ObjectiveTo explore the mechanism of renal tubular epithelial cell apoptosis induced by endoplasmic reticulum stress in rats with intermittent hypoxia (IH) and the intervention effect of losartan.MethodsSixty SPF grade healthy male SD rats were randomly divided into four groups (15 rats in each group), namely as group A (control group), group B (IH group), group C (IH+losartan group), and group D (IH+saline group). The group C and D were intraperitoneally injected with losartan 30 mg/kg and the same dose of saline 30 minutes daily before the experiment, and then the group B, C and D were placed in the intermittent hypoxia chamber. After 6 weeks of modeling, serum of the rats was sampled to detect the renal function. Hematoxylin-eosin staining was used to observe histomorphological changes of the kidney; transmission electron microscopy was used to observe ultrastructural changes of the kidney; TUNEL was used to detect apoptotic index of the renal tubular epithelial cells; and RT-PCR method was used to detect expressions of caspase-12, JNK and CHOP mRNA in the kidney.ResultsThe differences of renal function among these four groups were statistically significant (all P<0.05). Hematoxylin-eosin staining and transmission electron microscopy showed the histomorphological and ultrastructural changes of the kidneys in group B, C and D compared with group A, and the damages in group B and D were more significant. TUNEL results showed that the apoptotic index of renal tubular epithelial cells in group B and D was significantly higher than that in group A (P<0.01), while that in group C was significantly lower than that in group B and D (all P<0.01). RT-PCR results showed that caspase-12, JNK and CHOP mRNA expressions were significantly higher in group B and D than those in group A (all P<0.01); caspase-12 mRNA expression was significantly lower in group C than that in group B and D (P<0.01; P<0.05); and CHOP mRNA expression was significantly lower in group C than that in group B and D (all P<0.01).ConclusionsIH may induce apoptosis of renal tubular epithelial cells by activating endoplasmic reticulum stress through caspase-12, JNK and CHOP. Losartan has protective effects on the kidney of rats with intermittent hypoxia. Its mechanism may be related to the inhibition of apoptotic pathways mediated by endoplasmic reticulum stress.