RESUMO
OBJECTIVES: This study aims to evaluate the effect of diabetes mellitus (DM) on intramuscular fatty degeneration after a full-thickness supraspinatus (SS) tendon tear in rats. MATERIALS AND METHODS: The study included 24 adult male Wistar Albino rats (age, 18 to 24 weeks; weighing, 320-380 g) randomized into a sham group (n=6), control group (n=6) and experimental group (n=12). Rats with fasting blood glucose levels ≥250 mg/dL at each measurement after an injection of streptozotocin were accepted to have DM. On the seventh day of the study, the SS muscles of the rats in the experimental and control groups were cut from the insertion. All animals were performed euthanasia four weeks after the surgical procedure and SS muscles were excised completely. Fatty degeneration in the SS muscle was assessed histologically and immunohistochemically with oil red O and peroxisome proliferator-activated receptor gamma (PPAR-γ) staining using histological score (H-score) and quantitative methods. RESULTS: More intense oil red O and PPAR-γ staining was observed in all regions of the SS muscles of the experimental group compared to control and sham groups (p<0.05). CONCLUSION: The results of this study showed that DM accelerates intramuscular fatty degeneration after SS tendon tears. Fatty degeneration should be monitored closely in diabetic patients with rotator cuff tear who were selected for conservative treatment and early surgical treatment should be considered as an option.