Breathing pattern alteration from weanling to old age in male Sprague-Dawley rats

• Published in: Respiratory physiology & neurobiology 2025-01, Vol.331, p.104357, Article 104357
• Main Authors: Eslami-Behroozi, Mehdi, Shahsavar, Payam, Vali, Reyhaneh, Raoufy, Mohammad Reza
• Format: Article
• Language: English
• Subjects: Aging; Aging - physiology; Animals; Breathing pattern; Entropy; Male; Nonlinear dynamics; Rats; Rats, Sprague-Dawley; Respiration; Respiratory Mechanics - physiology
• ISSN: 1569-9048; 1878-1519; 1878-1519
• DOI: 10.1016/j.resp.2024.104357

Respiratory patterns were investigated in male Sprague-Dawley rats throughout their lifespan, from weanling (1 month) to old age (24 months), under natural conditions. Both inter-breath interval (IBI) and respiratory volume (RV) were examined. Sample entropy suggested increasing irregularity in IBI but decreasing irregularity in RV until 12 months. According to detrended fluctuation analysis, alpha exponent of the IBI showed a bimodal pattern around the value 0.7. From 1–15 months, the alpha exponent for RV generally decreased to the value 0.5, but it increased again as the animals neared the end of their lifespan. Cross-sample entropy revealed increasing synchronization between IBI and RV until 12 months, then plateauing. Many measures demonstrated a transition around 12 months, potentially reflecting maturation of respiratory control mechanisms. The findings characterize complex dynamics of respiratory patterns across the rat lifespan, providing a normative foundation to identify deviations indicative of dysfunction or disease. •Respiratory patterns in rats show complex changes from weanling to old age.•Many measures demonstrated a transition around 12 months.•The stabilization of complexity measures was observed after 12 months.