Histochemical studies on canine globoid cell leukodystrophy

Globoid cell (Krabbe) leukodystrophy (GLD) is a neurological disease described in humans and dogs. Central nervous system (CNS), liver and kidney from two cases were processed. Haematoxylin and eosin, Luxol-fast blue and lectin histochemistry were performed on paraffin embedded samples. Paraformaldheyde fixed tissues were infiltrated in glycol methacrylate and stained with Periodic Acid Schiff (PAS), Periodic Acid Silver Methenamine (PASM), Cresyl violet, Toluidine blue (TB), Alcian blue (AB) and Nile red (NR). On the same specimens, acid (PAC) and alkaline (PALK) phosphatase activities were tested. Pathological lesions were limited to CNS, with perivascular accumulation of PAS positive, BT methacromatic globoid cells. Histochemical staining for lectins revealed strong positivity using RCAI, RCAII and WGA, mild positivity using Con A. Krabbe cells exhibit a strong PAC and no PALK activities, and strong staining also with NR, in particular around the PAS/PASM positive deposits. Abnormal intracellular deposits were clearly visible in kidney glomeruli and distal tubules; resulting positive for BT but no metachromasy was evident. PAS/PASM positive deposits were unaffected by diastase treatment and non fluorescent after NR; no enzyme activity was detected. The observation of abnormal intracellular material was possible also in the liver parenchyma. Then the stored material in Krabbe cells is mainly composed by glycolipids not containing relevant sulphated groups. The abnormal intracellular deposits in the kidney and liver suggests the accumulation of material released from pathological degeneration of the CNS.