Effects of streptozotocin‐induced diabetes on neurogenic inflammation of gingivmucosal tissue in rat

Abstract

It has been suggested that the unmyelinated small diameter afferent nociceptive C-fibres are impaired in diabetes mellitus. We have recently demonstrated that these fibres are the prerequisite for neurogenic inflammation induced by mechanical or chemical irritations. These experiments were designed to characterize the neurogenic inflammatory responses of gingivomucosal tissue in the early phase of experimental induced diabetes mellitus in rat. Effect of dental ligature on the gingivomucosal (GM) vascular permeability was studied in control rats and in rats pretreated with streptozotocin at d 7 and 14 following streptozotocin administration. In separate groups of control and streptozotocin diabetic rats studies were also performed to investigate the effect of local capsaicin application on GM vascular permeability on d 14. Vascular permeability was assessed by means of Evans blue extravasation. The ligature placed around the mandibular left first molar caused a significant increase vascular permeability of GM tissue on the ipsilateral side on both d 7 and 14 after the ligation in control rats. In streptozotocin diabetic rats on d 7, there was also a significant elevation of Evans blue extravasation in the tissue tested on the ligature side. However, on d 14 the ligation failed to produce any changes in Evans blue extravasation on the ipsilateral side, i.e. no difference in GM vascular permeability could be recorded between the two sides in streptozotocin diabetic rats. Topical capsaicin administration produced significant Evans blue extravasation in GM tissue of control rats compared to that observed in diabetic rats on d 14 after streptozotocin treatment. Electron microscopic and light microscopic studies demonstrated fibre degeneration of the C neurones and less inflammatory cells in streptozotocin-induced diabetes in the gingivomucosal tissue. These findings appear to indicate that the inflammatory responses induced by mechanical (dental ligature) and/or chemical irritants (topical application of capsaicin) in the gingivomucosal tissue are altered in streptozotocin diabetic rats and this alteration is due to the diabetes-induced damage to the unmyelinated C fibres.

Neurogenic cutaneous vasodilatation and plasma extravasation in diabetic rats: effect of insulin and nerve growth factor

“…The effect of NGF on the neurogenic inflammatory response has not been, to our knowledge, previously investigated; although a reduced neurogenic response in the diabetic rat was first reported by Garcia‐Leme et al (1974) after stimulation of the saphenous nerve and confirmed in a related study (Gamse & Jansćo, 1985). A reduction of neurogenic inflammation has also been recently shown in the gingivomucosal tissue in the rat (Györfi et al , 1996). The conclusion from the study of Gamse & Jancsó (1985) was that the loss of the neurogenic response was a consequence of microvascular changes, rather than neuropeptide depletion.…”

Effect of Restraint Stress on the Progression of Experimental Periodontitis in Rats

“…There are several animal studies that have examined the relationship between stress and periodontal disease. 56,[63][64][65][66][67][68] In an early study, Gupta et al 64 observed that the alveolar crest of the interradicular area in a stressed hamster showed areas of osteoclastic activity and a reduction in remodeling activity. As mentioned above, Breivik et al 55 demonstrated that the periodontal degradation enhanced in Fischer 344 rats that responded to high HPA axis reactivity after subcutaneous corticosterone delivery.…”

Expression of Vascular Endothelial Growth Factor Has a Regulatory Role in Gingival Venules in Experimental Diabetes

“…Furthermore, it should be an important factor in the altered immune response that occurs in diabetes 33 . Other authors suggest that even the inflammatory responses induced by mechanical (dental ligature) and/or chemical irritants (topical application of capsaicin) in the gingivomucosal tissue are altered in streptozotocin‐diabetic rats, and this alteration at least partially results from the diabetes‐induced damage to the unmyelinated C fibers 34 . The regulation of the mucosal homeostasis seems even more complicated because the close anatomic associations suggest communication between nerve fibers and immune cells 35 …”

“…33 Other authors suggest that even the inflammatory responses induced by mechanical (dental ligature) and/or chemical irritants (topical application of capsaicin) in the gingivomucosal tissue are altered in streptozotocin-diabetic rats, and this alteration at least partially results from the diabetes-induced damage to the unmyelinated C fibers. 34 The regulation of the mucosal homeostasis seems even more complicated because the close anatomic associations suggest communication between nerve fibers and immune cells. 35 According to the results with experimental diabetes, it appears that not only does the number of mast cells increase significantly on the ground of diabetes in gingiva but the VEGFR2 expression of these mast cells rises as well.…”