Kinetics of TNF-alpha and IFN-gamma mRNA expression in islets and spleen of NOD mice

Abstract

Insulin-dependent diabetes mellitus is caused by autoimmune destruction of pancreatic ß cells. Non-obese diabetic (NOD) mice spontaneously develop diabetes similar to the human disease. Cytokines produced by islet-infiltrating mononuclear cells may be directly cytotoxic and can be involved in islet destruction coordinated by CD4+ and CD8+ cells. We utilized a semiquantitative RT-PCR assay to analyze in vitro the mRNA expression of TNF-a and IFN-g cytokine genes in isolated islets (N = 100) and spleen cells (5 x 10 5 cells) from female NOD mice during the development of diabetes and from female CBA-j mice as a related control strain that does not develop diabetes. Cytokine mRNAs were measured at 2, 4, 8, 14 and 28 weeks of age from the onset of insulitis to the development of overt diabetes. An increase in IFN-g expression in islets was observed for females aged 28 weeks (149 ± 29 arbitrary units (AU), P<0.05, Student t-test) with advanced destructive insulitis when compared with CBA-j mice, while TNF-a was expressed in both NOD and CBA-j female islets at the same level at all ages studied. In contrast, TNF-a in spleen was expressed at higher levels in NOD females at 14 weeks (99 ± 8 AU, P<0.05) and 28 weeks (144 ± 17 AU, P<0.05) of age when compared to CBA-j mice. The data suggest that IFN-g and TNF-a expression in pancreatic islets of female NOD mice is associated with ß cell destruction and overt diabetes.

Recent enterovirus infection in type 1 diabetes: Evidence with a novel IgM method

“…The cytokine TNF-a has been implicated in T1D and many rodent models show that induction of diabetes is associated with increased levels of TNF-a in the islets [Ventura-Oliveira et al, 2002].…”

Diacerhein downregulate proinflammatory cytokines expression and decrease the autoimmune diabetes frequency in nonobese diabetic (NOD) mice

“…In autoimmune DM-1, the accessory role of the proinflammatory cytokines IL-1β, IL12, IFN-γ and TNF-α in the disorganization of pancreatic islets has been established [11,17,36]. Recently, Narang et al [37] demonstrated the process by which the destruction of islet cells occurs.…”

“…Pancreatic islets were isolated from mice by stationary collagenase digestion of the pancreas, using previously described methods [11] with minor modification. Mice were anesthetized using intraperitoneal injection of 3% pentobarbital sodium (20 mg/kg).…”

“…Total cells from pancreatic islets were submitted to RNA extraction by a modified protocol of acid guanidium thiocyanate/phenol/ chloroform extraction [11,30,31]. The RNA was first reversetranscribed into cDNA (Superscript™ II -Life Sciences).…”

“…Correlation studies on cytokines expressed in islets and autoimmune diabetes in NOD mice have demonstrated that β cell destructive insulitis is associated with increased levels of proinflammatory cytokines (IL-1, TNF-α and IFN-γ) [3][4][5][6][7][8][9][10][11].…”