大鼠组织一氧化氮含量变化及其调节在衰老过程中的作用

Changes of nitric oxide concentration in rats tissue and the role of modulating nitric oxide synthesis in aging

目的 揭示大鼠组织一氧化氮 ( NO)含量和一氧化氮合酶 ( NOS)活性变化与衰老的相关关系 ,并通过调节 NO合成 ,探讨 NO在衰老过程中的作用。 方法 对不同月龄大鼠采用铜离子活化镉还原法测定组织 NO含量 ,应用血红蛋白氧化法测定组织 NOS的活性 ,采用硫代巴比妥酸染色法测定组织丙二醛 ( MDA)含量。 结果 与青年组相比 ,老年组 ( 2 0～ 2 2月龄 )心脑肾组织 NO降低有显著性 ( P<0 .0 1 ) ,而中年组仅肾组织 NO含量降低有显著性 ( P<0 .0 5) ;老年组较中年组仅心脏组织 NO含量降低有显著性 ( P<0 .0 1 )。中年组心脑组织 NOS活性较青年组降低 ( P<0 .0 5) ;而老年组组织 NOS活性较中年组增高 ,仅脑组织 NOS增高有显著性 ( P<0 .0 5)。与老年对照组比较 ,β-雌二醇组心肝肾脑组织 NO含量明显增高 ( P<0 .0 1 ) ,而心脑肾组织 MDA下降有显著性 ( P<0 .0 1 ) ;L-硝基精氨酸甲酯组肝组织 NO降低有显著性 ( P<0 .0 5) ,而 MDA下降仅在脑组织有显著性 ( P<0 .0 5)。 结论 大鼠组织 NO含量与衰老之间存在一定的相关关系。

Objective To investigate the relation between changes of tissues nitric oxide (NO), nitric oxide synthase (NOS) activity and aging. To modulate NO synthesis by increasing or inhibiting NOS activity for demonstrating the role of NO in aging. Methods Rats tissue inorganic nitrate concentration was detected by Cu 2+ activated cadmium reduction method. Tissue NOS activity in heart, liver, brain and kidney was determined by oxyhemoglobin oxidation method. Tissue malonaldehyde(MDA) was determined by thiobarbituric acid test. Results Compared with the young group, NO significantly decreased in heart, brain and kidney in the aged group ( P <0 01),but only decreased significantly in kidney in the middle age group ( P <0 05). Compared with the middle age group, NO decreased significantly in heart in the aged group ( P <0 01). NOS activity in heart and brain was also lower in the middle age group than that in the young group ( P <0 05). NOS activity in heart and brain was higher in the aged group than that in the middle age group, but just in brain had significant difference between two groups ( P <0 05). Compared with the aged group as control, β estradiol induced NO significantly increased in heart, liver, kidney and brain ( P <0 01), but tissue MDA in heart, brain and kidney significantly decreased ( P <0 01). L nitroarginine methylester (L NAME) induced NO in liver decreased significantly ( P <0 05),but MDA only in the brain tissue decreased significantly ( P <0 05). Conclusions The study demonstrates relative relation between NO and aging.