CCAAT enhancer-binding proteins (CEBPs) play key roles in the metabolic regulation, cell transformation, and
inflammation. However, the expression and/or functions of CEBPs in rats with
hyperglycemia are still unclear. In the present study, we investigated the changes of CEBPs
protein in lung of the diabetic rats. The levels of C/EBPβ and C/EBPδ
protein were decreased in the lung isolated from
streptozotocin-induced diabetic rats (STZ-diabetic rats) as compared with that of normal rats. Exogenous
insulin at the dose sufficient to normalize the plasma
glucose of STZ-diabetic rats reversed the
protein levels of C/EBPβ and C/EBPδ in lung after a 4-day treatment. Similar results were also observed in STZ-diabetic rats that received the treatment of
phlorizin to reverse the plasma
glucose level for 4 days. Otherwise, the
protein level of C/EBPα in lung of the STZ-diabetic rats was similar as the normal rats. Also, the level of C/EBPα
protein in lung of the STZ-diabetic rat was not significantly changed by correction of plasma
glucose by exogenous
insulin or
phlorizin. In addition, we also cultured human lung cells (A-549) and rat lung cells (L2) in varies concentration of
D-glucose and
L-glucose to identify the effect of
glucose in expression of C/EBPs. The obtained results suggest that increase of plasma
glucose is related to the lower expression of C/EBPβ and C/EBPδ
proteins in the lung of STZ-diabetic rats. The changes of expression of C/EBPβ and C/EBPδ are not caused by changes of osmolarity but by
D-glucose itself.