Blood flow distribution in embryonic common snapping turtles Chelydra serpentina (Reptilia; Chelonia) during acute hypoxia and α-adrenergic regulation

Developmental plasticity of the cardiovascular system in oviparous vertebrates: effects of chronic hypoxia and interactive stressors in the context of climate change

Animals at early life stages are generally more sensitive to environmental stress than adults. This is especially true of oviparous vertebrates that develop in variable environments with little or no parental care. These organisms regularly experience environmental fluctuations as part of their natural development, but climate change is increasing the frequency and intensity of these events. The developmental plasticity of oviparous vertebrates will therefore play a critical role in determining their future fitness and survival. In this Review, we discuss and compare the phenotypic consequences of chronic developmental hypoxia on the cardiovascular system of oviparous vertebrates. In particular, we focus on species-specific responses, critical windows, thresholds for responses and the interactive effects of other stressors, such as temperature and hypercapnia. Although important progress has been made, our Review identifies knowledge gaps that need to be addressed if we are to fully understand the impact of climate change on the developmental plasticity of the oviparous vertebrate cardiovascular system.

Developmental programming of sarcoplasmic reticulum function improves cardiac anoxia tolerance in turtles

Oxygen deprivation during embryonic development can permanently remodel the vertebrate heart, often causing cardiovascular abnormalities in adulthood. While this phenomenon is mostly damaging, recent evidence suggests developmental hypoxia produces stress-tolerant phenotypes in some ectothermic vertebrates. Embryonic common snapping turtles (Chelydra serpentina) subjected to chronic hypoxia display improved cardiac anoxia tolerance after hatching, which is associated with altered Ca2+ homeostasis in heart cells (cardiomyocytes). Here, we examined the possibility that changes in Ca2+ cycling, through the sarcoplasmic reticulum (SR), underlie the developmentally programmed cardiac phenotype of snapping turtles. We investigated this hypothesis by isolating cardiomyocytes from juvenile turtles that developed in either normoxia (21% O2; 'N21') or chronic hypoxia (10% O2; 'H10') and subjected the cells to anoxia/reoxygenation, in either the presence or absence of SR Ca2+-cycling inhibitors. We simultaneously measured cellular shortening, intracellular Ca2+ concentration ([Ca2+]i), and intracellular pH (pHi). Under normoxic conditions, N21 and H10 cardiomyocytes shortened equally, but H10 Ca2+ transients (Δ[Ca2+]i) were twofold smaller than those of N21 cells, and SR inhibition only decreased N21 shortening and Δ[Ca2+]i. Anoxia subsequently depressed shortening, Δ[Ca2+]i and pHi in control N21 and H10 cardiomyocytes, yet H10 shortening and Δ[Ca2+]i recovered to pre-anoxic levels, partly due to enhanced myofilament Ca2+ sensitivity. SR blockade abolished the recovery of anoxic H10 cardiomyocytes and potentiated decreases in shortening, Δ[Ca2+]i and pHi. Our novel results provide the first evidence of developmental programming of SR function and demonstrate that developmental hypoxia confers a long-lasting, superior anoxia-tolerant cardiac phenotype in snapping turtles, by modifying SR function and enhancing myofilament Ca2+ sensitivity.

Effects of Developmental Hypoxia on the Vertebrate Cardiovascular System

Developmental hypoxia has profound and persistent effects on the vertebrate cardiovascular system, but the nature, magnitude, and long-term outcome of the hypoxic consequences are species specific. Here we aim to identify common and novel cardiovascular responses among vertebrates that encounter developmental hypoxia, and we discuss the possible medical and ecological implications.

Obesity prolongs induction times in reptiles

Obesity is common in captive reptiles, and reptiles are increasingly popular as companion animals and in physiological research. Obesity may present a challenge during surgical procedures using inhalation anaesthesia, as the long induction time due to the low reptilian metabolism may increase anaesthetic accumulation in the adipose tissues. This study investigated the impact of obesity on induction and recovery times from inhaled anaesthesia. The temporal change in the partial pressure of isoflurane in different tissues was predicted using a multi-compartment model. Furthermore, as right-to-left shunting can delay anaesthetic uptake and washout, we included an assessment of the combination of cardiac shunting and obesity. The model predictions indicate a clear increase in time to reach 90% equilibration of administered anaesthetic in the brain (T₉₀) of obese non-shunting (lean 47 min, obese >100 min) and shunting (lean 81 min, obese >100 min) reptiles. The combination of obesity and shunting doubled the time to acquisition of mean anaesthetic concentration (a measure used to plan anaesthesia) from 8 min to 19 min. Adipose blood flow highly affected whether the body type had an impact on induction time, with low adipose blood flow abolishing the effect of body type. As T₉₀ was never reached within 100 min with both the obese reptiles, it was not possible to conclude on the effect of obesity on recovery times within this study. Care should therefore be taken when anaesthetising obese reptiles for surgical purposes, to ensure adequate anaesthetic depth is attained, and recovery monitored closely.

Efficacy of phentolamine combined with ambroxol aerosol inhalation in the treatment of pediatric severe pneumonia and its effect on serum IL-10 and CRP levels

BACKGROUND

The aim of the present study was to determine the therapeutic effect of phentolamine combined with Ambroxol aerosol inhalation on pediatric severe pneumonia and its effect on serum interleukin-10 (IL-10) and C-reactive protein (CRP) levels.

METHODS

Eighty-five children with severe pneumonia treated in our hospital from November 2019 to November 2020 were selected as the research participants, and were divided into the routine group (n=41) and treatment group (n=44) according to odd and even admission numbers, respectively. Children in the first group received routine treatment, namely symptomatic treatment such as cough relief (e.g., expectorant) and defervescence, while those in the second group received phentolamine combined with Ambroxol aerosol inhalation. Clinical indexes of both groups before and after treatment were analyzed to determine the therapeutic effect of different treatment methods and serum IL-10 and CRP level changes.

RESULTS

There was no significant difference in general clinical data between the 2 groups (P>0.05). The duration of cough, fever, abnormal lung sound and lung shadow, and hospitalization time in the treatment group was significantly shorter than those in the routine group (P<0.001). The total clinical effective rate in the treatment group was significantly higher than that in the routine group (P<0.05). Forced vital capacity and peak expiratory flow rate levels were higher in both groups after treatment (P<0.05), and these were higher in the treatment group compared with the routine group after treatment (P<0.05). Serum IL-10 and CRP levels at T1 (2 days after treatment), T2 (5 days after treatment), and T3 (7 days after treatment) in the treatment group were significantly lower than those in the routine group (P<0.001). The total incidence of adverse reactions in the treatment group was significantly lower than that in the routine group (P<0.05).

CONCLUSIONS

Phentolamine combined with Ambroxol aerosol inhalation can significantly improve the clinical symptoms of children with severe pneumonia, reduce the body's inflammatory response, and improve lung function safely.