The effects of zinc sulfate mineral supplementation on Achilles tendon healing in rats.

BACKGROUND: The Achilles tendon is the most commonly injured and ruptured tendon in the body and typically occurs during participation in sports or recreational activities in men between 30 and 50 years of age. Treatment options for Achilles tendon rupture include conservative and surgical approaches. Conservative treatment is associated with a higher risk of rerupture, while surgical treatment carries a risk of wound site complications. Generally, both methods result in a prolonged tendon healing time. Studies are ongoing to identify biomolecules that aid tendon repair. The main objective of our study is to investigate the effects of zinc sulfate (ZnSO4) mineral supplementation on Achilles tendon healing in rats. METHODS: Forty-eight female Sprague-Dawley rats were divided into four equal groups (C-15, C-30, ZnSO4-15, and ZnSO4-30) after standard Achilles tendon repair surgery. The ZnSO4-15 and ZnSO4-30 groups received an oral zinc sulfate monohydrate solution (50 mg/kg/day) for 15 and 30 days, respectively. The C-15 and C-30 groups were given 1 mL of distilled water per day orally during the experimental periods. Rats were sacrificed on the 15th and 30th day depending on their groups, and the healing of the operated tendons was evaluated using Movin and Bonar histopathologic scoring. For biomechanical analyses, the operated and intact Achilles tendons of all groups were removed, and tensile tests were performed to determine the tensile strength and toughness values for each tendon. RESULTS: Movin and Bonar scores were significantly lower in the ZnSO4-15 group than in the C-15 group and in the ZnSO4-30 group than in the C-30 group (p<0.05). Although we did not find the biomechanical results statistically significant, the intact tendons of the ZnSO4-15 group exhibited higher toughness than those of the C-15 group, and the tensile strength and toughness values of the operated and intact tendons of the ZnSO4-30 group were also higher than those of the C-30 group. CONCLUSION: Zinc sulfate monohydrate mineral supplementation had histopathologically positive effects on the proliferation and remodeling stages of Achilles tendon healing and may biomechanically benefit both operated and intact tendons.

The effects of hydroxychloroquine-induced oxidative stress on fracture healing in an experimental rat model.

OBJECTIVES: The purpose of this study was to investigate whether hydroxychloroquine (HCQ) sulfate causes oxidative stress (OS) and its effect on fracture healing in an experimental rat model. MATERIALS AND METHODS: In this experimental study, open diaphyseal femur fractures were induced in 24 eight-week-old male rats (mean weight: 225±25 g; range, 200 to 250 g) and then fixed with K-wire. The rats were divided into four groups: HCQ-2, control-2 (C-2), HCQ-4, and control-4 (C-4). During the study period, rats in the HCQ groups received an HCQ solution (160 mg/kg/day), whereas rats in the control groups received saline. The HCQ-2 and C-2 groups were sacrificed on the 14th day, and the HCQ-4 and C-4 groups were sacrificed on the 28th day. After sacrifice, malondialdehyde levels induced by OS were calculated for each rat, and fracture healing was evaluated radiographically, histomorphometrically, histopathologically, and immunohistochemically. RESULTS: Malondialdehyde levels were higher in the HCQ groups than in the control groups (p<0.05). Hydroxychloroquine caused OS in rats. The ratio of total callus diameter to femur bone diameter was lower in HCQ groups compared to control groups (p<0.05). No differences were observed when comparing radiological and histological healing results between the control and HCQ groups. Alkaline phosphatase levels were lower in the HCQ-4 group than the C-4 group at week four (p<0.05), although osteocalcin and osteopontin levels did not differ between groups (p>0.05). Oxidative stress had no adverse effects on histologic healing outcomes and osteoblast functions. Cathepsin K and tartrate-resistant acid phosphatase-5b levels were higher in the HCQ-4 group than in the C-4 group (p<0.05). While the number and function of osteoclasts increased due to OS in callus tissue, a decrease in the number of chondrocytes was observed. CONCLUSION: Hydroxychloroquine-induced OS increases the number and function of osteoclasts and decreases the number of hypertrophic chondrocytes and endochondral ossification but has no significant effect on mid-late osteoblast products and histological fracture healing scores.