Aims/hypothesis  

An increasing amount of evidence indicates that mannose-binding lectin (MBL) plays a role in the development of diabetic nephropathy. The main objective of the study was to analyse whether MBL influences the effects of diabetes on the kidneys.

Materials and methods  

In one group of wild-type mice and in one group of MBL double knockout mice we induced diabetes by the use of streptozotocin as a model of type 1 diabetes. Two groups of non-diabetic mice, wild-type and MBL knockout, were also included. By two-way ANOVA we evaluated if MBL modulated the effects of diabetes by testing the interaction between diabetes and MBL.

Results  

MBL interacted with the effects of diabetes on three outcome measures: kidney weight (p < 0.001), urinary albumin excretion (p = 0.001) and the expression of collagen IVα1 (Col4a1) mRNA (p = 0.002). This means that the effects that diabetes normally has on these parameters were significantly modified by MBL. MBL showed a tendency to interact with the effects of diabetes on glomerular basement membrane thickness and total mesangial volume (p = 0.065 and p = 0.063, respectively). Glomerular volume and total mesangial volume were significantly smaller in animals lacking MBL than in wild-type animals (p = 0.006 and p = 0.047, respectively).

Conclusions/interpretation  

These findings, for the first time, show that the degree of kidney alteration as a consequence of diabetes is modified by MBL. These findings support a pivotal role of MBL in the development of diabetic kidney disease.