Intestinal neurotransmitters and PARS activation in streptozotocin induced diabetic rats

Background and aims: Intrinsic and extrinsic intestinal innervation can be altered during diabetes. The purpose of our study was to compare the localization and density of different neurotransmitter containing nerve fibres in diabetic and control rats.

Material and methods: Vasoactive intestinal polypeptide (VIP), substance P (SP), neuropeptide Y (NPY), tyrosine hydroxylase (TH), somatostatin (SOM), nitric oxide synthase (NOS) immunoreactive (IR) nerve fibres and poly (ADP-ribose) synthetase (PARS) IR immunocompetent cells were studied by immunohistochemistry in the intestine of Streptozotocin-induced diabetic rats.

Results: VIP IR nerves were found mostly in the smooth muscle layers and in the intramural nerve plexuses; NPY and TH IR nerves were seen mostly in the periarterial networks of control rats. In the diabetic intestine the quantitative analysis revealed that the density of SP, VIP and SOM IR nerve fibres was increased. These immunolabelled nerves were observed in close vicinity of immunocompetent cells. Pars Ir connective tissue cells appeared in significantly higher number in the diabetic (inflamed) specimens.

Conclusion: The alteration of the neurotransmitter balance and PARS activation seen in diabetes can cause various inflammatory responses and might be one of the key factors in the pathogenesis of intestinal inflammation and motility disorders of diabetic enteropathy.