title: Diabetic autonomic neuropathy: evidence for apoptosis in situ in the rat.
abstract: We examined the hypothesis that activation of the apoptosis cascade occurs relatively early in diabetes mellitus affecting three distinct neuronal populations that are involved in regulating gut function: (i) dorsal root ganglion (DRG), (ii) vagus nodose ganglion and (iii) colon myenteric plexus. A validated streptozotocin-induced diabetic rat model and age-matched healthy controls were studied. After 4-8 weeks of diabetes the animals were anaesthetized, fixed in situ and the relevant tissues removed. After 1 month of diabetes some animals were treated with insulin for 2 weeks to restore euglycaemia. Apoptosis was measured using immunohistochemical detection of activated caspase-3 and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL)-positive cells in adjacent sections in neurones (PGP 9.5-positive cells). The level of apoptosis was confirmed using double-label assessment of caspase-3 and TUNEL in DRG preparations. Caspase-3 immunoreactive neurones demonstrated a range in staining intensity. When all grades of staining were included, 6-8% of the DRG, nodose ganglia and myenteric neurones were immunoreactive in the preparations from diabetic rats compared with 0.2-0.5% in controls. Neurones staining positive for both caspase-3 and TUNEL accounted for 1-2% of the total neuronal population in all three preparations in diabetic rats compared with 0.1-0.2% in controls (P < 0.05). Insulin treatment reversed the percentage of TUNEL-positive neurones in diabetic rats to control levels. Activation of the apoptosis cascade occurs relatively early in diabetic autonomic neuropathy and may contribute to the pathophysiology of this disorder.
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: C
authors.initials: C
authors.lastname: Guo
authors.forename: A
authors.initials: A
authors.lastname: Quobatari
authors.forename: Y
authors.initials: Y
authors.lastname: Shangguan
authors.forename: S
authors.initials: S
authors.lastname: Hong
authors.forename: J W
authors.initials: JW
authors.lastname: Wiley
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000473:pathology*; D003929:Diabetic Neuropathies / Q000473:pathology*; D005725:Ganglia, Autonomic / Q000473:pathology; D005727:Ganglia, Spinal / Q000473:pathology; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008297:Male; D009197:Myenteric Plexus / Q000473:pathology; D009474:Neurons / Q000378:metabolism / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases