衰老和缺锌大鼠海马生长抑素含量及其阳性神经元的变化

Changes of the hippocampal somatostatin contents and neurons in aging and zinc deficiency rats

目的探讨海马结构内生长抑素（ＳＳ）含量及其阳性神经元的增龄变化，并分析这种变化与衰老过程中锌水平降低的关系。方法选用Ｗｉｓｔａｒ雄性大鼠４２只，分为缺锌组（７月龄）、老年组（２４月龄）和对照组（７月龄），每组各１４只。老年组和对照组均普食喂养，缺锌组以含１０ｍｇ／ｋｇ双硫腙的普食喂养。２周后，采用放免分析和原子吸收法，测定每组各８只大鼠海马和血浆ＳＳ含量及血浆锌含量；采用免疫组化ＡＢＣ法结合图像分析，观察每组各６只大鼠海马ＳＳ神经数目、灰度值和截面积。结果缺锌组血浆锌、ＳＳ含量和海马ＳＳ含量分别是１０．９±０．７μｍｏｌ／Ｌ、４２７±７２ｎｇ／Ｌ和１４３±２２ｐｇ／１００ｍｇ，老年组分别是１３．４±１．５μｍｏｌ／Ｌ、４１４±２１ｎｇ／Ｌ和１５７±２８ｐｇ／１００ｍｇ，２组均较对照组的血浆锌（１６．３±１．６μｍｏｌ／Ｌ）、ＳＳ含量（６１１±３６ｎｇ／Ｌ）和海马ＳＳ含量（２０４±６７ｐｇ／１００ｍｇ）明显降低（均为Ｐ＜０．０５）；缺锌和老年组海马ＳＳ阳性神经元的数目分别是３０±６和３６±６个／切片，其灰度值分别是０．２７±０．０６和０．２７±０．０２度，均较对照组的神经元数目（５０±５个／切片）和灰度值（０?

Objective To study the effects of zinc deficiency on the hippocampal somatostatin(SS) neurons in aging process, from observations on the changes of SS levels and SS neurons in the hippocampus of the aging and zinc deficiency rats. Methods Fortytwo male Wistar rats were divided into three groups of 14 each: zinc deficiency group (7 months) on general diet containing dithizone (10 mg/kg), aged group (24 months) and control group (7 months) on general diet. After 2 weeks the plasma and hippocampus SS contents and plasma zinc content of 8 rats from each group were measured with radioimmunoassay and atomic absorption methods. The hippocampal SS neurons of 6 rats from each group were observed with ABC immunochemical technique and the image qantitative analysis. Results In the zinc deficiency and aged group plasma zinc(109±07 vs 134±15 μmol/L), plasma SS (427±72 vs 414±21ng/L), hippocampal SS (143±22 vs 157±28 pg/100mg) were all lower than those in the control group (plasma zinc 163±16μmol/L and SS 611±36ng/L, hippocampal SS 204±67pg/100mg).In the zinc deficiency and aged groups hippocampal SS neurons (30±6 vs 36±6 No./section) and grey values (027±006 vs 027±002 degree) were less or lower than in control group (hippocampal SS neurons 50±5 No./section and grey value 045±003 degree). Conclusions With aging, the SS contents and SS neurons in hippocampus decreased obviously, which is concerned with the lower zinc level in aging process.