The effect of quercetin on bone healing in an experimental rat model

Abstract

Objectives: This study aims to evaluate the effect of quercetin on fracture healing in an open fracture model in rats.

Materials and methods: A total of 80 Wistar-Albino male rats were used in this study. The rats were divided into 10 groups. Daily oral treatment of 100 mg/kg of quercetin dissolved in corn oil were given to four groups, whereas the other four group of control rats were treated with corn oil only. Histopathological and radiological examinations of fracture healing were performed at the end of Weeks 2 and 4 in these rats, while biomechanical and biochemical examinations were performed at the end of Weeks 4 and 6, since harder callus was required. Among the rats in the last two group that were not subjected to the open fracture model, one group was given only quercetin for three weeks and the other for six weeks, and the biochemical markers in the blood were compared between these two groups. Computed tomography images were taken for radiological evaluation. The modified Lane and Sandhu scoring system was used for histological evaluation. The 3-point bending test was performed for biomechanical evaluation. For biochemical evaluation, plasma alkaline phosphatase (ALP), acid phosphatase (AP), total antioxidant status (TAS) and total oxidant status (TOS) levels were measured.

Results: Radiologically, there was no significant difference between the early-stage results of quercetin and control groups (p=0.247), while quercetin caused a significant increase in callus tissue in terms of latestage results (p=0.012). Histopathologically, there was no significant difference in the early stage (p=0.584); however, in the late stage, a borderline significant increase was observed in the quercetin group compared to the control group (p=0.091). Biomechanical analysis showed that quercetin significantly increased the fracture strength in the healing bone both in the early period (p=0.036) and in the late period (p=0.027). Among biochemical markers, TOS and AP were found to be significantly decreased in the quercetin group. In the non-operated and quercetin given groups, TAS levels was significantly higher (p=0.001) and AP levels were borderline significantly lower at the end of Week 6 (p=0.063).

Conclusion: Quercetin did not have a significant effect on bone healing in the early period, but significantly promoted bone healing in the late period in rats. We recommend the use of quercetin, a strong antioxidant, in cases with high oxidative stress and conditions such as diabetes, smoking, and malnutrition which may inhibit fracture union, although further clinical studies are needed to confirm these findings.

Figure 1. Steps taken while creating an open fracture model.

Figure 2. Measurement of micro-computed tomography longitudinal sections of newly formed callus tissue in the femur after sacrification.

Figure 3. (a) Fibrous union findings at the control group fracture site in the second week (H&E, x100). Connective tissue areas and lymphocytic cell infiltration are seen between bone trabeculae. (b) Findings of osteochondral union at the quercetin group fracture site in the second week (H&E, x100). Enchondral ossification areas consisting of cartilage structures and woven type immature bone tissue are seen. (c) At the fourth week, bony union findings at the fracture site of the control group (H&E, x100). Among the bone trabeculae, ossification areas formed in woven type immature bone tissue are seen. (d) At the fourth week, signs of osteochondral union at the quercetin group fracture site (H&E, x100). Between the bone trabeculae, enchondral ossification areas consisting of woven type immature bone tissue and cartilage areas are seen.

Figure 4. Biomechanical evaluation, refraction of femur specimens by 3-point bending test.

Figure 5. (a) Low radiodensity bone/High radiodensity bone ratio (LOrb/HIrb). (b) Histoscore according to the histological scale of the modified Lane and Sandhu criteria. (c) Refraction with the 3-point bending test (Newton).