Xiao Bo, Ma Lu-lin, Xiao Chun-lei, Lu Min, Xu Wei, Huang Yi, Zhang Shu-dong, Hou Xiao-fei
Department of Urology, Peking University Third Hospital, Beijing 100191, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2011 Aug 18;43(4):525-30.
To investigate whether there is a protective mechanism in exogenous magnesium ions supplement in renal ischemia reperfusion injury(IRI ), and to study the expression of heat shock protein 70 (HSP70) and HSP70-mRNA in the reperfusion injury.
A total of 90 male Japanese white rabbits (1.8-2.0 kg) were divided into three groups: ischemia reperfusion group (I-R), MgSO4 pretreatment group and sham operation group. The right kidney was cut through median abdominal incision to make solitary kidney model. The left renal artery was blocked for 1 h in I-R group and MgSO₄ group. 2.5% MgSO₄ 1 mL/(kg×h) was given through ear vein before the artery was blocked and during the blockeage in the MgSO₄ group. the kidney cortex tissue was taken 1, 2, 4, 24, 48 and 72 h after reperfusion. Immunohistochemical examination was used to determine the HSP70 expression. A modified quantitative Real time-PCR was used to quantitate HSP70-mRNA in the three groups. Pathological examination was also used to confirm the results.
Real time-PCR showed that HSP70-mRNA began to increase at the end of 1 h, and reached the peak at the end of 2 h in both I-R and MgSO₄ groups, but expression in I-R group which was remarkably higher than that in the MgSO₄ group at the end of 2 h and 4 h ( P<0.05). HSP70-mRNA levels decreased rapidly at the end of 24 h. In I-R group, moderate HSP70 expression could be seen in the proximal tubules during immunohistochemical examination after reperfusion for 24 h and 48 h. By contrast, there was weak HSP70 expression in the MgSO₄ group 24 h and negative 48 h after reperfusion. Epithelial shedding, border brush, inflammatory cell infiltration and protein casts were serious after 24 to 48 h reperfusion, while only slight tubular cell shedding and necrosis could be found in the MgSO₄ group at the matched time.
Magnesium supplement can significantly relieve the renal ischemia reperfusion injury. It can inhibit the upregulated expression of HSP70 and HSP70-mRNA in vivo, which demonstrates that the expression of HSP70 is not necessary in the protective mechanism.
探讨外源性补充镁离子在肾缺血再灌注损伤（IRI）中是否存在保护机制，并研究热休克蛋白70（HSP70）及其mRNA在再灌注损伤中的表达情况。
选取90只体重1.8 - 2.0 kg的雄性日本大耳白兔，分为三组：缺血再灌注组（I-R）、硫酸镁预处理组和假手术组。经腹部正中切口切除右侧肾脏制成单肾模型。I-R组和硫酸镁组阻断左肾动脉1小时。硫酸镁组在动脉阻断前及阻断期间经耳静脉给予2.5%硫酸镁1 mL/（kg×h）。再灌注后1、2、4、24、48及72小时取肾皮质组织。采用免疫组织化学法检测HSP70表达。采用改良的实时定量PCR法对三组中HSP70-mRNA进行定量分析。同时进行病理检查以验证结果。
实时PCR显示，I-R组和硫酸镁组中HSP70-mRNA在1小时末开始升高，2小时末达到峰值，但在2小时末和4小时末I-R组的表达明显高于硫酸镁组（P<0.05）。24小时末HSP70-mRNA水平迅速下降。免疫组织化学检查显示，再灌注24小时和48小时后，I-R组近端小管可见中等强度的HSP70表达。相比之下，硫酸镁组再灌注24小时时HSP70表达较弱，48小时时为阴性。再灌注24至48小时后，上皮脱落、刷状缘、炎性细胞浸润及蛋白管型严重，而在相同时间硫酸镁组仅见轻微的肾小管细胞脱落和坏死。
补充镁可显著减轻肾缺血再灌注损伤。它能抑制体内HSP70及其mRNA的上调表达，表明HSP70的表达在保护机制中并非必需。
