Acute lung histopathological alterations induced by acute kidney injury in rats subjected to bilateral or unilateral nephrectomy and bilateral or unilateral renal ischemia/reperfusion


Authors:

Zinab Karimi1, Seyed Mostafa Shid Moosavi1, Farzaneh Ketabchi1 1. Department of Physiology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran

Correspondence:

Zinab Karimi zkarimi@sums.ac.ir

Introduction: Acute kidney injury (AKI) is usually associated with acute lung injury (ALI) in the intensive care unit, with high mortality rate. To determine the mediators and histopathological changes in ALI induced by AKI, animal models of renal ischemia with uremia (bilateral renal ischemia; BIR), renal ischemia without uremia (unilateral renal ischemia; UIR), uremia without renal ischemia (bilateral nephrectomy, BNX), and without uremia and renal ischemia (unilateral nephrectomy, UNX) have been used in this study.

Methods: Thirty male Sprague-Dawley rats, weighing 250-300g,were divided into 6groups. Animals had a 1-h bilateral or 2-h unilateral renal ischemia followed by 24-h reperfusion in BIR and UIR groups, respectively, and a 24-h period after bilateral or unilateral nephrectomy in BNX and UNX groups, respectively. There were also sham and control groups of rats with and without sham-operation, respectively. At the end of each experiment, a 1-mL blood sample was taken and its plasma was preserved, and then lung and kidneys were removed for later histopathological evaluation.

Results: Plasma creatinine and urea were intensively elevated only in the BIR and BNX groups. Ischemic kidney of the UIR group and both kidneys of the BIR group showed Bowman's space enlargement and sever tubular cell injury, vascular congestion, and intratubular cast in the cortex and medulla, which were higher in the latter group. The lung tissue of the UNX and UIRgroup had relatively normal appearance. But, there was an obvious ALI in the BIR and BNX groups, which was characterized by alveolar hemorrhage, vascular congestion and largely increased thickness of respiratory membrane.

Conclusion: UNX and UIR, which were without uremia, do not induce ALI. However, the development of uremic condition during 24 h after induction of AKI with ischemic kidneys (BIR) or without kidneys (BNX) can lead to ALI.

Keywords: Acute kidney injury; Acute lung injury; Renal ischemia/reperfusion; Nephrectomy.