Gene expression of vasopressin receptor type 2 and aquaporin 2 in acute renal failure versus chronic renal failure in rats

Urinary concentration decreases in response to a reduction of functioning renal mass. Although a variety of factors have been implicated, the pathogenesis of impaired urinary concentration ability in acute renal failure [ARF] and in chronic renal failure [CRF] especially the cellular and molecular defects, were poorly understood. Our study therefore aimed to present a possible explanation for the pathogenesis of impaired urinary concentration and the molecular defect in kidney tissue of experimental ARF and CRF rat models and aimed to find and compare any molecular defect difference between ARF and CRF. Thirty albino adult male rats were used in our study and the animals were divided into three groups. Group I: Sham-operated controls [n=10]. Group II: Renal ischemia-reperfusion injury group [n=10] in which the renal artery and vein were bilaterally exposed and occluded for 30min with vascular clamps to produce renal ischemia-induced acute renal failure [ARF], the clamps were removed to allow kidney reperfusion then the animal sacrified after 24H. Group III: Chronic renal failure group [n=10], this group of animals underwent right total nephrectomy and removal of 2/3 of the left kidney and the experimental protocol lasted about one month then the animals were sacrified. Blood, urine and kidney tissue samples were collected from the three groups to measure serum urea and creatinine and 24 hour-urinary albumin for evaluation of kidney function and to measure aquaporin 2 water channel and vasopressin-receptor type 2 [V[2]] gene expressions in kidney tissue. Kidney function tests as regards serum urea, serum creatinine and 24 hour-urinary albumin in group II and group III showed a significant [p<0.05] increase in comparison to control group [group I]. Ischemic-reperfusion rats [group II] showed the highest of these parameters indicating that, they had the worst kidney function. A significant [p<0.05] decrease in vasopressin-receptor type 2 [V[2]] mRNA expression in kidney tissue was shown in group II [ARF] and group III in comparison to the control rats [group I] with the highest reduction in group II. A similar result was found as regards Aquaporin 2 water channel mRNA expression with a significant [p<0.05] reduction in group II and group III in comparison to group I, and the highest reduction was seen in group II among the three studied groups. In both ischemia-reperfusion rats and CRF rats, the ischemic and nephrectomy insults were associated with decreased mRNA expression of the aquaporin 2 and vasopressin-receptors type 2 [V[2]] in the kidney tissue, coinciding with the impairment of kidney function. This may contribute to the impairment in urinary concentration in the post-ischemic period and the urinary concentration defect associated with CRF

Annexin V as index of apoptosis in aorta of STZ induced diabetic rats

Diabetes mellitus [DM] is a chronic disease associated with hyperglycemia and the production of reactive oxidative intermediates and a disturbed antioxidant defense mechanism. Apoptosis or programmed cell death is a fundamental component of tissue differentiation and development, it also plays a central role in DM. The highly regulated mechanism of apoptosis involves an externalization process of phosphatidylserine [Ps]. Annexin V binds with high affinity to Ps-exposing apoptotic cell and can inhibit thereby the procoagulant and proinflammatory activities of the dying cell. Heat shock proteins have been shown to protect organism in vitro and in vivo against oxidative stress which plays a role in apoptosis in DM. HSP72 inhibits mitochondria! cytochrome release and subsequent caspase activation that leads to apoptosis. Fifty male albino rats weighing 170-200gm were used in this study. They were divided in to 5 equal groups, each of 10 rats. Group I: Control group. Group II: Diabetic group. Type 2 diabetes mellitus was induced by intraperitoneal injection of streptozotocin at a dose of 40mg/kg body weight. Group III: Diabetic group, treated with 1 unit insulin injected subcutaneously daily. Group IV: Diabetic group, receiving vit. E 600mg/kg B.Wt injected intramuscularly, 3 times/week, All groups were sacrified one month after the beginning of the experiment. Blood samples were obtained from retro-orbital vein for assessment of glucose and malondialdehyde [MDA], then Animals were sacrificed and aortic tissues were removed,PCR for Annexin V and for HsP72 were done. Compared to control group, fasting serum glucose is significantly higher in the diabetic group [group II] [p<0.05] and it decreased significantly with administration of insulin [group III]. MDA is significantly higher in the diabetic group II compared with control one [p<0.05]. It decreased significantly with administration of insulin [group III] or vitamin E [group IV] in comparison to diabetic group [group II]. Administration of vitamin E and insulin [group V] leads to significant reduction in MDA back to control level. The expression of Annexin V is significantly higher in the diabetic group [group II] compared to control group [p<0.05]. Administration of insulin [group III] or vitamin E [group IV] decreases it significantly. The expression of HSP72 is significantly lower in the diabetic group compared to control one [p<0.05]. It increased significantly with administration of insulin [group III] or vitamin E [group IV]. Serum MDA level rise in STZ induced diabetic rats as a marker of oxidative stress and administration of vitamin E was found to normalize this level, in addition a significant rise in expression of Annexin V as a marker of apoptosis in aorta of STZ induced diabetic rats with decreased expression of HSP72 which may be involved in cellular protection against oxidative stress in DM

Sex hormones and adrenocorticotropic hormone [ACTH] alterations during sleep deprivation and recovery in adult male rats

Positive association between sleep efficiency and plasma testosterone level in men was demonstrated by previous studies. Stresses in general and sleep deprivation in particular alter the male reproductive function and several studies indicate that sleep deprivation alters male sex hormones levels. Low sleep efficiency was associated with attenuated testosterone level. However, little information was available about the alterations of male sex hormones during the recovery period following the sleep deprivation. So, the purpose of the present study was to investigate the influence of 4-days recovery periods after 4-days sleep deprivation on male sex hormones and the role of ACTH hormone during both deprivation and recovery periods. Sixty four male albino rats weighing 200-250g each, were randomly distributed into three experimental sets: sleep deprived [SD] groups, recovery [R] groups and control group. The SD rats [n=24] were divided into 4 groups: SD1, SD2, SD3, and SD4 groups [each included 6 rats] that were subjected to SD for 1, 2, 3, and 4 days respectively. The recovery rats [n=24] were also divided into 4 groups [each included 6 rats] that were sleep deprived for 4 days and had left for recovery for 1, 2, 3, and 4 days; corresponding to R1, R2, R3 and R4 groups respectively. Finally, the control group included 16 rats. At the end of each group preparation, rats [control, SD and R] were sacrificed and plasma samples were collected for further measurement of testosterone, estradiol, progesterone and ACTH hormones. Compared to control rats, SD rats showed a significant [p