Rat Tenocytes

In Vitro Tenocyte-Protective Effectiveness of Dehydroepiandrosterone Against High Glucose-Induced Oxidative Stress

Diabetes exacerbates tendinopathy through oxidative stress and ROS production, often via NADPH oxidase (NOX). Mukohara et al. examined DHEA's antioxidant effects on rat tenocytes in low and high glucose conditions and diabetic rat tendons. By analyzing expressions of NOX, IL-6, MMP-2, TIMP-2, and collagen, both in vitro and in vivo, it aims to assess DHEA's effectiveness in reducing oxidative stress and improving tendon matrix turnover.

The WST assay showed rat tenocytes viability improved with 1, 10, and 20 μM DHEA, with 10 μM being the most effective, while 20 and 50 μM reduced viability in a dose-dependent manner (Fig. 1). At 48 hours, NOX1 and IL-6 mRNA levels were higher in the high glucose (HG) DHEA- group than in the low glucose (LG) DHEA- group, but lower in the HG DHEA+ group compared to the HG DHEA- group, with no change in NOX4 mRNA across groups (Fig. 2). ROS-positive cells were stained green, indicating greater ROS in the HG DHEA- group than the LG DHEA- group. ROS was lower in the HG DHEA+ group compared to the HG DHEA- group, with no difference between LG groups (Fig. 3A and B).

Fig. 1. Cell proliferation (Mukohara S, Mifune Y, et al., 2021).

Fig. 2. Quantitative real-time PCR analysis (Mukohara S, Mifune Y, et al., 2021).

Fig. 3. ROS accumulation (Mukohara S, Mifune Y, et al., 2021).

Comparison of Tenocytes Proliferation, Migration and Gene Expression in Five Animal Species

Tendinopathy, a prevalent musculoskeletal disorder, involves inflammation and impaired healing, costing billions annually. Animal models are essential for studying tendinopathy as human tissue is limited to severe cases. However, species differences affect inflammation responses and pathophysiology. Oreff et al. evaluated cellular and molecular inflammation features in tenocytes from humans and model animals (mouse, rat, sheep, and horse) to guide the selection of suitable models for tendon research.

Proliferation, migration, and gene expression of tenocytes from five species were compared under healthy and inflammatory conditions. Under healthy conditions (Fig. 4), horse tenocytes had the highest proliferation rates, while mouse tenocytes the lowest. Human tenocytes showed low proliferation and couldn't double in 48 hours, with sheep and rat in between. Figure 4 demonstrates significant slope differences among species but low variance within species, with model species significantly differing from humans. Under constant inflammation (10 ng/ml IL1β and TNFα), sheep tenocyte proliferation dropped to human levels, significantly altering their slope difference from the healthy state. Other slope differences under varying inflammatory conditions were not significant.

Fig. 4. The proliferation capacity (A–C) of tenocytes from 5 different mammalian species (mouse, rat, sheep, horse, and human) under healthy (Ctr/A), transient (TI/B) and constant (CI/C) inflammatory condition is illustrated as fold increase over the course of 2 days (Oreff G L, Fenu M, et al., 2021).