Archived Issues

We congratulate you on acceptance of your manuscript.

Browse by Year

Neuroprotection in Temperature and Oxygen Stressed Turtles

October 17, 2019

AbstractThis study is designed to detect the expression levels of heat shock protein 72 in the forebrain, midbrain, hindbrain, and ventricles of T. scripta, when subjected to anoxia and warm and cold temperatures for various periods of time. Previous studies have shown that HSP72 is induced early in anoxia, increasing for 8 hours but then falling to normoxic levels by 12 hours of anoxia showing that HSP72 may play a key role in the initial transition to the anoxic state (Milton and Prentice 2007).  This study examined the brain in sections, rather than the previous whole brain.

Keywords – Neuroprotection, temperature, oxygen stress, turtles, and Trachemys scripta


Introduction: The freshwater turtle, Trachemys scripta, has a unique ability to survive without oxygen for prolonged periods of time.  Unlike a vast majority of vertebrates that die after a few minutes of being deprived of molecular oxygen (anoxia), anoxia- tolerant vertebrates can survive from hours to weeks (Stecyk et al., 2007).  Anoxia followed by reoxygenation produces a rapid transient increase in reactive oxygen species (ROS) that destroys cells and its contents (Hashimoto et al. 2003). The mammalian brain is susceptible to ROS; however T. scripta may employ protective mechanisms to survive anoxia, thus preventing ROS damage.  Not only is brain function protected, but heart function is, too. One protective mechanism is the over expression of heat shock proteins (HSPs).  HSPs are overexpressed when cells are stressed, acting as a molecular chaperone. The brains and hearts of T. scripta were exposed to anoxia at 21°C, normoxia at 5°C, and anoxia at 5°C, with normoxia at 21°C as the control group. Exposure times ranged from 1.5 hours to 2 weeks. Each sample, weighing at least 200mg, was homogenized and the proteins were extracted.  Protein assays were performed on the extracts to determine the respective concentrations. Western blots were done to detect the presence of heat shock protein 72. Results are expressed as ±SD.


References

[1] Hashimoto, T., Yonetani, M., Nakamura, H. 2003. Selective brain hypothermia protects against hypoxic- ischemic injury in newborn rats by reducing hydroxyl radical production. Kobe J. Med. Sci. 49(4), 83-91. 
[2] Milton, S.L., Prentice, H.M. 2007. Beyond anoxia: The physiology of the metabolic downregulation and recovery in the anoxia- tolerant turtle.  Comp. Biochem. Physiol. A 147, 277- 290.
Stecyk, J.A.W., Stensløkken, K.-O., Nilsson, G.E., Farrell, A.P. 2007. 
[3] Adenosine does not save the heart of anoxia- tolerant vertebrates 
during prolonged oxygen deprivation. Comp. Biochem. Physiol. A  
147, 961- 973.