番茄红素对慢性低氧小鼠骨密度和RANKL/OPG的影响

Effects of lycopene on bone mineral density and RANKL/OPG in chronic hypoxia modal mice

目的:探讨番茄红素对慢性低氧(CH)小鼠骨密度(BMD)和核因子-kβ受体活化因子配体(RANKL)/骨保护蛋白(OPG)的影响。方法:选用8周龄C57BL/6雄性小鼠24只,随机分为对照组(C组,n=8)、CH组(n=8)和番茄红素组(LCP组,n=8)。C组在正常环境下饲养,CH组和LCP组低氧暴露时间为每日8h,每周6d,连续8周。于实验末取血1.5m L,ELISA法测量血清抗酒石酸酸性磷酸5b(TRACP-5b)、骨钙素(OC);同时检测骨组织丙二醛(MDA)含量,超氧化物歧化酶(SOD)活性;用骨密度仪检测股骨BMD;HE染色光镜观察骨组织形态学改变;用免疫组织化学技术和实时荧光定量PCR(RT-q PCR)技术检测骨组织骨保护素(OPG)和核因子-κB受体活化因子配体(RANKL)蛋白及m RNA的表达。结果:1CH组股骨干骺端骨小梁分布稀疏,变细及断裂;骨组织SOD活性、BMD和血清OC明显低于C组;而骨组织MDA、RANKL水平、RANKL mRNA/OPG mRNA以及血清TRACP-5b显著高于C组(P<0.01)。2LCP能部分改善CH小鼠骨组织形态学;LCP组骨组织MDA水平、RANKL表达、RANKL mRNA/OPG mRNA和血清TRACP-5b水平低于CH组;而骨组织SOD活性、血清OC水平和BMD高于CH组(P<0.05或0.01)。结论:番茄红素能降低CH小鼠骨组织氧化应激水平,下调RANKL/OPG,减少骨吸收,提高BMD。

Objective： To investigate the effects of lycopene on bone mineral density（BMD） and RANKL/OPG in chronic hypoxia（CH） modal mice. Methods： Twenty-four C57BL/6 male mice aged 8 weeks were randomly divided into three groups： Control group（C group, n=8） and CH group（CH group, n=8） and lycopene group（LCP group, n=8）. Mice in CH and LCP were exposed in hypoxic environment, 8 h/day, 6 d/week while the C group lived in normal environment. At the end of 8 weeks, the serum levels of OC and TRACP-5b were measured by ELISA. The content of malondiadehyde（MDA） and the activity of superoxide dismutase（SOD） in shinbone were analyzed using hydroxylamine assay and TBA colorimetry. The BMD of right femurs were detected by Hologic QDR-4500 bone densitometer. Histomorphology of bone tissue was observed with H.E stainin under light microscopy. The expressions of OPG and RANKL in bone tissue were detected with immunohistochemical technique and RT-q PCR respectively. Results： Firstly, Histologically, the volume of bones trabecular were decreased and the bones trabecular distribution were sparse, thinner and fracture in bone marrow in CH group. In comparison with the C group mice, BMD and serum OC level and the activities of SOD in bone（P〈0.01） were decreased significantly in CH group mice, while the serum TRACP-5b level, MDA level in bone, the expression of RANKL protein and RANKL m RNA in bone and RANKL m RNA/OPG m RNA（P〈0.01） were increased significantly. Secondly, LCP could partially improve the histomorphometric parameters in mice with CH. The serum TRACP-5b level, MDA level in bone, the expression of RANKL protein and m RNA in bone and RANKL mRNA/OPG mRNA in LCP group mice were lower significantly than the levels in HC group mice, while BMD and serum OC level and the activities of SOD in bone were higher（P〈0.01 or P〈0.05）. Conclusion： Lycopene can reduce oxidative stress, regulate RANKL mRNA/OPG mRNA, decrease bone resorption and improve BMD in CH mice.