Zhang G, Oldroyd S D, Huang L H, Yang B, Li Y, Ye R, El Nahas A M
Sheffield Kidney Institute, Northern General Hospital, Sheffield, UK.
Exp Nephrol. 2001 Mar-Apr;9(2):71-80. doi: 10.1159/000052597.
BACKGROUND/AIMS: To examine the role of apoptosis in experimental unilateral ureteral obstruction (UUO).
Rat kidneys were examined 3, 7 and 11 days following UUO or sham operation (SO). Tissue was immunohistochemically stained for alpha-smooth muscle actin (alpha-SMA), proliferating cell nuclear antigen (PCNA), Bcl-2 and Bax proteins. Apoptotic analysis was carried out in kidney sections using in situ end labelling of endonuclease cleaved DNA.
The relative volume (Vv) of cortical interstitium and interstitial alpha-SMA increased progressively following UUO. ED1-positive monocytes/macrophages peaked at day 7 and significantly decreased at day 11. PCNA-positive cells in tubulointerstitium were significantly increased on day 3. Staining returned to the level of the SO group by day 11, meanwhile those in the interstitium remained much higher than baseline. TUNEL-positive cells were persistently raised following UUO. Transient tubular cell proliferation seemed unable to counteract the apoptosis since tubular atrophy was apparently present by day 11 of UUO. However, interstitial cell proliferation was high enough to overwhelm apoptosis, particularly with respect ot myofibroblasts, since alpha-SMA immunostaining and Vv remained elevated. The ratio of the number of PCNA-positive cells to apoptotic cells formed a predictive pattern for the staining score of interstitial alpha-SMA (R(2) = 47.23%, p < 0.05) and Vv (R(2) = 49.93%, p < 0.05). Tubular Bcl-2 immunostaining peaked on day 3, and then gradually decreased to baseline by day 11. The expression of Bax protein was inhibited on day 3 when compared with that of the SO group, but increased with time following UUO.
These findings suggest an important role for apoptosis and its regulatory proteins in the processes of tubular atrophy and fibrogenesis following UUO.
背景/目的：研究细胞凋亡在实验性单侧输尿管梗阻（UUO）中的作用。
在UUO或假手术（SO）后3、7和11天检查大鼠肾脏。组织进行免疫组织化学染色以检测α-平滑肌肌动蛋白（α-SMA）、增殖细胞核抗原（PCNA）、Bcl-2和Bax蛋白。使用原位末端标记法对肾切片进行凋亡分析，以检测核酸内切酶切割的DNA。
UUO后皮质间质的相对体积（Vv）和间质α-SMA逐渐增加。ED1阳性单核细胞/巨噬细胞在第7天达到峰值，在第11天显著下降。肾小管间质中PCNA阳性细胞在第3天显著增加。到第11天染色恢复到SO组水平，同时间质中的染色仍远高于基线。UUO后TUNEL阳性细胞持续增加。短暂的肾小管细胞增殖似乎无法抵消细胞凋亡，因为在UUO第11天时明显出现肾小管萎缩。然而，间质细胞增殖足够高以超过细胞凋亡，特别是对于肌成纤维细胞，因为α-SMA免疫染色和Vv仍然升高。PCNA阳性细胞数与凋亡细胞数的比值形成了间质α-SMA染色评分（R² = 47.23%，p < 0.05）和Vv（R² = 49.93%，p < 0.05）的预测模式。肾小管Bcl-2免疫染色在第3天达到峰值，然后在第11天逐渐降至基线。与SO组相比，Bax蛋白表达在第3天受到抑制，但在UUO后随时间增加。
这些发现表明细胞凋亡及其调节蛋白在UUO后肾小管萎缩和纤维化过程中起重要作用。
