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电离辐射直接作用于机体,可通过能量沉积或产生自由基造成DNA结构和功能的损伤,从而导致急、慢性放射病甚至致癌等一系列的生物学后果。DNA损伤和修复的程度决定了其生物学的最终结局。近年来,国内外研究表明角质细胞生长因子(keratinocyte growth factor,KGF)可有效防治辐射损伤,且作用迅速、高效,有望成为新的辐射防护细胞因子[1-2]。本实验以137Cs γ射线照射小鼠建立辐射损伤模型,运用单细胞凝胶电泳(single cell gel electrophoresis,SCGE)和微核实验,评价KGF对受照小鼠的遗传保护作用,为研究KGF作为辐射损伤防治药物提供理论依据。
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各实验组小鼠彗星尾部DNA百分含量、尾长、尾矩、Olive尾矩分别见图 1和表 1。结果显示,小鼠接受7.2 Gy γ射线全身一次性照射后,照射对照组各项指标与空白对照组相比均明显升高,差异有统计学意义(t=6.226、9.520、3.924和5.369,P均 < 0.01),提示造模成功。与照射对照组相比,KGF低剂量组各项指标差异均无统计学意义,中剂量组各项指标差异均有统计学意义(t=2.385、3.188、2.733和2.892,P分别为 < 0.05、 < 0.01、 < 0.01和 < 0.01),高剂量组的差异更加明显(t=3.189、6.987、3.648和3.097,P均 < 0.01)。以上结果提示KGF可促进小鼠淋巴细胞DNA损伤的修复,且修复能力与KGF的给药剂量存在一定相关性。
组别 只数 尾部DNA百分含量(%) 尾长(μm) 尾矩 Olive尾矩 空白对照组 8 1.22±2.76 7.24±7.09 0.31±1.04 0.49±0.90 照射对照组 8 4.72±5.20 19.73±13.90 1.83±3.92 1.93±2.57 KGF低剂量组 8 5.21±4.31 20.22±14.06 1.62±3.06 1.76±2.00 KGF中剂量组 8 3.65±3.15 16.35±8.96 0.85±1.10 1.31±1.00 KGF高剂量组 8 3.41±1.37 13.04±4.08 0.32±0.26 0.59±0.34 F值 17.731 35.950 8.194 10.814 P值 <0.01 <0.01 <0.01 <0.01 注:表中,KGF:角质细胞生长因子。 表 1 各组小鼠彗星尾部DNA百分含量、尾长、尾矩、Olive尾矩的比较
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各实验组小鼠微核率、PCE/NCE值结果见表 2。结果显示,小鼠接受7.2 Gy γ射线全身一次性照射后,与空白对照组相比,照射对照组微核率显著升高,PCE/NCE值显著降低,差异均有统计学意义(t=5.336和4.511,P均 < 0.01),提示造模成功。与照射对照组相比,KGF低剂量组微核率显著降低(t=3.805,P < 0.01),PCE/NCE值明显升高(t=2.181,P < 0.05);中剂量组和高剂量组微核率显著降低(t=4.391和4.935,P均 < 0.01),PCE/NCE值显著升高(t=3.914和7.312,P均 < 0.01)。以上结果提示KGF可减少辐射引起的染色体异常,且可能减轻辐射引起的骨髓抑制。
组别 只数 微核率(‰) PCE/NCE值 空白对照组 8 3.00±1.00 2.0±0.7 照射对照组 8 77.60±13.81 0.6±0.2 KGF低剂量组 8 26.67±12.40 1.4±0.8 KGF中剂量组 8 18.83±8.30 1.5±0.3 KGF高剂量组 8 9.00±4.94 2.7±0.5 F值 9.056 14.118 P值 <0.01 <0.01 注:表中,KGF:角质细胞生长因子;PCE:嗜多染红细胞;NCE:正染红细胞。 表 2 各组小鼠微核率、PCE/NCE值的比较
角质细胞生长因子对受照小鼠的遗传保护作用
Keratinocyte growth factor pretreatment prevents radiation-induced genetics damage in a mouse model
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摘要:
目的 应用单细胞凝胶电泳(SCGE)和微核实验探讨角质细胞生长因子(KGF)对受照小鼠的遗传保护作用。 方法 将40只C57BL/6J小鼠随机分为空白对照组、照射对照组、KGF低(1 mg/kg)、中(2 mg/kg)、高(4 mg/kg)剂量组5组。KGF的3个给药组于照射前给药,连续3 d分别给予腹腔注射1、2、4 mg/kg的KGF,1次/d。照射对照组腹腔注射磷酸盐缓冲液。给药后,空白对照组给予假照射,其他4组给予7.2 Gy 137Cs γ射线全身一次性照射。应用SCGE和微核实验检测5组小鼠的DNA损伤情况。 结果 与照射对照组相比,KGF低剂量组小鼠的DNA微核率显著降低,中、高剂量组的彗星尾矩、Olive尾矩和微核率均显著降低。 结论 KGF对受照小鼠有显著的遗传保护作用。 Abstract:Objective To study the protective effect of keratinocyte growth factor (KGF) in genetics damage induced by radiation using the methods of single cell gel electrophoresis (SCGE) and micronuclei assay. Methods The C57BL/6J mice were randomly divided into five groups:control group, radiation group and low, middle, high dose groups of KGF(1, 2, 4 mg/kg). Drugs were administrated by intraperitoneal injection. Then control group was given sham-irradiated, and other groups were given a whole body irradiation at the dose of 7.2 Gy with γ-rays. DNA damage of different groups were detected by SCGE and micronuclei assay. Results Compared with radiation group, pretreatment with KGF can significantly decrease the tail moment and micronucleus formation. Conclusion Pretreatment with KGF can effectively protect the radiation-induced genetics damage in mouse model. -
Key words:
- Fibroblast growth factor /
- Radiation injuries /
- Comet assay /
- Micronucleus tests
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表 1 各组小鼠彗星尾部DNA百分含量、尾长、尾矩、Olive尾矩的比较
组别 只数 尾部DNA百分含量(%) 尾长(μm) 尾矩 Olive尾矩 空白对照组 8 1.22±2.76 7.24±7.09 0.31±1.04 0.49±0.90 照射对照组 8 4.72±5.20 19.73±13.90 1.83±3.92 1.93±2.57 KGF低剂量组 8 5.21±4.31 20.22±14.06 1.62±3.06 1.76±2.00 KGF中剂量组 8 3.65±3.15 16.35±8.96 0.85±1.10 1.31±1.00 KGF高剂量组 8 3.41±1.37 13.04±4.08 0.32±0.26 0.59±0.34 F值 17.731 35.950 8.194 10.814 P值 <0.01 <0.01 <0.01 <0.01 注:表中,KGF:角质细胞生长因子。 表 2 各组小鼠微核率、PCE/NCE值的比较
组别 只数 微核率(‰) PCE/NCE值 空白对照组 8 3.00±1.00 2.0±0.7 照射对照组 8 77.60±13.81 0.6±0.2 KGF低剂量组 8 26.67±12.40 1.4±0.8 KGF中剂量组 8 18.83±8.30 1.5±0.3 KGF高剂量组 8 9.00±4.94 2.7±0.5 F值 9.056 14.118 P值 <0.01 <0.01 注:表中,KGF:角质细胞生长因子;PCE:嗜多染红细胞;NCE:正染红细胞。 -
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