Alloxan has been widely used to produce
experimental diabetes mellitus syndrome. This compound causes
necrosis of pancreatic beta-cells and, as is well known, induces
oxidant free radicals which play a relevant role in the etiology and pathogenesis of both experimental and human
diabetes mellitus. Previously we have reported
hypoglycemic and antilipoperoxidative actions of
silymarin in serum and pancreatic tissue respectively. The aim of this study was to test whether
silymarin could reduce the
hyperglycemia and revert the pancreatic damage in
alloxan treated rats, tested with
silymarin in two protocols: using both compounds simultaneously for four or eight doses, or using the
compound 20 days after
alloxan administration for 9 weeks. Serum
glucose and
insulin were determined, and pancreatic fragments were used for histology and
insulin immunohistochemistry. Pancreatic islets were isolated to assess
insulin and Pdx1
mRNA expression by RT-PCR. Our results showed that 72 hours after
alloxan administration, serum
glucose increased and serum
insulin decreased significantly, whereas pancreatic tissue presented morphological abnormalities such as islet shrinkage, necrotic areas, loss of cell organization, widespread lipoid deposits throughout the exocrine tissue, and loss of beta cells, but
insulin and
glucagon immunoreactivity was scattered if any. In contrast the pancreatic tissue and both
insulin and
glucose serum levels of rats treated with
silymarin were similar to those of control animals. In addition,
insulin and
glucagon immunoreactive cells patterns in Langerhans islets were also normal, and normal
insulin and Pdx1
mRNA expression patterns were detected during pancreatic recovery in Langerhans islets. The overall results suggest that
silymarin induces pancreatic function recovery demonstrated by
insulin and
glucagon expression
protein and normoglycemia after
alloxan pancreatic damage in rats.