The impaired activity of sensory afferent nerves in diabetes mellitus of rats in acute myocardial ischemia and reperfusion / 临床麻醉学杂志

ABSTRACT

Objective The aim of the study was to investigate the diabetic neuro-degeneration and its changes in neuroreaction to myocardial ischemia and reperfusion,by evaluation of the altera-tion of noxious thermal threshold and expression of substance P (SP),calcitonin gene related peptide (CGRP)in dorsal root ganglia in upper thoracic segments (T1-5 )in diabetic rats.Methods Thirty two male Sprague-Dawley rats,weighing 180-200g,were randomly divided into control group (group C)and diabetic group (group DM),1 6 rats in each group.rats in DM group were fed with high sug-ar-fat diet for 14 weeks and were given streptozotocin (STZ,35 mg/mg,i.p.)at the end of the 4 th week,to set up diabetes experimental model.The animals in control group were fed with standard la-boratory diet.Tail flick latency to thermal stimulation was measured weekly.At the end of 10 weeks after administration of STZ,diabetic rats (and rats in control group)were further divided into myo-cardial ischemia-reperfusion group (group IR)and sham operation group (group Sham).The left an-terior descending branch of coronary artery was occluded for 30 min followed by reperfusion for 120 min,establishing myocardial ischemia-reperfusion.The histological immunofluorescence assay and Enzyme-linked immunosorbent assay (ELISA)were carried out to evaluate the changes of the expres-sions of CGRP and SP in the dorsal root ganglia.Results The tail flick latency was significantly in-creased in group DM,compared to the group C (P < 0.01).The immunoreactive materials for CGRP and SP in the sensory neurons in dorsal root ganglia of upper thoracic segments (T1-5 )were markedly declined in group DM (P <0.01 or P < 0.05).Furthermore,levels of SP and CGRP were signifi-cantly lower in the DRG of the group IR after myocardial ischemia-reperfusion,compared to that in the group sham (P <0.01).Conclusion Diabetes causes sensory denervation and obvious reduction of expression of SP and CGRP in the sensory neuron innervating heart during myocardial ischemia-reper-fusion,indicating impairment of adaptive reactivity of neuro-endocrine function of cardiac sensory nerves.