Experimental diabetes and inflammatory reactions in the rat

Abstract

The colloidal carbon technique used in rats to study vascular permeability changes shows two main pictures: (1) Predominant capillary accumulation of carbon, observed in pulmonary edemas produced by many different methods.(2) Predominant venular and arteriolar labeling, as seen in alpha-naphtylthioureainduced pulmonary edema. The ultrastructural alterations of the lung blood vessels in acute immunological pulmonary edemas of rats, mice and guinea-pigs are characterized by vacuolization, swelling and sloughing of the endothelium and epithelium, by occlusion of small vessels by platelet thrombi, by opening of the endothelial and epithelial junctions and by interstitial edema. Separation of the endothelium from the epithelium, forming channels, may be observed in the alveolar vessels, suggesting drainage of fluids through these channels from the alveolar level to larger interstitial spaces.Because of biochemical importance of the neurotransmitters at the sinapses, the study of the enzymatic systems which interfere with their metabolism and function became relevant and two research groups have been working in this field, with the following results: (1) At the cholinergic level it could be observed (C. Baratti and J. Mifio) that eserine and oxotremorine, increasing acetylcholine content of the dorsal hippocampus of the rat, acts differently on the cholinacetilase (ChAc) and cholinesterase (ChE) activity eserine: + ChE; = ChAc, oxotremorine: = ChE; + ChAc. This latter effect could be due to the intraneuronal increase of acetylcholine. Eserine facilitates and oxotremorine does not modify discrimination unpublished data. (2) At the serotoninergic level, in mesencephalon, pons and medulla oblongata rat (J. A. Izquierdo, E. Chemerinski and M. Billiet) it was found that pregnenolone medroxy-progesterone and DOCA by inducing a liver enzyme with pyrrol oxygenase activity, decreased significantly serotonin content in those brain regions; 5-Hydroxyindoleacetic content is not modified.Swelling induced in the rat's paw by dextran, carrageenin and cellulose-sulfate is markedly reduced in alloxan-diabetic rats or in rats submitted to sub-total pancreatectomy. Render-ing diabetic animals normoglycemic through fasting, the swelling inhibition still persisted. Insulin reversed such inhibition. Diabetic animals presented decreased responses to intradermally

Kinin B1 receptors: key G‐protein‐coupled receptors and their role in inflammatory and painful processes

“…The progress of the diabetes and the constant fluctuation of glucose levels are associated with changes in vascular structure (mainly related to the endothelium) and the production of vasoactive substances. In this context, the kinin system has often been implicated in the pathophysiology of diabetes ( Garcia Leme et al ., 1973 ; Couture et al ., 2001 ). Moreover, the extent to which diabetes may influence the modulation of B 1 receptors has been the matter of several recent publications.…”

Inhibition of leukocyte chemotaxis by serum factor in diabetes mellitus: Selective depression of cell responses mediated by complement-derived chemoattractants

“…In addition, there is a recognized group of rare infections where the incidence is definitely increased in diabetes mellitus and which may be confined almost entirely to the diabetic patient [2]. At least in part this condition might result from the impaired capacity to mount an inflammatory reaction [4][5][6], from functional changes in the behavior of microvessels [7], and from decreased responsiveness of the endothelial cell to endogenous vasoactive agents [8][9][10]. Furthermore, investigations on chemotaxis of polymorphonuclear leukocytes from diabetic subjects show that, while there are a few negative results, defective responses of the cells in the presence of a chemoattractant gradient can occur.…”

Mast cell changes in experimental diabetes: focus on attenuation of allergic events

“…Administration of alloxan to different animals produces, via necrosis of the islets, several features common to those observed in human diabetes (Lukens 1948, Gaulton et al 1985, Quan et al 2001. There is some evidence that diabetics present a deficiency in mounting an inflammatory response, probably associated with severe reduction in insulin secretion rather than increased blood glucose levels (Garcia Leme et al 1973, Garcia Leme & Farsky 1993. This is still a controversial point as other investigators have suggested a direct correlation between hyperglycemia and the incidence of infection in diabetic patients (Rayfield et al 1982).…”