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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Streptozotocin-induced diabetes mellitus affects lysosomal enzymes in rat liver

Full text
Author(s):
G.B. Peres [1] ; M.A. Juliano [2] ; J.A.K. Aguiar [1] ; Y.M. Michelacci [1]
Total Authors: 4
Affiliation:
[1] Univ Fed Sao Paulo, Escola Paulista Med, Dept Bioquim, Sao Paulo - Brazil
[2] Univ Fed Sao Paulo, Escola Paulista Med, Dept Biofis, Sao Paulo - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Brazilian Journal of Medical and Biological Research; v. 47, n. 6, p. 452-460, 2014-05-09.
Abstract

It has been previously shown that dextran sulfate administered to diabetic rats accumulates in the liver and kidney, and this could be due to a malfunction of the lysosomal digestive pathway. The aim of the present study was to evaluate the expression and activities of lysosomal enzymes that act upon proteins and sulfated polysaccharides in the livers of diabetic rats. Diabetes mellitus was induced by streptozotocin in 26 male Wistar rats (12 weeks old), while 26 age-matched controls received only vehicle. The livers were removed on either the 10th or the 30th day of the disease, weighed, and used to evaluate the activity, expression, and localization of lysosomal enzymes. A 50-60% decrease in the specific activities of cysteine proteases, especially cathepsin B, was observed in streptozotocin-induced diabetes mellitus. Expression (mRNA) of cathepsins B and L was also decreased on the 10th, but not on the 30th day. Sulfatase decreased 30% on the 30th day, while glycosidases did not vary (or presented a transitory and slight decrease). There were no apparent changes in liver morphology, and immunohistochemistry revealed the presence of cathepsin B in hepatocyte granules. The decrease in sulfatase could be responsible for the dextran sulfate build-up in the diabetic liver, since the action of sulfatase precedes glycosidases in the digestive pathway of sulfated polysaccharides. Our findings suggest that the decreased activities of cathepsins resulted from decreased expression of their genes, and not from general lysosomal failure, because the levels of glycosidases were normal in the diabetic liver. (AU)

FAPESP's process: 13/07109-8 - Expression and activity of lysosomal enzymes in cultured cells exposed to conditions that mimic diabetes
Grantee:Yara Maria Corrêa da Silva Michelacci
Support Opportunities: Regular Research Grants
FAPESP's process: 10/16022-5 - Lysosomal enzymes, metalloproteinases and proteoglycans in Diabetes mellitus
Grantee:Yara Maria Corrêa da Silva Michelacci
Support Opportunities: Regular Research Grants
FAPESP's process: 09/11817-2 - Expression of lysosomal enzymes and metalloproteases in experimental model of diabetes mellitus
Grantee:Giovani Bravin Peres
Support Opportunities: Scholarships in Brazil - Master