• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.811-817
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• 2019

Radiation-therapy causes the adverse radiation effect. It is called osteoradionecrosis. A protein-therapy is carried out in order to cure osteoradionecrosis. The typical method of the protein-therapy is using BMP-2. Considering to bone damage, it is more important that maintains enough to circumstance regeneration for osteoblast differentiation on damage site of bone. Thus, this study is on a tissue regeneration to cure radiation critical damage. I observed that the formation of new regeneration bone by injection of collagen sheet BMP-2 on irradiated mouse. Consequently, I examined new bone formation with collagen sheet BMP-2 on irradiated mouse after 8weeks. Therefore I suggested that using collagen sheet BMP-2 which can be good for new bone regeneration effect on radiation side effect area.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.202-210
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• 2015

The low dose radiation is done for a long period, thus researchers have to know the exact dose distribution for the irradiated mouse. This research has been conducted in order to find out methods in transmitting an exact dose to mouse in a mouse irradiation experiment carried out using $^{137}Cs$ irradiation equipment installed in the DIRAMS (Dongnam Institution of Radiological & Medical Sciences) research center. We developed a single mouse housing cage and shelf with adjustable geometric factors such as distance and angle from collimator. The measurement of irradiated dose showed a maximal 42% difference of absorbed dose from the desired dose in the conventional irradiation system, whereas only 6% difference of the absorbed dose was measured in the self-developed mouse apartment system. In addition, multi mice housing showed much difference of the absorbed dose in between head and body, compared to single mouse housing in the conventional irradiation system. This research may allow further research about biological effect assessment for the low dose irradiation using the self-developed mouse apartment to provide more exact doses which it tries to transmit, and to have more reliability for the biological analysis results.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.34.1-34.8
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• 2018

Background: Radiation therapy is widely employed in the treatment of head and neck cancer. Adverse effects of therapeutic irradiation include delayed bone healing after dental extraction or impaired bone regeneration at the irradiated bony defect. Development of a reliable experimental model may be beneficial to study tissue regeneration in the irradiated field. The current study aimed to develop a relevant animal model of post-radiation cranial bone defect. Methods: A lead shielding block was designed for selective external irradiation of the mouse calvaria. Critical-size calvarial defect was created 2 weeks after the irradiation. The defect was filled with a collagen scaffold, with or without incorporation of bone morphogenetic protein 2 (BMP-2) (1 ㎍/ml). The non-irradiated mice treated with or without BMP-2-included scaffold served as control. Four weeks after the surgery, the specimens were harvested and the degree of bone formation was evaluated by histological and radiographical examinations. Results: BMP-2-treated scaffold yielded significant bone regeneration in the mice calvarial defects. However, a single fraction of external irradiation was observed to eliminate the bone regeneration capacity of the BMP-2-incorporated scaffold without influencing the survival of the animals. Conclusion: The current study established an efficient model for post-radiation cranial bone regeneration and can be applied for evaluating the robust bone formation system using various chemokines or agents in unfavorable, demanding radiation-related bone defect models.

• Biomedical Science Letters
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• v.15 no.1
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• pp.87-91
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• 2009

In photodynamic therapy (PDT), oxygen plays important role. Because of singlet oxygen which is produced by activated photosensitizer after laser irradiation of specific wavelength. The aim of this study is to find how oxygen concentration affects anticancer effect in PDT. Groups were divided into PDT with oxygen applied group and only PDT applied group. PDT with oxygen applied group supplied oxygen for 15 minute before laser irradiation. In vitro, CT-26 cell was incubated with various concentration of photofrin $(50.0{\sim}0.05{\mu}g/ml)$ and was irradiated with 632nm diode laser 6hr after application of photofrin. The cell viability of two groups was assessed by MTT assay. In vivo, CT-26 cell line was transplanted into the subcutaneous tissue of BALB/c mouse. The anticancer effect of two groups was measured by tumor volume change. In vitro study, the cell viability was significantly decreased at $1.56{\sim}3.13{\mu}g/ml$ in PDT with oxygen applied group. In vivo study, the PDT with oxygen applied group significantly higher reduction rate of tumor volume 7 days after PDT compared to PDT only group. The high oxygen concentration might enhance the anticancer effect of the photodynamic therapy.

• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.539-545
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• 2021

Radiation therapy is accompanied by adverse radiation effective. In particular, it is accompanied by disorders of the vascular system. Therefore, oxygen and nutrient deficiency occurs in the regeneration area. Eventually, osteoradionecrosis is formed in this cellular environment. According to a precedent study, bone morphogenetic protein-2 is used to overcome osteoradionecrosis. The purpose of this study was to investigate the regeneration ability of osteoradionecrosis by treating bone-forming protein-2 on a fibrinogen scaffold which is a biomaterial that is frequently used for bone regeneration after irradiation of the rat head. In addition, the purpose of this study was to verify the bone regeneration effect from the eight weeks. According to the experimental results, in the calvarial defected model of the irradiated mouse, making bone-formation was obtained after 8 weeks rather than bone-formation period in the early 4 weeks. moreover, it was found that the regenerated bone formation of the fibrinogen scaffold is formed from the inside of the bone of the defect area.

• Radiation Oncology Journal
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• v.26 no.4
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• pp.257-262
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• 2008

Purpose: Oral mucositis induced by radiotherapy to the head and neck area, is a common acute complication and is considered as the most severe symptom for cancer patients in the early stages of treatment. This study was proposed to establish the oral mucositis mouse model induced by a single dose of radiation for the facility of testing therapeutic candidates which can be used for the oral mucositis treatments. Materials and Methods: Fifty-five BALB/c mice were divided into four groups: control, 16 Gy, 18 Gy, and 20 Gy. Oral mucositis was induced by a single dose of radiation to the head and neck using 6 MV x-Ray from linear accelerator. After irradiation, body weight and physical abnormalities were checked daily. Tongue tissues from all groups were taken on days 1, 2, 3, 5, 7, 9, and 14, respectively and H&E staining was conducted to examine morphological changes. Results: Body weight dramatically decreased after day 5 in all irradiated mice. In the 16 Gy treatment group, body weight was recovered on day 14. The histology data showed that the thickness of the epithelial cell layer was decreased by the accumulated time after radiation treatment, up to day 9. Severe ulceration was revealed on day 9. Conclusion: A single dose of 16 Gy is sufficient dose to induce oral mucositis in Balb/C mice. Significant changes were observed in the Balb/C mice on days 7 and 9 after radiation. It is suggested that this mouse model might be a useful standard tool for studying oral mucositis induced by radiation.