| The Fifth Assessment Report of the Intergovernmental Panel on Climate Change indicated that the updated 100-year linear trend (1906 to 2005) is 0.74℃, and the global air temperature is predicted to to reach 1.8-4.0℃ above the current level by 2100. Birds are an important group in terrestrial ecosystems, which should be paid more attention in global climate warming. Birds living in the high latitude and cold regions have already adapted for cold environment in evolution, but it is still not clear if climate warming will influent their physiological processes even their survival or not as a kind of chronic stress. This research has preliminarilly studied the mechanism of cellar antiapoptosis and physiological adaptability of short-toed lakes in response to climate warming via a series of environmental stress test in lab.Heat shock protein (HSP) is a kind of intrinsic protective protein which is indispensable under physiological state, and its expression increased in the stress state (especially in heat stress). Previous studies had confirmed that HSP protein could significantly inhibit cell apoptosis by reducing the release of Pro apoptotic protein Smac. Bcl-2, as a kind of antiapoptotic protein, can inhibit cell apoptosis stimulated by SMAC release from mitochondria. While caspase3 is a key enzyme in the process of cell apoptosis,In addition,temperature rise can also be an environmental stimulation affecting oxidative stress and immune function in the level of cell. The purpose of this study was to characterize the expression of apoptosis (caspase 3, Bcl-2)、survival (HSP 60、90) proteins、antioxidant enzymes SOD、CAT、GSH-px and Immunoglobulin(IgA, IgG, IgM) protein in blood cells of short-toed lakes after heat stress. We can draw several conclusions:1.Effects of climate warming on apoptosiss factorsIn order to study cellular tolerance of birds in response to higher temperature under climate warming in spring.First of all,we compared the apoptosis related protein of 2014(high temperature year) and 2015(low temperature year) in short-toed lake blood cell. Results obtained by Western blotting show that:Although Bcl-2 and Caspase3 expression fluctuated obviously due to daily average temperature change, on April 13,2014, the day had a significant rise in temperature, caspase3 expression was still up-regulated (p<0.01),Bd-2 expression was decreased (p<0.01).And the results show that HSP60、90 was significantly increased in 2014 than in 2015(p<0.01). To further investigate the effect of temperature on cell apoptosis protein, this study set two group of chronic temperature stress experiment, one high temperature group (21℃) and one low temperature group(16℃,simulating the wild temperature), results as follows:(7)The expression of HSP60、90 proteins of heat stress group (21℃) was significantly higher than that in the cold group (16℃) (p<0.01);(2) the expression of caspase3 of heat stress group(21℃) was significantly increased within first four days(p<0.05); whereas by contrast, the expression of Bcl-2 of 21℃ group was significantly decreased within first four days. It means high temperature can induce upregulate of caspase3 expression, which causes cell apoptosis of birds. (5) With the increasing of HSPs expression in a period time. Caspase3 expression decreased, bcl-2 expression was up-regulated, indicating that apoptosis induced by the heat stress can be control significantly. In a word, HSPs have an obvious protective effect against cell apoptosis induced by heat stress, which related to the activation of anti apoptotic signal pathway.2.The effect of heat stress on antioxidant enzymeAfter heat stress(21℃), changes of Superoxide Dismutase(SOD)、 Catalase (CAT) and Glutathione peroxidase (GSH-Px) contents in short-toed lake long term cultured in lab were studied and compared with those in cold group(16℃). Results showed that:in the heat stress group(21℃), antioxidant enzyme activities significantly decreased. In theory, when birds subjected to acute heat stress, ROS are generated in the plasma then induce the increase of antioxidant enzymes. However enzymatic activities decreased over time, it indicated that accumution ofROS contributed to the accumulation of oxidative damageto cellular constituents. In consequence, HSPs expression is still maintained at a higher level, which has an important role in enhancing the body’s resistance.3.The effect of heat stress on Immunoglobulin of short-toed lakesAfter heat stress, change of IgA、IgG、IgM contents in short-toed lakes long-term cultured in heat stress group (21℃) were studied and compared with those in cold group(16℃).Results showed that:after heat stress,IgA、IgG、IgM expression were extremely significantly decreased, which illustrates the thermal stress of short toed lark immune greatly affects the performance, and cause the destruction of the balance between oxidation and antioxidation system, heat stress can induce oxidative damage of immune organs and cells. |
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