Renal lymphatic ligation aggravates renal dysfunction through induction of tubular epithelial cell apoptosis in mononephrectomized rats

AIMS: To further explore the mechanisms of apoptosis in mononephrectomized rats with renal lymph circulation disorder. METHODS: Animals were divided into three groups: rats with left renal lymph ligation and right nephrectomy (KL), rats with only right nephrectomy (KN) and sham-operated rats (sham). 24-h proteinuria and serum creatinine level were monitored. Indexes of oxidative stress were measured. Renal apoptosis was examined. Further biochemical analysis was provided using real-time PCR, western blot and Elisa techniques. RESULTS: Our results showed that renal lymphatic ligation induced renal tubular epithelial cell apoptosis and aggravated renal dysfunction in mononephrectomized rats. In addition, renal lymphatic ligation increased the activities of caspase-3, caspase-8 and caspase-9. Further investigation of mechanisms showed that renal lymphatic ligation up-regulated Fas expression, increased the ratio of Bax/Bcl-2, and also increased the levels of reactive oxygen species (ROS), malondialdehyde (MDA) while reducing superoxide dismutase (SOD) activity. CONCLUSION: These results indicated that disturbance of renal lymphatic circulation might lead to tubular epithelial cell apoptosis through activation of intrinsic and extrinsic apoptotic pathways, suggestive of an essential role of renal lymphatic circulation in the maintenance of tubular integrity and function.