Objective: To study the value of measuring electrical discharge of external oblique in assessment of young rat model of visceral hypersensitivity.
Methods: Eight-day-old neonatal Sprague-Dawley rats were randomly assigned to two groups: an experimental group and a control group (n=16 each). Rats in the experimental group were subjected to mechanical colorectal irritation daily for 7 consecutive days, while the rats in the control group did not received colorectal irritation treatment. On the 6th week of their lives, the spike amplitude of external oblique were measured to evaluate the bowel sensitivity.
Results: When the colorectal distention (CRD) pressure was 30 and 45 mmHg, the 95% confidence interval of the spike amplitude in the experimental group was significantly higher than that in the control group (P<0.01). When the CRD pressure were 60 and 75 mmHg, the 95% confidence interval of the spike amplitude in female rats was significantly higher than that in males (P<0.05).
Conclusions: The electrical discharge of external oblique confirmed that chronic colorectal irritation in neonatal rats can result in a chronic visceral hypersensitivity in the juvenile stage, with gender differences. Electrophysiological assessment is a quantitative test, and can objectively reflect visceral sensibility of pain.