大鼠肾小管上皮细胞透明质烷和CD44表达对草酸钙晶体黏附的影响

Influence of hyaluronan and CD44 expression in renal tubular epithelial cells on the adherence of calcium oxalate crystal

目的研究受损的肾小管上皮细胞中透明质烷（HA）和CD44分子的表达情况及其与草酸钙晶体黏附于肾小管的关系。方法将48只SD大鼠随机分为4组（每组12只），分别用含0．75％（vol／vol）乙二醇的饮水和普通饮水喂养，于喂养1d和5d后取其肾脏，用免疫组化法观察肾脏中HA和CD44的表达，并用偏光显微镜观察草酸钙晶体在肾小管中的滞留情况。结果喂养1d后，普通饮水组HA和CD44的阳性表达率均为25．0％，草酸钙晶体滞留比例为16．7％；乙二醇组分别为8．3％、16．7％和25．0％，两组差异均无统计学意义（均P〉0．05）。喂养5d后，普通饮水组HA和CD44的阳性表达率分别为33．3％和25．0％，草酸钙晶体滞留比例为16．7％；乙二醇组HA和CD44的阳性表达率及草酸钙晶体滞留比例分别为83．3％、75．0％和66．7％，明显高于普通饮水组（均P〈0．05），且组织中草酸钙晶体只黏附于表达有HA、CD44的肾小管上皮细胞的管腔面。结论受损大鼠肾小管上皮细胞表达HA和CD44分子与草酸钙晶体在肾小管中的滞留有密切关系。

Objective To study the expression of hyaluronan （HA） and CD44, a transmembrane glucoprotein and cell surface receptor of HA, in impaired renal tubular epithelial cells and relation thereof with the retention of calcium oxalate （CaOx） crystals in the renal tubule. Methods Forty-eight SD rats were randomly divided into four equal groups, ethylene glycol （EG） 1-day group, treated with drinking water containing 0.75% EG for 1 day, EG 5-day group, treated with drinking water containing 0.75% EG for 5 days, general drinking water 1 -day group, treated with tap water for 1 day, and general water 5-day group, treated with tap water for 5 days. The rats were killed 1 day or 5 days later respectively with their kidneys taken out. Immunohistochemistry was used to detect the expression of HA and CD44 in the renal tissues. Polarized light microscopy was used to detect the CaOx crystals in the renal tubules. Results The expression rates of HA and CD44, and proportion of crystal retention of the tap water 1-day group were 25.0% , 25.0%, and 16.7% respectively, all not significantly different from those of the EG 1-day group （8.3%, 16.7% , and 25.0% respectively, all P 〉0.05）. The expression rates of HA and CD44, and proportion of crystal retention of the tap water 5-day group were 33.3%, 25.0%, and 16.7% respectively, all significantly lower than those of the EG 5-day group （ 83.3% , 75.0%, and 66.7% respectively, all P 〈0.05）. Microscopy showed that the CaOx crystals adhered only to the injured tubular epithelial cells expressing HA and CD44 at their luminal membrane. Conclusion The expression of HA and CD44 by injured tubular cells seems to play a role in the retention of CaOx crystals in the kidney.