title: Insulin Prevents Hyperfiltration and Proteinuria but Not Glomerular Hypertrophy and Increases Mesangial Matrix Expansion in Diabetic Rats.
abstract: OBJECTIVE
  The aim of this work was to study the effect of 7 days of strict glycemic control with insulin on glomerular function and structure in streptozotocin (STZ)-diabetic rats.
  
  
  METHODS
  Three groups of adult male Fischer rats were studied: controls (n = 15), diabetics (n = 15), and insulin-treated diabetics (n = 15). Diabetes was induced by treating the rats with STZ (55 mg/kg i.p.). One week after the induction of diabetes, blood glucose, protein excretion rate (PER), glomerular filtration rate (GFR), and renal plasma flow (RPF) were estimated in each group. Furthermore, morphometric analysis was performed to estimate the tuft volume and changes in mesangial matrix area. The results are expressed as the mean ± SEM.
  
  
  RESULTS
  STZ diabetes caused significant increases in GFR (0.89 ± 0.1 to 1.21 ± 0.1 mL/min/100 g; p < 0.01) and RPF (1.78 ± 0.37 to 3.32 ± 0.6 mL/min/100 g; p < 0.05). Furthermore, the diabetic rats had higher glomerular volumes but mesangial matrix areas similar to controls. Insulin treatment prevented the increases in blood glucose (4.5 ± 0.2 mM), PER (66.1 ± 7.8 mg/day), GFR (0.6 ± 0.07 mL/min/100 g), and RPF (1.72 ± 0.36 mL/min/100 g), but did not prevent glomerular hypertrophy (21.7% increase), but induced mesangial matrix expansion (25% increase).
  
  
  CONCLUSIONS
  Insulin prevented the diabetes-induced hyperfiltration and proteinuria, but did not prevent glomerular growth, and induced mesangial expansion. Hyperglycemic episodes could be partly responsible for persistent glomerular growth and accelerated mesangial growth.
authors.affiliation: Department of Physiology, Faculty of Medicine, Kuwait University, Safat, Kuwait.
authors.forename: Slava
authors.initials: S
authors.lastname: Malatiali
authors.forename: Issam
authors.initials: I
authors.lastname: Francis
authors.forename: Mario
authors.initials: M
authors.lastname: Barac-Nieto
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D001835:Body Weight; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000503:physiopathology* / Q000652:urine; D005919:Glomerular Filtration Rate / Q000187:drug effects*; D006984:Hypertrophy; D007328:Insulin / Q000494:pharmacology*; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D008297:Male; D050527:Mesangial Cells / Q000187:drug effects* / Q000473:pathology; D011507:Proteinuria / Q000188:drug therapy / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D013311:Streptozocin
chemical_list: D001786:Blood Glucose; D007328:Insulin; D013311:Streptozocin