The Effect of Eight-week Caffeine Supplementation and High-Intensity Interval Training on the Serum Urea and Creatinine Levels and Morphological Changes of Glomerular Unit in Diabetic Rats

Glomerulonephritis is the one of disorders associated with diabetes. The present study was conducted to investigate the effect of 8-week high-intensity interval training (HIIT) and caffeine supplementation on the levels of serum creatinine (Cr) and blood urea nitrogen (BUN) and morphological changes of kidney tissue in diabetic rats.
50 diabetic rats as streptozotocin (STZ)-induced diabetic rats were randomly assigned to 5 equal groups including control, diabetic, diabetic + caffeine, diabetic + training, and diabetic + training + caffeine. The groups were given supplements (intraperitoneal injection of 70 mg/kg of caffeine powder for five days in each week) and underwent training (5 sessions including 6 to 12 times of 2-minutes training at the rate of 85-90% of maximal speed each week ) for 8 weeks. The serum Cr and BUN levels and the morphological changes of kidney tissue after 48 hours of the last training session were measured. Statistical analysis was performed by one- and two-way ANOVA (P<0.001).
It was revealed that HIIT reduced the levels of Cr (P=0.001) and BUN (P=0.013), as well as the urinary tract area (P=0.015) in diabetic rats. Although caffeine supplementation significantly reduced glomerular area (P=0.001) but increased BUN level (P=0.001) and Bowman's capsule (P=0.001) in them. There was a significant interaction between treatments regarding BUN level and urinary tract area changes (P=0.001, P=0.014, respectively).
HIIT and caffeine supplementation had significant effects on the serum Cr and BUN levels and morphological changes in rats' kidney tissues, but given doses and time of consumption of caffeine, as well as duration and intensity of training were more effective than the other indicators.