renatal hypoxia affects scaling of blood pressure and arterial wall mechanics in the common snapping turtle, Chelydra serpentin

Author(s)

Filogonio, Renato ^[1] ; Dubansky, Benjamin D. ^[2] ; Dubansky, Brooke H. ^[3] ; Leite, Cleo A. C. ^[1] ; Crossley, II, Dane A.

Affiliation

^[1] Univ Fed Sao Carlos, Dept Physiol Sci, BR-13565905 Sao Carlos, SP - Brazil

^[2] II, Univ North Texas, Dev Integrat Biol Cluster, Dept Biol Sci, Denton, TX 76203 - USA

^[3] Louisiana State Univ, Sch Vet Med, Dept Comparat Biomed Sci, Baton Rouge, LA 70803 - USA

• Document type: Journal article
• Source: COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY; v. 260, OCT 2021.
• Web of Science Citations: 0

Abstract

In reptiles, exposure to hypoxia during embryonic development affects several cardiovascular parameters. These modifications may impose different mechanical stress to the arterial system, and we speculated that the arterial wall of major outflow vessels would be modified accordingly. Since non-crocodilian reptiles possess a partially divided ventricle, ensuing similar systemic and pulmonary systolic pressures, we investigated how morphological and mechanical properties of segments from the left aortic arch (LAo) and the proximal and distal segments of the left pulmonary artery (LPAp and LPAd, respectively) change as body mass (Mb) increases. Eggs from common snapping turtles, Chelydra serpentina, were incubated under normoxia (21% O-2; N21) or hypoxia (10% O-2; H10), hatched and maintained in normoxia thereafter. Turtles (0.11-6.85 kg) were cannulated to measure arterial pressures, and an injection of adrenaline was used to increase pressures. Portions of the LAo, LPAp and LPAd were fixed under physiological hydrostatic pressures for histology and mechanical assessment. Arterial pressures increased with M-b for N21 but not for H10. Although mechanical and functional characteristics from the LPAp and LPAd were similar between N21 and H10, wall thickness from LAo did not change with M-b in the H10 group, thus wall stress increased in larger turtles. This indicates that larger H10 turtles probably experience an elevated probability of arterial wall rupture without concomitant changes in the cardiovascular system to prevent it. Finally, collagen content of the LPAp and LAo was smaller than in LPAd, suggesting a more distensible arterial wall could attenuate higher pressures from larger turtles. (AU)

• FAPESP's process: 18/05035-0 - Cardiovascular regulation in Squamates: validation of the decerebrated rattlesnake model for studies on regulatory processes of the cardiovascular system
• Grantee: Cléo Alcantara Costa Leite
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/20158-6 - Cardiovascular morpho-functional adaptations for allometric scaling of arterial blood pressures to body mass in reptiles
• Grantee: Renato Filogonio
• Support Opportunities: Scholarships in Brazil - Post-Doctoral