代谢型谷氨酸受体1和5激动剂改善阿霉素诱导的小鼠肾损伤

Metabotropic glutamate receptor 1/5 agonist improves doxorubicin-induced renal injury in mice

目的研究选择性代谢型谷氨酸受体1和5(mGluR1/5)激动剂3,5-二羟基苯甘氨酸(DHPG)对阿霉素(ADR)肾病小鼠模型的作用。方法 18只6周龄BALB/c小鼠随机分为对照组、ADR组(经尾静脉注射阿霉素建立阿霉素肾病小鼠模型)和ADR+DHPG组(建模前预先注射DHPG),每组6只。应用酶联免疫吸附试验(ELISA)方法检测小鼠24 h尿白蛋白水平,透射电子显微镜观察足细胞足突形态和宽度;免疫荧光染色激光共聚焦显微镜观察足细胞标志蛋白nephrin和损伤标志蛋白desmin的表达,免疫组织化学法检测肾小球WT-1表达;TUNEL染色检测足细胞凋亡情况。结果在对照组、ADR组和ADR+DHPG组24 h尿白蛋白分别为(1.67±0.22)、(22.55±2.34)和(8.23±2.74)mg,组间比较差异有统计学意义(P<0.01)。与ADR组比较,ADR+DHPG组小鼠足细胞的足突宽度缩短,desmin表达减少,而nephrin表达增加。肾小球中WT-1阳性细胞数与凋亡细胞数呈显著负相关(R2=0.8 482,P<0.05);ADR+DHPG组足细胞凋亡数显著少于ADR组(P<0.01)。结论选择性mGluR1/5激动剂DHPG可抑制ADR诱导的足细胞足突融合、nephrin表达减少和细胞凋亡,减少阿霉素肾病小鼠的白蛋白尿。

Objective To investigate the effects of selective agonist for metabotropic glutamate receptors 1 and 5（mGluR1/5）,（S）-3,5-dihydroxyphenylglycine（DHPG）,on the doxorubicin（ADR）-induced nephrosis in mice.Methods Eighteen 6-week-old male BALB/c mice were randomly divided into control group,ADR group（nephrosis model established by intravenous injection of ADR） and ADR＋DHPG group（pretreatment with DHPG injection before model establishment）,with 6 mice in each group.Twenty-four-hour urinary albumine levels were measured by enzyme-linked immunosorbent assay（ELISA）,and the foot processes effacement and the width of foot processes were determined with electron microscopy.Laser confocal microscope with immunofluorescence staining was employed to detect the expression of nephrin and desmin,and the expression of WT-1 in glomerulus was determined by immunohistochemistry.Besides,the apoptosis of podocytes was detected by TUNEL staining.Results Twenty-four-hour urinary albumine levels were（1.67±0.22） mg,（22.55±2.34） mg and（8.23±2.74） mg in control group,ADR group,and ADR＋DHPG group respectively,and there were significant differences among groups（P0.01）.Compared with ADR group,the width of foot processes in ADR＋DHPG was shorter,the expression of desmin was lower,and the expression of nephrin was higher.The number of WT-1 positive cells was negatively related to the number of apoptotic cells in glomerulus（R2=0.8 482,P0.05）,and the number of apoptotic podocytes in ADR＋DHPG group was significantly smaller than that in ADR group（P0.01）.ConclusionSelective mGluR 1/5 agonist DHPG may inhibit ADR-induced foot processes fusion of podocytes and decreased expression of nephrin,reduce cell apoptosis,and attenuate urinary albumine in ADR-induced nephrosis in mice.