Abstract:

Objective To discuss the protective effect of polygonatum odoratum polysaccharide （POP） on the mice with cisplatin-induced acute kidney injury（AKI）， and to clarify its possible mechanism. Methods Forty male C57BL/6 mice were randomly divided into control group， model group， POP group，and ferroptosis inducer Erastin combined with POP（Erastin+POP） group，and there were 10 mice in each group.The mice in POP group and Erastin+POP group were given intragastric administration of POP （400 mg·kg^-1）， and on the 7th day，the mice in model group， POP group， and Erastin+POP group were intraperitoneally injected with cisplatin （20 mg·kg^-1） to establish the AKI models，the mice in control group were injected with the same volume of normal saline， and the mice in Erastin+POP group were intraperitoneally injected with Erastin （40 mg·kg^-1） one day in advance （on the 6th day of the experiment）. After 9 d， the mice were killed and the serum and kidney tissue were collected， and the levels of serum creatinine （Scr） and blood urea nitrogen （BUN） and the levels of malondialdehyde （MDA） and glutathione （GSH） in kidney tissue of the mice in various groups were detected by kit； HE staining was used to observe the pathomorphology of kidney tissue of the mice in various groups； the expression levels of ferroptosis suppressor protein 1 （FSP1）， ferritin heavy chain 1 （FTH1）， and glutathione peroxidase 4 （GPX4） proteins in kidney tissue of the mice in various groups were detected by immunohistochemistry； Western blotting method was used to detect the expression levels of nuclear factor-E2-related factor 2 （Nrf2） and heme oxygenase-1 （HO-1） proteins in kidney tissue of the mice in various groups. Results Compared with control group， the levels of Scr and BUN of the mice in model group were significantly increased （P<0.01）， the level of MDA in kidney tissue was significantly increased （P<0.01）， and the level of GSH was significantly decreased （P<0.01）； most kidney tubules were dilated， the epithelial cells were swollen，the vacuolar degeneration and epithelial cells fell off， and the protein-like tubules could be seen in the lumen； the expression levels of FSP1， FTH1， GPX4， Nrf2， and HO-1 proteins in kidney tissue were decreased significantly （P<0.05 or P<0.01）. Compared with model group， the levels of Scr and BUN of the mice in POP group were significantly decreased （P<0.01）， the level of MDA in kidney tissue was significantly decreased （P<0.01）， and the level of GSH was significantly increased （P<0.01）； the dilatation of kidney tubular lumen， epithelial cell swelling， vacuolar degeneration，and epithelial cell exfoliation were decreased； the expression levels of FSP1， FTH1， GPX4， Nrf2，and HO-1 proteins in kidney tissue of the mice in POP group were significantly increased （P<0.05 or P<0.01）. Compared with POP group， the levels of Scr and BUN of the mice in Erastin +POP group were significantly increased （P<0.01）， the level of MDA in kidney tissue was increased （P<0.05）， and the level of GSH was significantly decreased （P<0.01）； the pathological injury of kidney tissue was aggravated obviously； the expression levels of FSP1， FTH1， GPX4， Nrf2， and HO-1 proteins in kidney tissue were significantly decreased （P<0.05 or P<0.01）. Conclusion POP can reduce the AKI in the mice induced by cisplatin， and its mechanism may be related to the inhibitory effect of POP on the ferroptosis induced by cisplatin.

Key words: Polygonatum odoratum polysaccharide, Cisplatin, Acute kidney injury, Ferroptosis, Nuclear factor-E2-related factor 2