Podocyte specific knock out of selenoproteins does not enhance nephropathy in streptozotocin diabetic C57BL/6 mice.
BACKGROUND
Selenoproteins contain selenocysteine (Sec), commonly considered the 21st genetically encoded amino acid. Many selenoproteins, such as the glutathione peroxidases and thioredoxin reductases, protect cells against oxidative stress by functioning as antioxidants and/or through their roles in the maintenance of intracellular redox balance. Since oxidative stress has been implicated in the pathogenesis of diabetic nephropathy, we hypothesized that selenoproteins protect against this complication of diabetes.


METHODS
C57BL/6 mice that have a podocyte-specific inability to incorporate Sec into proteins (denoted in this paper as PodoTrsp-/-) and control mice were made diabetic by intraperitoneal injection of streptozotocin, or were injected with vehicle. Blood glucose, body weight, microalbuminuria, glomerular mesangial matrix expansion, and immunohistochemical markers of oxidative stress were assessed.


RESULTS
After 3 and 6 months of diabetes, control and PodoTrsp-/- mice had similar levels of blood glucose. There were no differences in urinary albumin/creatinine ratios. Periodic acid-Schiff staining to examine mesangial matrix expansion also demonstrated no difference between control and PodoTrsp-/- mice after 6 months of diabetes, and there were no differences in immunohistochemical stainings for nitrotyrosine or NAD(P)H dehydrogenase, quinone 1.


CONCLUSIONS
Loss of podocyte selenoproteins in streptozotocin diabetic C57BL/6 mice does not lead to increased oxidative stress as assessed by nitrotyrosine and NAD(P)H dehydrogenase, quinone 1 immunostaining, nor does it lead to worsening nephropathy.
Blauwkamp
Marsha N
MN
Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI 48109-5678, USA. mousman@umich.edu
Yu
Jingcheng
J
Schin
MaryLee A
MA
Burke
Kathleen A
KA
Berry
Marla J
MJ
Carlson
Bradley A
BA
Brosius
Frank C
FC
Koenig
Ronald J
RJ
D000818:Animals; D001835:Body Weight; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000235:genetics / Q000503:physiopathology; D003928:Diabetic Nephropathies / Q000378:metabolism / Q000503:physiopathology*; D017353:Gene Deletion; D020868:Gene Silencing; D020022:Genetic Predisposition to Disease; D006943:Hyperglycemia / Q000209:etiology; D007678:Kidney Glomerulus / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018384:Oxidative Stress; D050199:Podocytes / Q000378:metabolism; D012343:RNA, Transfer; D051140:Selenoproteins / Q000172:deficiency* / Q000235:genetics; D013997:Time Factors
D051140:Selenoproteins; D012343:RNA, Transfer