Effects of 4-phenylbutyric acid on the process and development of diabetic nephropathy induced in rats by streptozotocin: regulation of endoplasmic reticulum stress-oxidative activation.
Oxidative stress may contribute to the pathogenesis of diabetic nephropathy (DN), although the precise regulatory mechanism is still unclear. Recent reports have shown that chemical molecular chaperone 4-phenylbutyric acid (4-PBA) can suppress oxidative stress by attenuating endoplasmic reticulum (ER) stress. We therefore hypothesized that 4-PBA could provide renoprotection through the suppression of oxidative stress in DN rats. Male Sprague-Dawley (SD) rats were randomly divided into three groups: a normal control (NC) group, a streptozotocin (STZ)-induced DN model group, and a DN plus 4-PBA (1g/kg) treatment group. At the end of 4, 8, and 12 weeks, hydroxyproline content, NADPH oxidase activity and the expression of phosphorylation of inositol-requiring enzyme-1alpha (p-IRE1alpha), p47phox, nitrotyrosine (NT) and NF-E2-related factor 2 (Nrf2) in the kidneys of all rats were determined; malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity in serum and urine were also detected; renal nuclear factor kappaB (NF-kappaB) activity in all of the rats was examined at the end of 12 weeks. Compared with the NC group, the DN rats showed a significant increase in hydroxyproline content, NADPH oxidase activity, NF-kappaB activity, the expression of p-IRE1alpha, p47phox, NT and Nrf2 in renal tissue; markedly, MDA levels were higher and SOD activity was lower in serum and urine of DN rats than in NC rats for the indicated time. These alterations were inhibited by the administration of 4-PBA. These findings first demonstrated that treatment with 4-PBA significantly inhibits the process and development of diabetic nephropathy in rats through the regulation of ER stress-oxidative activation.
Luo
Zhi-Feng
ZF
Institute of Nephrology of Chongqing and Department of Nephrology, Xinqiao Hospital, The Third Military Medical University, Chongqing 400037, People's Republic of China.
Feng
Bing
B
Mu
Jiao
J
Qi
Wei
W
Zeng
Wei
W
Guo
Yan-Hong
YH
Pang
Qi
Q
Ye
Zi-Lin
ZL
Liu
Li
L
Yuan
Fa-Huan
FH
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use*; D001806:Blood Urea Nitrogen; D003404:Creatinine / Q000097:blood; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy*; D003928:Diabetic Nephropathies / Q000188:drug therapy*; D004721:Endoplasmic Reticulum / Q000187:drug effects* / Q000378:metabolism; D006909:Hydroxyproline / Q000032:analysis; D007668:Kidney / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D008315:Malondialdehyde / Q000097:blood / Q000652:urine; D019255:NADPH Oxidases / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D010654:Phenylbutyrates / Q000494:pharmacology / Q000627:therapeutic use*; D011507:Proteinuria / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000097:blood / Q000652:urine
D000975:Antioxidants; D010654:Phenylbutyrates; D008315:Malondialdehyde; C075773:4-phenylbutyric acid; D003404:Creatinine; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; D006909:Hydroxyproline