Immunohistochemical study of the pancreatic basement membrane in non obese diabetic mice (NOD) with spontaneous autoimmune insulitis.
The role of the basement membrane as an antigenic structure in autoimmune diseases is controversial. To determine possible structural changes in the endocrine pancreatic basement membrane (PBM) in autoimmune diabetes, we studied the expression of laminin in the islets of 42 NOD mice, aged between 4 to 42 weeks, as an animal model of spontaneous diabetes. Insular lymphocytic inflammatory infiltration of variable intensity was present in 24 of these mice. An immunohistochemical staining using the streptavidin-biotin-peroxidase technique was performed on paraffin-embedded tissue sections, with a polyclonal antilaminin antibody. Staining for laminin was restricted to the basement membrane. In islets with no inflammatory infiltration, laminin was observed as a thin, continuous and uniform brown layer, covering the pericapsular basement membrane of the islets and their capillaries. The continuity of the PBM was lost in the islets with insulitis and the immunostaining showed clearcut interruption and destruction, particularly when the islets were in contact with inflammatory infiltrate. Our findings suggest that the loss of integrity of the PBM in islets with inflammatory infiltrate could facilitate antigenic exposure contributing towards the start o f autoimmune DM in NODmice.
Pavin
E J
EJ
Department of Endocrinology, Anatomic Pathology, School of Medical Sciences, State University of Campinas, São Paulo, Brazil. ejpavin@globo.com
Pinto
G A
GA
Zollner
R L
RL
Vassallo
J
J
D000818:Animals; D001485:Basement Membrane / Q000378:metabolism / Q000473:pathology*; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D005260:Female; D007124:Immunoenzyme Techniques; D007515:Islets of Langerhans / Q000378:metabolism / Q000473:pathology*; D007797:Laminin / Q000378:metabolism; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D010195:Pancreatitis / Q000209:etiology / Q000378:metabolism / Q000473:pathology*
D007797:Laminin