through hematoxylin-eosin stains. Polarization microscopy and birefringence analysis revealed that all experimental groups presented a significant disorganization of collagen fibers when compared to control. Conclusion. In this way we believe the chronic use of AAS leads to tissue disorganization, thus increasing the chance of tendon rupture.