Histologic and Biomechanical Evaluation of the Effects of Social Stress and the Antidepressant Fluoxetine on Tendon Healing in Rats

Abstract

Impaired wound healing in humans under psychological stress and the positive effects of antidepressant drugs on wound healing were also shown in the literature. However, there are currently no studies regarding the effects of antidepressant drugs on tendon healing. The aim of this study was to compare tendon healing under normal conditions versus social stress. We also aimed to perform a histological and biomechanical analysis of the effects of the antidepressant drug fluoxetine on tendon healing. Sixty Sprague Dawley rats were divided into six groups. A social stress regimen was used to stress the rats. The use of fluoxetine in the social stress group yielded significantly better biomechanical results and the collagen organizations of the fluoxetine group were more similar to the normal tendon collagen organization. Fluoxetine seems to inhibit the negative effects of stress on tendon healing and seems to improve tendon healing. Levels of Evidence: Level 5

Disrupted development from head to tail: Pervasive effects of postnatal restricted resources on neurobiological, behavioral, and morphometric outcomes

“…In addition to shorter tails observed in LR animals, preliminary observations of shorter foot lengths in LR rats were observed in the current study, an observation that deserves further investigation. It is also important to note that, while stress and anxiety have been shown to negatively affect musculoskeletal tissue health and maturation (Ozturk et al, 2015;Foertsch et al, 2017;Wuertz-Kozak et al, 2020), musculoskeletal development is also well documented to be driven by mechanical stimulations, with reduction or removal of mechanical cues during development-resulting in 10.3389/fnbeh.2022.910056 underdeveloped musculoskeletal tissues (Connizzo et al, 2013;Galloway et al, 2013;Andarawis-Puri et al, 2015;Arvind and Huang, 2017). Therefore, it is difficult to separate whether the differences observed in musculoskeletal development in this study are attributable to varying neurobiological responses or mechanical loading environments, due to differences in bedding, mobility, body weight, or degree of play.…”

“…Skeletal effects were also observed in mice exposed to social stress as adolescents; specifically, microcomputed tomography (micro-CT) and histomorphometric analyses indicated reduced length of the tibia and femur bones, as well as altered growth plate thickness and mineral deposition levels (Foertsch et al, 2017). Stress has also been reported to have a negative impact on tendons, a consequential effect considering that tendons serve as a mechanical link between the muscle and bone, and are critical for adaptive movement (Ozturk et al, 2015). Importantly, tendons are known to adapt to changing mechanical environments in a similar fashion as bone tissue (Maganaris et al, 2017).…”