Study On Cytotoxicity Of Renin Inhibitors On Human Kidney 2 (HK-2) Cells

The renin inhibitor is an effective method for treatment of hypertension. Study on cytotoxicity of renin inhibitors on human cells can provide available guidelines to queantify their effects.The study evaluated the cytotoxicity of the renin inhibitors using human proximal renal tubular epithelial cells (HK-2). Doxorubicin as a positive compound and the renin inhibitors including Aliskiren were evaluated for their potential toxicity. For toxicity evaluations, cell viability (Resazurin assay) as marker of metabolic activity, membrane leakage of lactate dehydrogenase (LDH assay) as marker of necrosis, Caspase 3/7 activity assay as marker of apoptosis, and phospholipidosis in the cells were assessed under doxorubicin and renin inhibitors exposed conditions.The results on HK-2 cells showed that doxorubicin had obvious cytotoxic effect on HK-2 cells. There was a significant reverse-correlation between cell viability (metabolic activity) and LDH or Caspase 3/7 activity (R2=0.9854 and R2=0.9904), while a significant positive-correlation between Caspase 3/7 activity and LDH activity (R2=0.9988). Doxorubicin could induce the accumulation of intracellular phospholip, cause mitochondrial dysfunction, then activate the apoptotic program rapidly, cause cell necrosis, and exhibited highly cytotoxicity on HK-2 cells.The results on HK-2 cells also showed that Aliskiren was not cytotoxicity in HK-2 cells, by no changes in cell viability, caspase activities or LDH leakage, but could induce slight phospholipidosis. Compound R397 was highly cytotoxicity as evidenced by significant changes in morphology, serious phospholipidosis and cell viability in high dosage, but R397 did not induce apoptosis or necrosis. R407 could inhibit HK-2 cell viability, cause cell membrane damage and induce cell necrosis. R404 and R438 could inhibit cell metabolic activity. R421, R581 and R585 induced both apoptosis and necrosis on HK-2 cells, in the meantime R423, R425, R484 and R522 induced necrosisi, but all of them did not inhibit cell viability in high dosage. R423, R425 and R522 could also induce serious phospholipidosis in high dosage. Except of the above, the other 12 compounds showed no inhibition of cell viability, did not induce apoptosis or necrosis, but they could induce phospholipidsis similar or slightly than Aliskiren in the highest dose.