Currently, there is no effective method to prevent renal interstitial
fibrosis after
acute kidney injury (AKI). In this study, we established and screened a new renal interstitial
fibrosis rat model after
cisplatin-induced AKI. Our results indicated that rats injected with 4 mg/kg
cisplatin once a week for two weeks after firstly administrated with 6.5 mg/kg loading dose of
cisplatin could set up a more accurate model reflecting AKI progression to renal interstitial
fibrosis. Then, we investigated the effects and possible mechanisms of human umbilical cord blood mononuclear cells (hUCBMNCs) on renal tubular interstitial
fibrosis after
cisplatin-induced AKI. In rats injected with hUCBMNCs for four times, level of
matrix metalloproteinase 7 (MMP-7) in serum and urine, urinary
albumin/
creatinine ratio, tubular pathological scores, the relative
collagen area of the tubulointerstitial region, endoplasmic reticulum dilation and the mitochondrial ultrastructural damage were significantly improved. The level of
reactive oxygen species, α-smooth muscle actin (α-SMA), [NOD]-like pyrin domain containing
protein 3 and cleaved-
Caspase 3 in renal tissue decreased significantly. However, in rats injected with hUCBMNCs for two times, no significant difference was discovered in MMP-7 levels and urinary
albumin/
creatinine ratio. Although expression of α-SMA and the percentage areas of
collagen staining in tubulointerstitial tissues were ameliorated in rats injected with hUCBMNCs for two times, the effects were significantly weaker than those in rats injected with hUCBMNCs for four times. Taken together, our study constructed a highly efficient, duplicable novel rat model of renal
fibrosis after
cisplatin-induced AKI. Multiple
injections of hUCBMNCs may prevent renal interstitial
fibrosis after
cisplatin-induced AKI.