| Objective: Acute renal failure (ARF) is a common clinical syndrome resulting from various pathophysiological states. There are inappropriate changes of renal hemodynamics that renal blood flow reduce 50%,and glomerular function reduce rapid at the process of ARF. Among the factors, an ischemic insult has been the leading cause of ARF in humans. The inappropriate release of vasoactive substances, the disbalance conditioms of vasoconstrictors and vasodilatators, play a important role for pathogenesis of ARF. Arginine Vasopressin(AVP) can cause vasoconstract in vivo, which contributes to regulate the hemodynamics of body. AVP is a weaken constriction of renal blood vessel found in normal conditions because of antagonist of renal Prostaglandin. On the other hand, while the content of AVP in the kidney arise to an abnormal level, ARF will take place that renal bloodflow and glomerular filtration rates reduce rapid. There are some researches to prove that an inappropriate synthesis and release of AVP enhances during some renal diseases. But no studies focus on the changes of the AVP content in the body, especially those in the hypothalamus where AVP is released from brain to blood and cerebrospinal fluid. We examined the changes of vasopressin-immunoreactive neurons in the rats hypothalamus by immunohistochemistry in the process of acute renal failure so that we can understand more deeply on the possible role of AVP in ischemic renal injury. Methods:(1) Experiments were performed on adult, female SD rats. ARF was induced by clamping the right renal artery in rats, while the left kidney was cut away, and after 60 minutes , clamp was unfold, which induced the ischaemia-reperfusion injury of rats kidney. In the control group, subjects were sham-operated with one kidney untreated after separating both of the renal pedicles. The rats of ARF was divided into two groups, one of which sacrified 2 days later, and the other after 4 days. Blood samples were taken via heart in order to examine the level of plasma creatinine. The one-fold increase from the basal level meaned success of ARF models.(2) To measure the content of AVP in hypothalamus, we took the5following steps. Pours 4% citromint into body arteries via aorta in order to fix the brain. After that, brains were taken out of the rats' cranial cavities, which included the complete hypothalamus. We could mae serial freeze sections(about 10 u m) of brain. Among these section, those including the hypothalamic paraventricular and supraoptic nuclei were chosen for the SABC immunohistochemistry, and the grey density of the vasopressin-immunoreactive neurons, which has more AVP if it has higher grey density, were examined by image analysis software of LEICA QWIN and statistics. Result:(l)After operation, urine volume decreased in ARF groups. And compared loss of weight, we found that there was a similar loss of weight between the control and 2-day ARF groupes, while the subjects of 4-day ARF group lost the most weight. In the normal control rats, the level of the plasma creatinine after-operation sample produced less increases, which overall were not statistically different than those of before-operation. (p>0.05), on the other hand, subjects of ARF had more contend of creatinine in blood than those of control ones(p<0.05), especially on the 4-days ARF groups (p<0.01).(2)Sections of stained with HE showed the two nuclei: SON and PVN. Neurons in the SON located on both sides of optic chiasma of hypothalamus. The configuration of the nucleus was triangle, and thetop stretched inward with distinct limitation. Cell in the PVN gathered on both sides of the third ventricle of cerebrum. Both nuclei consisted of magnocellular, which the neurons in SON were larger than those in PVN with more plentiful cytoplasm. And in the neurons, nuclear located on one side clearly and area with shallow blue of cytoplasm occupied the other side of these cells.(3) The sections that stained by showed the posi...
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