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Selective damage to sensorimotor perivascular nerves in the mesenteric vessels of diabetic rats
A Belai1, P Milner, J Aberdeen
1Department of Anatomy and Developmental Biology, University College London, England, U.K.
Abstract:
The perivascular innervation of the superior mesenteric artery and vein was examined using immunohistochemical and immunoassay techniques in rats 8 weeks after induction of diabetes with streptozotocin (STZ). Increased density of innervation and fluorescence intensity was noted for substance P- and calcitonin gene-related peptide-immunoreactive nerves in the diabetic vessels. A slight increase in the density of vasoactive intestinal polypeptide-immunoreactive nerve fibers innervating the mesenteric artery was also noted. However, there was no change in the density of neuropeptide Y- and dopamine beta-hydroxylase-immunoreactive nerve fibers, although the fluorescence intensity of neuropeptide Y-immunoreactive nerve fibers was reduced in diabetic rat vessels. Immunoassays showed that the levels of substance P- and calcitonin gene-related peptide were increased > 10-fold in the diabetic mesenteric vein, while levels of neuropeptide Y and vasoactive intestinal polypeptide were unchanged. In summary, there is a marked increase in nerve fibers containing sensory neuropeptides in mesenteric vessels of STZ-induced diabetic rats, which, in view of the reported impaired sensorimotor function in these vessels, is likely to reflect a neuropathic change.
Insights
Diabetic rats show increased sensory nerve fibers in mesenteric vessels, suggesting a neuropathic change. This impacts vessel function, highlighting a key complication of diabetes.
Area of Science:
- Neuroscience
- Vascular Biology
- Endocrinology
Background:
- Diabetes mellitus is a complex metabolic disorder with significant vascular complications.
- Alterations in autonomic and sensory innervation of blood vessels are implicated in diabetic pathophysiology.
- The superior mesenteric artery and vein are crucial for gastrointestinal blood supply and are susceptible to diabetic damage.
Purpose of the Study:
- To investigate the changes in perivascular innervation of the superior mesenteric artery and vein in a rat model of diabetes.
- To quantify alterations in specific neuropeptides associated with sensory and sympathetic nerves.
- To correlate neurochemical changes with potential functional deficits in diabetic mesenteric vessels.
Main Methods:
- Streptozotocin (STZ)-induced diabetes model in rats.
- Immunohistochemical analysis for neuropeptide localization and density (Substance P, CGRP, NPY, VIP, DBH).
- Immunoassay techniques to quantify neuropeptide levels in mesenteric vessels.
Main Results:
- Increased density and fluorescence of Substance P and CGRP in diabetic mesenteric vessels.
- Slight increase in VIP-immunoreactive nerve fibers in the mesenteric artery.
- No change in density of NPY and DBH nerve fibers, but reduced NPY fluorescence intensity.
- Over 10-fold increase in Substance P and CGRP levels in diabetic mesenteric veins.
Conclusions:
- STZ-induced diabetes leads to a marked increase in sensory neuropeptide-containing nerve fibers in mesenteric vessels.
- These neurochemical alterations likely represent a neuropathic change in the mesenteric vasculature.
- The observed changes may contribute to the impaired sensorimotor function reported in diabetic mesenteric vessels.