Fekete Andrea, Vannay Adám, Vér Agota, Rusai Krisztina, Müller Veronika, Reusz György, Tulassay Tivadar, Szabó Attila J
Research Group for Pediatrics and Nephrology, Hungarian Academy of Sciences, Budapest, Hungary.
Am J Physiol Renal Physiol. 2006 Oct;291(4):F806-11. doi: 10.1152/ajprenal.00080.2006. Epub 2006 Apr 11.
Previously, we demonstrated gender differences in Na-K-ATPase (NKA) expression and function after renal ischemia-reperfusion (I/R) injury (Sex differences in the alterations of Na(+), K(+)-ATPase following ischemia-reperfusion injury in the rat kidney. J Physiol 555: 471-480, 2004). Postischemic membrane destruction causes inhibition of NKA, whereas heat shock protein (HSP) 72 helps to preserve it. We tested the sex differences in postischemic expression of HSP72 and colocalization with NKA. The left renal pedicle of uninephrectomized female (F) and male (M) Wistar rats was clamped for 55 min followed by 2 (T2), 16 (T16), and 24 h (T24) of reperfusion. Uninephrectomized, sham-operated F and M rats served as controls. Postischemic blood urea nitrogen (BUN), serum creatinine, and renal histology were analyzed. HSP72 mRNA expression was detected by RT-PCR, protein levels by Western blot analysis. Fluorescent immunohistochemistry was performed to evaluate the localization of HSP72 and NKA alpha(1)-subunit. Postischemic BUN and creatinine were higher, and renal histology showed more rapid progression in M vs. F (P < 0.05). HSP72 mRNA expression was higher in F vs. M in control and in all I/R groups (P < 0.05). Similar changes were observed in HSP72 protein levels (F vs. M, P < 0.05, control, T2, T16, T24, respectively). Immunohistochemical localization of HSP72 and NKA alpha(1) was similar in control F and M. In postischemic F kidneys, the majority of NKA alpha(1) and HSP72 was colocalized on the basolateral membrane of tubular cells, whereas in M prominent staining was observed in the cytosol and apical domain. This study indicates that in female kidneys the higher basal and postischemic levels of HSP72 and different colocalization with NKA might contribute to the gender differences in renal I/R injury.
此前，我们已证明肾缺血再灌注（I/R）损伤后钠钾ATP酶（NKA）表达及功能存在性别差异（《大鼠肾脏缺血再灌注损伤后钠钾ATP酶变化的性别差异》。《生理学杂志》555: 471 - 480, 2004年）。缺血后膜破坏会抑制NKA，而热休克蛋白（HSP）72有助于维持其活性。我们检测了缺血后HSP72表达的性别差异以及与NKA的共定位情况。将未切除一侧肾脏的雌性（F）和雄性（M）Wistar大鼠的左肾蒂夹闭55分钟，随后分别再灌注2小时（T2）、16小时（T16）和24小时（T24）。未切除一侧肾脏的假手术雌性和雄性大鼠作为对照。分析缺血后血尿素氮（BUN）、血清肌酐及肾脏组织学情况。通过逆转录聚合酶链反应（RT-PCR）检测HSP72 mRNA表达，用蛋白质印迹分析检测蛋白水平。进行荧光免疫组织化学以评估HSP72和NKA α(1)亚基的定位。缺血后雄性大鼠的BUN和肌酐水平更高，且肾脏组织学显示其病变进展比雌性更快（P < 0.05）。在对照组及所有I/R组中，雌性大鼠的HSP72 mRNA表达均高于雄性（P < 0.05）。HSP72蛋白水平也观察到类似变化（雌性与雄性相比，P < 0.05，分别针对对照组、T2、T16、T24）。对照组雌性和雄性大鼠中HSP72和NKA α(1)的免疫组织化学定位相似。在缺血后雌性大鼠肾脏中，大多数NKA α(1)和HSP72共定位于肾小管细胞的基底外侧膜，而在雄性大鼠中，在细胞质和顶端区域观察到明显染色。本研究表明，雌性肾脏中较高的基础及缺血后HSP72水平以及与NKA不同的共定位情况可能导致肾I/R损伤中的性别差异。
