Low protein diet inhibits uric acid synthesis and attenuates renal damage in streptozotocin-induced diabetic rats.
OBJECTIVE
Several studies indicated that hyperuricemia may link to the worsening of diabetic nephropathy (DN). Meanwhile, low protein diet (LPD) retards exacerbation of renal damage in chronic kidney disease. We then assessed whether LPD influences uric acid metabolism and benefits the progression of DN in streptozotocin- (STZ-) induced diabetic rats.


METHODS
STZ-induced and control rats were both fed with LPD (5%) and normal protein diet (18%), respectively, for 12 weeks. Vital signs, blood and urinary samples for UA metabolism were taken and analyzed every 3 weeks. Kidneys were removed at the end of the experiment.


RESULTS
Diabetic rats developed into constantly high levels of serum UA (SUA), creatinine (SCr) and 24 h amounts of urinary albumin excretion (UAE), creatinine (UCr), urea nitrogen (UUN), and uric acid (UUA). LPD significantly decreased SUA, UAE, and blood glucose, yet left SCr, UCr, and UUN unchanged. A stepwise regression showed that high UUA is an independent risk factor for DN. LPD remarkably ameliorated degrees of enlarged glomeruli, proliferated mesangial cells, and hyaline-degenerated tubular epithelial cells in diabetic rats. Expression of TNF-α in tubulointerstitium significantly decreased in LPD-fed diabetic rats.


CONCLUSIONS
LPD inhibits endogenous uric acid synthesis and might accordingly attenuate renal damage in STZ-induced diabetic rats.
Department of Endocrinology, Guangzhou Red Cross Hospital, Medical College of Jinan University, No. 396 Tong Fu Zhong Road, Guangzhou 510220, China.
Jianmin
0000-0003-1364-9469
J
Ran
Department of Endocrinology, Guangzhou Red Cross Hospital, Medical College of Jinan University, No. 396 Tong Fu Zhong Road, Guangzhou 510220, China.
Jing
J
Ma
Department of Nephrology, Guangzhou Red Cross Hospital, Medical College of Jinan University, No. 396 Tong Fu Zhong Road, Guangzhou 510220, China.
Yan
Y
Liu
Clinical Institute of Nutrition, Guangzhou Red Cross Hospital, Medical College of Jinan University, No. 396 Tong Fu Zhong Road, Guangzhou 510220, China.
Rongshao
R
Tan
Department of Endocrinology, Guangzhou Red Cross Hospital, Medical College of Jinan University, No. 396 Tong Fu Zhong Road, Guangzhou 510220, China.
Houqiang
H
Liu
Department of Endocrinology, Guangzhou Red Cross Hospital, Medical College of Jinan University, No. 396 Tong Fu Zhong Road, Guangzhou 510220, China.
Gancheng
G
Lao
D000419:Albuminuria / Q000150:complications / Q000517:prevention & control; D000818:Animals; D049109:Cell Proliferation; D048429:Cell Size; D003921:Diabetes Mellitus, Experimental / Q000150:complications*; D003928:Diabetic Nephropathies / Q000517:prevention & control*; D018753:Diet, Protein-Restricted; D045604:Extracellular Fluid / Q000378:metabolism; D006943:Hyperglycemia / Q000517:prevention & control; D033461:Hyperuricemia / Q000150:complications / Q000178:diet therapy* / Q000378:metabolism / Q000473:pathology; D007668:Kidney / Q000473:pathology; D007684:Kidney Tubules / Q000378:metabolism / Q000473:pathology; D008297:Male; D050527:Mesangial Cells / Q000473:pathology; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013311:Streptozocin; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014527:Uric Acid / Q000097:blood / Q000378:metabolism* / Q000652:urine
D014409:Tumor Necrosis Factor-alpha; D014527:Uric Acid; D013311:Streptozocin