Oxygen-free radicals impair fracture healing in rats

Göktürk, Erol; Turgut, Akin; Bayçu, Cengiz; Günal, I; Seber, Sinan; Gulbas, Zafar

doi:10.3109/17453679508995590

Cited by 84 publications

(83 citation statements)

References 12 publications

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“…As in some other clinical trials (Prasad et al 2003), the levels of NO were found to be high especially on the postfracture 7th and 14th days in the present study. These fi ndings show that NO production increases in an signifi cant amount in the 2nd and 3rd weeks of fracture, when the most intense oxidative stress occurs (Gokturk et al 1995;Prasad et al 2003;Petrovich et al 2004;Yeler et al 2005;Cetinus et al 2005). The extreme production of NO may cause peroxynitrite-related tissue damage and a consequent disturbance of fracture healing, especially at the 2nd and 3rd weeks following the fracture.…”

Section: Discussionmentioning

confidence: 99%

“…Ischemia-reperfusion mechanisms may cause an oxidative stress injury in a fractured extremity. Some studies indicate that oxidative stress occurred especially on the 7th and 14th days after the fracture (Gokturk et al 1995;Prasad et al 2003;Petrovich et al 2004;Yeler et al 2005;Cetinus et al 2005). The common idea in those studies is as follows: the fi rst few days of fracture healing is the ischemia period and no oxidative stress injury occurs during this time.…”

Section: Discussionmentioning

confidence: 99%

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Time-Dependent Changes in Serum Nitric Oxide Levels after Long Bone Fracture

Keskin

Kızıltunç

2007

Tohoku J. Exp. Med.

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Nitric oxide (NO) is a free radical of physiological signifi cance. The changes in the production of NO during the fracture healing process are not well known. This clinical prospective study was planned to determine these changes in patients with fractured long bone(s), who underwent surgery in the 3rd week after fracture. The patients were divided into two groups: 20 patients with an isolated femoral fracture and 20 patients with multiple fractures, including a femoral fracture. Venous blood was drawn from the healthy volunteers (n = 20) once, and from the patients seven times during 21 days after fracture. NO level was measured as nitrite in each serum sample. The serum NO levels at all measurements of the patients were signifi cantly higher than those of the control subjects. The timedependent changes in the NO levels were similar in both patient groups. The serum NO levels were highest in the fi rst 6 hrs, and then decreased to the lowest level on the 3rd day. Subsequently, there was an increasing trend on the 5th, 7th and 14th days. At all times of the measurements, the NO levels were higher in patients with multiple fractures than in those with the femoral fracture, with the signifi cant difference observed at the 6 hrs and on the 7th day. The NO levels were decreased on the 21st day after surgery. The present study suggests that NO production may be increased in considerable amounts during the fi rst 2 weeks of fracture healing, particularly in the fi rst 6 hrs.human; bone; fracture; blood; nitric oxide © 2007 Tohoku University Medical PressNitric oxide (NO) is a physiological free radical, synthesized from the amino acid L-arginine by the 3 NO synthase (NOS) isoforms; neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS). It functions in vascular regulation, host immune defense, neurotransmission, and other systems. While some diseases, like vascular dysfunctions, impair NO production, some diseases, like septic schock, cerebral infarction, diabetes mellitus and neurodegenerative disorders, augment NO production (Mori and Gotoh 2004). It is not clear how NO affects bone cells. Some studies show that NO has a biphasic effect on bone cell activity. It has been stated that moderate concentrations of NO produced by eNOS in the bone is necessary for normal osteoblast growth and fracture healing (Ralston 1997;Corbett et al. 1999). However, it was suggested that high concentrations of NO produced by cytokine-induced iNOS activity may inhibit the

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Time-Dependent Changes in Serum Nitric Oxide Levels after Long Bone Fracture

Keskin

Kızıltunç

2007

Tohoku J. Exp. Med.

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“…It has been reported 30 that negative effects of free oxygen radicals seem to be more prominent during the early phases of the healing period, since antioxidants have been found to be most effective during this phase. In our study, the systemic application of propolis extract after the expansion period was similar to the methods of studies 8 that surveyed bone healing after expansion.…”

Section: Discussionmentioning

confidence: 99%

Systemic propolis stimulates new bone formation at the expanded suture

Altan

Kara

Nalçacı

et al. 2012

The Angle Orthodontist

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Objective: To investigate the effects of systemically given propolis on the expanded premaxillary suture in a rat study model. Materials and Methods: The 24 rats were randomly divided into three groups-only expansion (OE), expansion plus propolis (PRO), and nonexpansion (control) groups. After the 5-day expansion period was completed, the OE and PRO groups underwent 12 days of mechanical retention. At the end of this period, the animals were euthanatized and their pre-maxillae were dissected and fixed. Histomorphometric examination was performed to determine the number of osteoclasts, osteoblasts, and capillaries as well as the intensity of inflammatory cells and amount of new bone formation. Results: Statistical analysis showed that the intensities of inflammatory cells, number of osteoblasts, and amount of new bone formation were greater in the PRO group than in the other groups. The PRO group also had more osteoclasts and new capillaries. Conclusion: Systemic use of propolis may hasten new bone formation at the expanded suture in rats. (Angle Orthod. 2013;83:286-291.)

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“…An exaggerated activation of neutrophils using oxygen free radicals is associated with defective healing of bone fracture [106], while an induced neutropenia in animal models of bone defects shows an enhanced osteogenic repair [107]. Likewise, excessive stimulation of macrophages with lipopolysaccharide can decrease their production of BMP-2 causing a delayed bone healing [108].…”

Section: The Uncontrolled Immune Cell Response and Defective Bone Heamentioning

confidence: 99%