Aim: Early morphological alterations in the rat kidney and heart due to experimentally induced diabetes are described in order to evaluate the possible therapeutic role of low molecular weight heparin (LMWH; OP 2123/parnaparin).
Methods: Our findings concern the alterations observed in the rat kidney and heart because these are the organs (together with the retina) mainly involved in the early morphological angiopathic modifications associated with diabetic damage of organs and tissues. In diabetic animals treated with LMWH, the Periodic Acid-Schiff (PAS) reaction showed a slight decrease when compared with the diabetic control group. Photographs were submitted to the quantitative analysis of images using a Quantimet 500 Image Analyzer (Leica) equipped with specific software. The following parameters were measured: (1) total area occupied by alkaline phosphatase (AP)-positive capillaries; (2) number and diameter of AP-positive capillaries; (3) distribution and total area occupied by PAS-positive structures (related to the intensity of the reaction resulting from the different amount of mucopolysaccharides).
Results: LMWH treatment is efficient in preventing these modifications, above all in the kidney. The histological study of the heart and kidney shows no significant, relevant alterations. However, the histological study of the mucopolysaccharides in diabetic animals highlighted a tendency for the heart to accumulate these substances. LMWH treatment only modestly reduced this accumulation.
Conclusions: Previous evidence demonstrating a beneficial effect of therapy based on heparan sulphate proteoglycans and/or other heparin-like substances in insulin-dependent diabetes mellitus seems to be confirmed by our experimental results in different organs of adult rats. In fact, parnaparin treatment is effective (in our experience) for ameliorating the morphological pattern observed early in some diabetic tissues of rats and, above all, in the kidney.