p53半剂量缺失纠正1,25(OH)_(2)D_(3)缺乏小鼠的骨质疏松

p53 heterozygote attenuates osteoporosis phenotype of 1,25(OH)_(2)D_(3) deficient mice

目的:探索p53半剂量缺失杂合子小鼠能否通过增强抗氧化能力纠正活性维生素D(1,25(OH)_(2)D_(3))缺乏引起的骨质疏松。方法:取10周龄高钙高磷饮食喂养的同窝野生型(wild type,WT)小鼠、p53半剂量缺失杂合子(p53^(+/-))小鼠、1α-羟化酶基因敲除[1α(OH)ase^(-/-)]小鼠及p53半剂量缺失的1α羟化酶基因敲除[1α(OH)ase^(-/-)p53^(+/-)]小鼠的长骨,利用X线、micro-CT、组织病理学和分子生物学等方法,比较各组小鼠血清学、长骨骨矿化、骨形成、骨吸收以及氧化应激等表达变化。结果:与WT小鼠相比,p53^(+/-)小鼠血清钙、磷、甲状旁腺素(parathyroid hormone,PTH)和1,25(OH)_(2)D_(3)水平差异无统计学意义,骨密度、总胶原(total collagen,T-col)阳性面积、成骨细胞数量、碱性磷酸酶(alkaline phosphatase,ALP)和Ⅰ型胶原(collagen type Ⅰ,Col-Ⅰ)阳性面积均有所增加,活性氧水平降低,抗氧化酶SOD1表达增加。与1α(OH)ase^(-/-)小鼠相比,1α(OH)ase^(-/-)p53^(+/-)小鼠血清钙、磷和PTH差异无统计学意义,血清中检测不到1,25(OH)_(2)D_(3),骨密度、T-col阳性面积、成骨细胞数量、ALP和Col-Ⅰ阳性面积均明显增加,破骨细胞数量减少,活性氧水平降低,抗氧化酶SOD1表达增加。结论:p53半剂量缺失可通过增强抗氧化能力纠正1,25(OH)_(2)D_(3)缺乏小鼠的骨质疏松。

Objective:To explore whether p53 heterozygote attenuates osteoporosis phenotype of 1,25(OH)_(2)D_(3) deficient mice by enhancing the antioxidant capacity.Methods:The long bones of 10-week-old wild type(WT)mice,p53 heterozygote(p53^(+/-))mice,1α-hydroxylase knockout[1α(OH)ase^(-/-)]mice,and 1α(OH)ase^(-/-)p53^(+/-)mice,fed on a high-calcium and high-phosphorus diet,were analyzed and compared using X-ray,micro-CT,histopathological and molecular biology methods to observe and compare changes in serum levels,bone mineralization,bone formation,bone absorption,and oxidative stress expression.Results:Compared with WT mice,p53^(+/-)mice showed no significant differences in serum calcium,phosphorus,parathyroid hormone(PTH),and 1,25(OH)_(2)D_(3) levels,but had the increased bone density,total collagen(T-col)positive area,osteoblast number,alkaline phosphatase(ALP),and type Ⅰ collagen(col-Ⅰ)positive area,along with the decreased levels of reactive oxygen species and the increased expression of the antioxidant enzyme SOD1.Compared with 1α(OH)ase^(-/-)mice,1α(OH)ase^(-/-)p53^(+/-)mice showed no significant differences in serum calcium,phosphorus,and PTH levels,with undetectable levels of 1,25(OH)_(2)D_(3) in the serum,but showed significantly increased bone density,T-col positive area,osteoblast number,ALP and Col-Ⅰ positive area,decreased osteoclast number and reactive oxygen species levels,and increased expression of SOD1.Conclusion:Half-dose deletion of p53 can attenuate osteoporosis phenotype of 1,25(OH)_(2)D_(3) deficient enhancing the antioxidant capacity.