Effect of colquhounia root tablet on expression of tight junction proteins claudin-5 and ZO-1 in renal tissues of rats with acute lung injury

Objective To evaluate the effect of colquhounia root tablet on the expression of tight junction proteins claudin-5 and ZO-1 in the renal tissues of rats with acute lung injury (ALI). Methods Twenty-four healthy male Sprague-Dawley rats, weighing 250-300 g, were randomly divided into 3 groups (n = 8 each) using a random number table: control group (group C), ALI group; and colquhounia root tablet group (group H). Oleic acid 0.04 ml/kg was injected into the trail vein to establish the model of ALI.In group H, colquhounia root tablet 600 mg·kg-1·d-1 was instilled into the stomach of each rat for 10 consecutive days, and oleic acid was injected at 1 h after instillation on 10th day.Blood samples were collected from the abdominal aorta at 6 h after injection of oleic acid for determination of plasma creatine (Cr) and blood urine nitrogen (BUN) concentrations.The animals were then sacrificed.The lungs were removed for determination of wet/dry lung weight ratio (W/D ratio), and for examination of the pathological changes.The kidneys were removed for determination of the expression of claudin-5 and ZO-1 (by immunohischemistry assay and Western blot) and for examination of the pathological changes.The damage to the renal tubules was scored. Results Compared with group C, W/D ratio, plasma Cr and BUN concentrations, and renal tubular damage score were significantly increased, and the expression of claudin-5 and ZO-1 was down-regulated in group ALI (P<0.01). Compared with group ALI, W/D ratio, plasma Cr and BUN concentrations, and renal tubular damage score were significantly decreased, and the expression of claudin-5 and ZO-1 was up-regulated in group H (P<0.01). The pathological changes of lungs and kidneys were significantly attenuated in group H as compared with group ALI. Conclusion Colquhounia root tablet can attenuate kidney injury through up-regulating the expression of tight junction proteins claudin-5 and ZO-1 in the renal tissues of rats with ALI. Key words: Tripterygium; Respiratory distress syndrome, adult; Kidney; Connexins