Insulin Modulates Liver Function in a Type I Diabetes Rat Model

Background/aims: Several studies have been performed to unravel the association between diabetes and increased susceptibility to infection. This study aimed to investigate the effect of insulin on the local environment after cecal ligation and puncture (CLP) in rats.

Methods: Diabetic (alloxan, 42 mg/kg i.v., 10 days) and non-diabetic (control) male Wistar rats were subjected to a two-puncture CLP procedure and 6 h later, the following analyses were performed: (a) total and differential cell counts in peritoneal lavage (PeL) and bronchoalveolar lavage (BAL) fluids; (b) quantification of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL- 6, IL-10 and cytokine-induced neutrophil chemoattractant (CINC)-1 and CINC-2 in the PeL and BAL fluids by enzyme-linked immunosorbent assay (ELISA); (c) total leukocyte count using a veterinary hematology analyzer and differential leukocyte counts on stained slides; (d) biochemical parameters (urea, creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) by colorimetric analyses); and (e) lung, kidney, and liver morphological analyses (hematoxylin and eosin staining).

Results: Relative to controls, non-diabetic and diabetic CLP rats exhibited an increased in the concentration of IL-1β, IL-6, IL-10, CINC-1, and CINC-2 and total and neutrophil in the PeL fluid. Treatment of these animals with neutral protamine Hagedorn insulin (NPH, 1IU and 4IU, respectively, s.c.), 2 hours before CLP procedure, induced an increase on these cells in the PeL fluid but it did not change cytokine levels. The levels of ALT, AST, ALP, and urea were higher in diabetic CLP rats than in non-diabetic CLP rats. ALP levels were higher in diabetic sham rats than in non-diabetic sham rats. Treatment of diabetic rats with insulin completely restored ALT, AST, and ALP levels.

Conclusion: These results together suggest that insulin attenuates liver dysfunction during early two-puncture CLP-induced peritoneal inflammation in diabetic rats.