Cytokine and Adhesion Molecule Expression Induced by Different Strains of Staphylococcus aureus in Type 1 Diabetic Rats: Role of Insulin

Abstract

Introduction: Staphylococcus aureus may provoke peritonitis and death, especially in immunocompromized individuals such as diabetic patients. We evaluated the role of insulin in S. aureus-induced peritoneal infection in diabetic and non-diabetic rats.Materials/Methods: Alloxan-diabetic male Wistar rats and their respective controls received intraperitoneal injections of different strains of S. aureus or sterile phosphate-buffered saline. After 3 days of infection, the first set of diabetic and non-diabetic rats received 4 and 1 IU, respectively, of neutral protamine Hagedorn insulin and were analyzed 8 h later. The second set of diabetic and non-diabetic rats received 4 and 1 IU, respectively, of insulin 2 h before intraperitoneal infection and a half dose of insulin at 5 p.m. for the next 2 days and were analyzed 16 h later. The following measurements were performed: (a) number of cells in the peritoneal lavage fluid (PeLF), white blood cell count, and blood glucose; (b) serum insulin and corticosterone; (c) cytokine levels in the PeLF; (d) expression of adhesion molecules in the vascular endothelium; and (e) microbicidal activity.Results: Diabetic rats showed an increased number of polymorphonuclear leukocytes (PMNs) and increased concentrations of CINC-1, IL-4, and IFN-γ in the PeLF after infection with the ATCC 25923 or N315 αHL+ strain. The mesenteric expression of PECAM-1 was increased after infection with the N315 HLA+ strain. ICAM-1 expression was increased with ATCC infection. Treatment of diabetic rats with a single dose of insulin restored CINC-1 levels in the PeLF for both strains; however, PMN migration, IL-4, and IFN-γ were restored in rats infected with the ATCC strain, whereas the PeLF concentrations of CINC-2, IL-1β, and IL-4 were increased in N315-infected animals. Insulin restored PMN migration and CINC-2 levels in the PeLF in ATCC-infected rats. After multiple treatments with insulin, the levels of IL-1β, IL-6, and IFN-γ were increased in the PeLF of diabetic rats after infection with either strain, and CINC-2 levels were restored in N315-infected animals.Conclusion: These results suggest that insulin distinctively modulates cytokine production or release, PMN leukocyte migration, and adhesion molecule expression during the course of peritonitis induced by different strains of S. aureus.

Pathogenesis of Staphylococcus haemolyticus on primary human skin fibroblast cells

“…In order to improve our knowledge of the interaction between the immune system and S. haemolyticus during the infection, we investigated the expression of IL1β, IL4, IL17, IFNγ, TNFα, TGFβ and IL10 by PBMCs infected with S. haemolyticus. S. haemolyticus and S. aureus induced human PBMCs to produce different cytokines at different relative levels after 6 and 24 hof infection.We observed a marked early inflammatory response, which is consistent with other reports that described a similar production of high levels of inflammatory mediators (IL1β, IL6, and TNFα) after S. aureus peritoneal infection [ 62 ]. This could be explained by the expression of different types of Toll-like receptors on PBMCs, which interacts with the bacteria and its products, leading to an increase in inflammatory cytokine release [ 63 ].…”

<p>Evaluation of Hypoglycemic Therapy Through Physical Exercise in n5STZ-Induced Diabetes Rats</p>

“…In this period, the organism is vulnerable to opportunistic infections. 36 Moreover, the increase in total number of leukocytes may occur due to the training protocol and not only an acute session of physical activity, which may be interpreted as a positive adaptation by the organism.…”