Necrotizing enterocolitis attenuates developmental heart rate variability increases in newborn rats

Area of Science:

• Gastroenterology
• Neonatal Research
• Physiology

Background:

• Decreased high-frequency heart rate variability (HF-HRV), indicating reduced vagal tone, may predict necrotizing enterocolitis (NEC) in neonates.
• This study investigates the impact of NEC induction and vagotomy on HF-HRV and NEC severity in rat pups.

Purpose of the Study:

• To determine if NEC induction in rat pups decreases HF-HRV.
• To assess if subdiaphragmatic vagotomy exacerbates NEC severity, inflammatory markers, and myenteric phenotype.

Main Methods:

• Newborn rats were subjected to cold stress and hypoxia to induce NEC, with or without unilateral subdiaphragmatic vagotomy.
• Heart rate variability (HRV) was measured, and pups were analyzed for gastrointestinal histology, cytokine levels, and myenteric plexus changes.

Main Results:

• NEC induction led to histological signs of NEC, which were more severe with vagotomy.
• Developmental increases in HRV (RMSSD, HF) were reduced in NEC pups, especially after vagotomy.
• Vagotomized NEC rats showed increased pro-inflammatory cytokines (IL-1β, IL-6) and altered myenteric nitric oxide synthase.

Conclusions:

• NEC induction in rodents attenuates developmental increases in HF-HRV.
• Subdiaphragmatic vagotomy worsens NEC histological severity and increases inflammation.
• The vagus nerve appears to play a role in NEC pathology development.