The objective of this study is to combine troponin and indicators of cardiac acoustics for synthetically evaluating cardiac fatigue of rabbits, analyzing exercise-induced cardiac fatigue (EICF) and exercise-induced cardiac damage (EICD). New Zealand white rabbits were used to conduct a multi-step swimming experiments with load, reaching an exhaustive state for evaluating if the amplitude ratio of the first to second heart sound (S1/S2) and heart rate (HR) during the exhaustive exercise would decrease or not and if they would be recovered 24-48 h after exhaustive exercise. The experimental end point was to complete 3 times of exhaustions or death from exhaustion. Circulating troponin I (cTnI) were detected from all of the experimental rabbits at rest [(0. 02±0. 01) ng/mL], which, in general, indicated that there existed a physiological release of troponin. After the first exhaustive swim, cTnI of the rabbits increased. However, with 24-hour rest, S1/S2, HR, and cTnI of the tested rabbits all returned toward baseline levels, which meant that the experimental rabbits experienced a cardiac fatigue process. After repeated exhaustion, overloading phenomena were observed, which led to death in 3 out of 11 rabbits, indicating their cardiac damage; the troponin elevation under this condition could be interpreted by pathological release. Evaluation of myocardial damage can not be based on the troponin levels alone, but can only be based on a comprehensive analysis.
Animals ; Fatigue ; Heart ; physiopathology ; Heart Rate ; Myocardium ; pathology ; Rabbits ; Swimming ; Troponin I ; blood

This paper presents a preliminary study of rabbit experiment modality incorporating a new indicator for evaluating cardiac function changes, providing a basis for subsequent study of cardiac fatigue. Using only biochemical indicators, such as troponins, is difficult to make a distinction between exercise-induced cardiac fatigue (EICF) and exercise-induced cardiac damage (EICD). Therefore, some new indicators are needed to evaluate cardiac fatigue synthetically. In our study, we used New Zealand white rabbits to conduct a multi-step swimming experiments with load. We made the rabbits reach an exhaustive state to evaluate whether the amplitude ratio of the first to second heart sound (S1/S2) and heart rate (HR) during the exhaustive exercise would be decreased and whether they would be able to recover after the exhaustive exercise for 24 hours. During the first phase of swimming, S1/S2 and HR were increased, and then decreased at exhaustive state. They were recovered after the exhaustive exercise for 24 hours. Overloading led to deaths of three rabbis, and new phenomena from overloading and related to this kind of death were observed. The experiments proved that Multi-steps swimming experiments with loads by using New Zealand white rabbit is useful for studying cardiac fatigue and premonition of sudden cardiac death.
Animals ; Cardiovascular Physiological Phenomena ; Death, Sudden, Cardiac ; Female ; Heart ; physiology ; Heart Rate ; physiology ; Male ; Muscle Fatigue ; physiology ; Myocardial Contraction ; physiology ; Myocardium ; chemistry ; Physical Endurance ; physiology ; Rabbits ; Stress, Physiological ; physiology ; Swimming

Ulcerative colitis(UC)is a chronic non-specific inflammatory disease of the intestine.With the application of biological agents,more and more UC patients have achieved endoscopic healing,but about one-third of UC patients achieving endoscopic healing still have histological activity,and this sustained histological activity may be associated with disease recurrence.Therefore,histological remission of UC has received increasing attention in clinical practice.In 2020,European Crohn's and Colitis Organization(ECCO)proposed histological remission as an important therapeutic target for UC.In 2021,the International Organization for the Study of Inflammatory Bowel Disease(IOIBD)in its latest program on standard treatment pointed out that histological remission will be used as a measure of deep remission.This article reviewed the progress of research on clinical application of histological remission assessment in UC.

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular event that often is followed by permanent brain impairments. It is necessary to explore the pathogenesis of secondary pathological damages in order to find effective interventions for improving the prognosis of SAH. Blockage of brain lymphatic drainage has been shown to worsen cerebral ischemia and edema after acute SAH. However, whether or not there is persistent dysfunction of cerebral lymphatic drainage following SAH remains unclear. In this study, autologous blood was injected into the cisterna magna of mice to establish SAH model. One week after surgery, SAH mice showed decreases in fluorescent tracer drainage to the deep cervical lymph nodes (dcLNs) and influx into the brain parenchyma after injection into the cisterna magna. Moreover, SAH impaired polarization of astrocyte aquaporin-4 (AQP4) that is a functional marker of glymphatic clearance and resulted in accumulations of Tau proteins as well as CD3⁺, CD4⁺, and CD8⁺ cells in the brain. In addition, pathological changes, including microvascular spasm, activation of glial cells, neuroinflammation, and neuronal apoptosis were observed in the hippocampus of SAH mice. Present results demonstrate persistent malfunction of glymphatic and meningeal lymphatic drainage and related neuropathological damages after SAH. Targeting improvement of brain lymphatic clearance potentially serves as a new strategy for the treatment of SAH.
Animals ; Apoptosis ; Aquaporin 4 ; Astrocytes ; Brain ; Brain Ischemia ; Cisterna Magna ; Drainage ; Edema ; Hippocampus ; Lymph Nodes ; Mice ; Neuroglia ; Neurons ; Prognosis ; Spasm ; Subarachnoid Hemorrhage ; tau Proteins