Background: Acute kidney injury (AKI) is a major health problem associated with high morbidity and mortality rates.
Mesenchymal stem cells (MSCs) have revealed advantages for therapeutic use in medical practice. Microvesicles (MVs)
are membranous, cell-derived vesicles released by MSCs into their microenvironment. The conditioned medium (CM) is
the medium surrounding MSCs. Aim of the Work: This study aimed to investigate the therapeutic potential of MSCs, their CM and microvesicles (MVs) on experimentally induced acute kidney injury in rats. Materials and Methods: Fifty-five rats were divided into five groups: Group I (control group). Group II: given glycerol intramuscularly. Group III: given glycerol then MSCs. Group IV: given glycerol then CM. Group V: given glycerol then MVs. Kidney specimens were processed for H&E and Ki-67 staining and EM studies. Results: Subgroup IIA revealed vacuolation of the cytoplasm, flattening of the epithelial lining the tubules, extrusion of cytoplasm and nuclei into luminal spaces, deeply stained nuclei, and hyaline material in tubular lumina. EM examination of proximal and distal convoluted tubules showed multiple vacuoles, lysosomes, loss of continuity of apical cell membrane,presence of debris in the lumina and vacuolated mitochondria. Group IIB revealed poor improvement with persistence of most lesions. Groups III, VI and V showed amelioration of most of these lesions, and decrease in blood urea and serum creatinine levels. Conclusion: Mesenchymal stem cells, CM and MVs ameliorate induced AKI and with little differences in their effectiveness. CM and MVs can be used in treating diseases.