Protective effect of adipose-derived mesenchymal stem cells against acute kidney injury induced by ischemia-reperfusion in Sprague-Dawley rats

Abstract

Acute kidney injury (AKI) is a complex clinical condition associated with significant morbidity and mortality and lacking effective management. Ischemia-reperfusion injury (IRI) remains one of the leading causes of AKI in native and transplanted kidneys. The aim of this study was to evaluate the efficacy of adipose-derived mesenchymal stem cells (ADSCs) in the prevention of renal IRI in rats. The study was conducted on male Sprague-Dawley rats (n=72) weighing 250-300 g. Rats were randomly assigned to three main groups: i) Sham-operated control group (n=24); ii) positive control group, in which rats were subjected to IRI and were administered culture media following 4 h of IRI (n=24); and iii) ADSC group (n=24), in which rats were administered 1×10⁶ ADSCs via the tail vein following 4 h of IRI. Each main group was further divided according to the timing after IRI into four equal-sized subgroups. Renal function was tested via the measurement of serum creatinine levels and creatinine clearance. In addition, malondialdehyde (MDA) levels were determined in serum and renal tissue homogenate as an indicator of oxidative stress. Histopathological changes were analyzed in different regions of the kidney, namely the cortex, outer stripe of the outer medulla (OSOM), inner stripe of the outer medulla (ISOM) and inner medulla. In each region, the scoring system considered active injury changes, regenerative changes and chronic changes. The ADSCs were assessed and their differentiation capability was verified. IRI resulted in a significant increase in serum creatinine, serum and tissue MDA levels and a significant reduction in creatinine clearance compared with those in sham-operated rats,. These changes were attenuated by the use of ADSCs. The prominent histopathological changes in the cortex, ISOM and OSOM were reflected in the injury score, which was significantly evident in the positive control group. The use of ADSCs was associated with significantly lowered injury scores at days 1 and 3; however, no significant effect was observed on day 7. These results indicate that the use of ADSCs ameliorates renal injury and dysfunction associated with IRI in rats.

Keywords: acute kidney injury; adipose derived mesenchymal stem cell; ischemia reperfusion injury; rats.

Figure 1.

Differentiation of rat adipose-derived mesenchymal stem cells (ADSCs): (A) Undifferentiated and (B) osteogenically differentiated rat ADSCs stained with Alizarin Red. (C) Undifferentiated and (D) adipogenically differentiated rat ADSCs stained with Oil Red O (magnification, ×4).

Figure 2.

Histopathological changes: Effect of adipose-derived mesenchymal stem cells (ADSCs). (A) The ischemia-reperfusion group shows diffusely necrotic tubules in the outer stripe outer medulla (OSOM) 24 h after ischemia-reperfusion injury (IRI) (magnification, ×100). Histology in the ADSC group shows prominent regenerative changes at 3 days after IRI at the OSOM in the form of (B) solid sheets (magnification, ×40), (C) mitotic figures as indicated by the arrow (magnification, ×400), (D) regenerating cells with large nuclei (magnification, ×400) and (E) intraluminal papillary cellular proliferation (magnification, ×400), while (F) the inner medulla shows proliferating solid sheets of monotonous cells (magnification, ×400).