| Meriones meridianus is one of the most common rodent species in the western desert and semi desert area and it is a special type of tolerance for a dry climate. Because of the lack of water intake, the kidney and liver tissues may induce a series of adaptive response by the water shortage in the body. As an important component of energy conversion, the enzyme active changes of the mitochondrial respiratory chain complex reflect cell energy metabolism level under stress condition of the tissues. Kidney and liver are not only an important tissue of urinary and digestive system, but also an important part of the body system, which have a function maintaining fluid balance and homeostasis in the body. Kidney and liver are sensitive to stress response with body water deficiency and they are also good materials in the study of water stress responses in the animal body.In this paper, the Meriones meridianus as material, we selected healthy and mature animals, which were divided into food water deprivation group of 0, 3, 6, 9 days with 6 animals in each group. The control group(0d) was fed with carrots, vegetables and the food water deprivation group was fed with corn, wheat seeds etc. The serum, kidney and liver tissue was taken after completing the experiment and mitochondria of tissues was extracted respectively. The activity of mitochondrial respireatory chain enzyme complexes I(C I, N-ADH dehydrogenase), II(C II, succinate dehydrogenase), III(C III, cytochrome Creductase), IV(C IV, cytochrome C oxidase), superoxide dismutase(SOD) and content of lipid peroxidation product malondialdehyde(MDA) in kidney and liver tissue was tested by using spectrophotometric method. The expression change of AQP1/2, HIF-1α, Bax and c-fos protein of kidney and liver tissue in different time food water restriction was detect by using immunohistochemical method. SOD activity and MDA content in serum was measured.Result:1. The animal body weight and food intake were gradually reduced by water restriction. The activity of mitochondrial respiratory chain of four kinds of complex in kidney and liver tissue increased obviously(P<0.05, P<0.01) while 3 day is an important stage of adaptive response at the food and water restriction. The rise range of respiratory chain complex activity was the largest at 3d in water restriction and the activity decreased for 9 d but still higher than the control. Food and water restrictions induced active rise of mitochondrial respiratory chain complex enzyme in kidney and liver tissues maybe related to increase of renal reabsorption to water and liver metabolism.2. The SOD activity of kidney mitochondria was increased differently and the content of mitochondrial MDA increased significantly in kidney and liver tissue at the food water restriction. The activity of SOD and the content of MDA in serum also increased under the food water restriction. The antioxidase can effectively remove active oxygen free radical at the beginning, but the antioxidase activity was inhibited by prolong water limit. The levels of free radical elevated induced by water restriction for long time may produce negative affect on the maintenance activity of metabolic enzyme.3. The expression of AQP-2 in kidney tissue were raised by food water restriction, and the upregulation of expression of AQP-2 was biggest(P<0.05) in 3d, the expression of AQP1 remained elevated(P<0.05 or P<0.01) during food water restriction. The increaseing of AQP1 and AQP2 expression can increase the permeability of cell membrane. The high expression of AQP1 in kideny tissue show the kidney of Meriones meridianus has strong water reabsorption function, and the high expression of AQP2 in renal tissues was related to the strong urine concentrating ability of Meriones meridianus.4. The proteins expression of HIF-1α, c-fos, Bax in kidney tissue increased significantly(P<0.05 or P<0.01) with the extension time of food water restriction extension, and the proteins expression of HIF-1α, c-fos, Bax rose significantly and the range was maximum(P<0.05) during water limitation 0-3d in liver tissue, but fall during 6-9d water limitation. However, the expression of c-fos in 9d was lower than the control(1.16%) under food water restriction. There was a positive correlation between the expression of HIF-1α and Bax and the expression was still higher than the control in the 9d. HIF-1α may be involved in regulating food water restriction in the apoptotic response. The water shortage caused by food water limitation is a slow process. The water inadequate intake for a long time is one of the factors of the osmotic pressure of plasma rise and blood volume reduction ect, while other regulatory factors such as arginine vasopressin may also be take part in the change of active substances above.Conclusion:1. The activity of mitochondrial respiratory chain complex enzyme in kidney and liver tissues rose during food water restrictions.2. The activity of SOD and the content of MDA in kidney and liver tissue and serum increased significantly under water food restriction.3. The protein expression of AQP1/2 in kidney tissue increased in different degree during food water restriction.4. The protein expression of HIF-1α, c-fos and Bax in liver tissue increased in different degree under food water restriction.Therefore, 0-3d under food water restriction is an important stage for the adaptation of related metabolism changes in tissue of body. The level of free radicals rose and the changes of the relevant regulatory factor induced by a long time water limitation may have adverse effects on maintenance metabolic enzyme activity and normal function of the liver and kidney tissues. |
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