Apoptosis In Rat Kidney Research Articles

Quercetin protects the rat kidney against oxidative stress-mediated DNA damage and apoptosis induced by lead

Quercetin, a flavonoid, effectively improved the lead-induced histology changes including structure damage and leukocyte infiltration in rat kidney. The present study was designed to explore the protective mechanism of quercetin against lead-induced oxidative DNA damage and apoptosis in rat kidney. We found that quercetin markedly decreased the ROS level and lowered the GSH/GSSG ratio in the kidney of lead-treated rat. The increase of 8-hydroxydeoxyguanosine level in the kidney of lead-treated rat was effectively suppressed by quercetin. Furthermore, quercetin markedly restored Cu/Zn-SOD, CAT and GPx activities in the kidney of lead-treated rat. TUNEL assay showed that lead-induced apoptosis in rat kidney was significantly inhibited by quercetin, which might be attributed to its antioxidant property. In conclusion, these results suggested that quercetin could protect the rat kidney against lead-induced injury by improving renal function, attenuating histopathologic changes, reducing ROS production, renewing the activities of antioxidant enzymes, decreasing DNA oxidative damage and apoptosis.

Renoprotective Potency of Heme Oxygenase-1 Induction in Rat Renal Ischemia-Reperfusion

Renal injury caused by ischemia-reperfusion (IR) can lead to acute renal failure or delayed graft function. Renal ischemia-reperfusion (RIR) induces inflammatory disorders via activation of arachidonic acid metabolism into prostaglandin E(2) (PGE(2)). Two inducible enzymes, COX-2 and microsomal prostaglandin E synthase (mPGES), regulate PGE(2) production. Heme oxygenase-1 (HO-1) is a cytoprotective enzyme activated during cellular stress. Overexpression of HO-1 is beneficial in transplantation models including antigen-independent IR injury, acute and chronic allograft rejection. We investigated the effect of HO-1 induction on the COX pathway, antioxidant enzyme activities, malondialdehyde (MDA) levels, and apoptosis in rat kidneys subjected to 45 min ischemia and 1 h or 24 h reperfusion. Rats were injected intraperitoneally with either: 50 mg/kg hemin (HO-1 inducer groups: H1, H2); 50 micromol/kg ZnPP (HO-1 inhibitor groups: Hz1, Hz2); or 0.9% saline (control groups: r1, r2). Sham animals (Sh) did not undergo RIR. Serum creatinine increased significantly after RIR (r vs Sh; p <0.05). Hemin treatment induced a significant decrease in serum creatinine after RIR (H vs r; p <0.05) whereas ZnPP treatment significantly increased serum creatinine levels (Sh vs Hz; p <0.05). Hemin reduced the severity of acute tubular necrosis and significantly reduced COX-2 and mPGES expression (p <0.05). Hemin did not alter depleted antioxidant enzyme activity but did decrease levels of MDA (p <0.05). Hemin also reduced caspase-3 expression. HO-1 decreased the degree and severity of tubular damage after IR, probably by attenuating the cytotoxic effects of inflammatory infiltrates and apoptosis.

Antioxidation and anti-inflammation by haem oxygenase-1 contribute to protection by tetramethylpyrazine against gentamicin-induced apoptosis in murine renal tubular cells

Gentamicin, a widely used antibiotic for the treatment of bacterial infection, can cause nephrotoxicity. Tetramethylpyrazine (TMP) is a compound purified from the rhizome of Ligusticum wallichi (called chuanxiong in Chinese). Besides its protection against ischaemia-reperfusion injury and nephritis in mice, we previously reported that TMP reverses gentamicin-induced apoptosis in rat kidneys. Haem oxygenase-1 (HO-1) induction by TMP has also been shown to attenuate myocardial ischaemia/reperfusion injury in rats. We used rat renal tubular (NRK-52E) cells, transformed cells with HO-1 overexpression or knockdown, and an adenovirus carrying the HO-1 gene (Adv-HO-1) as gene therapy targeting murine kidneys to explore the role of HO-1 in protection by TMP against gentamicin-induced toxicity both in vitro and in vivo. We evaluated the protective effects of HO-1 on several apoptotic parameters induced by gentamicin: cleaved caspases-3 and -9, cycloxygenase-2 (Cox-2) and subcellular localization of nuclear factor kappa B-p65 (NF-kappaB-p65), Bcl-xl and HS-1-associated protein (Hax-1) in NRK-52E cells. NRK-52E cells treated with TMP exhibited transcriptional upregulation of the HO-1 protein by approximately twofold. Overexpression of HO-1 in NRK-52E cells significantly increased mitochondrial protein levels of the antiapoptotic molecules, Bcl-xL and Hax-1, and markedly decreased the NADPH oxidase activity and proinflammatory molecules, NF-kappaB-p65 and Cox-2, which might decrease gentamicin-induced activation of caspases-9 and -3. Conversely, NRK-52E cells with HO-1 knockdown significantly exacerbated gentamicin-induced tubular cell apoptosis. Additionally, the concomitant HO-1 induction by TMP was also evident in vivo, and HO-1 therapy markedly attenuated gentamicin-induced renal apoptosis to a similar extent as TMP pretreatment. Collectively, we suggest that HO-1 induced by TMP might, at least in part, protect against gentamicin-induced nephrotoxicity through antiapoptotic and anti-inflammatory mechanisms, and that it may have therapeutic potential for patients with renal disease. This is also the first demonstration that HO-1 increases Hax-1 mitochondrial localization.

Role of apoptosis in the kidney after reperfusion

Organ transplantation is one of the most important achievements of medicine in the 20th century. Ischaemia-reperfusion has a great impact on both: immediate organ function and long-term survival. Organ transplantation can be regarded as a clinical model of ischaemia-reperfusion phenomenon. The prevention of ischaemia-reperfusion damages. Apoptosis plays a key-role in these processes. Apoptosis was investigated in the course of human kidney transplantation. In animal experiments the characteristics of apoptosis were analysed after short ischaemia. Calcium antagonists: verapamil, nifedipine, bepridil, fendiline and (-)-deprenyl, an irreversible selective inhibitor of monoamino oxidase type B, (-)-deprenyl, were administered to prevent apoptosis. The observations showed that in the course of human kidney transplantation necrotic, apoptotic and proliferating renal tubular cells can be observed. All calcium channel blockers and (-)-deprenyl decreased the occurrence and degree of apoptosis in rat kidney. The functional capacity of tubular cells is a significant factor in the adequate kidney function. The reduction of the apoptosis of tubular cells possibly could improve the function of transplanted kidneys.

Cisplatin-induced nephrotoxicity is associated with oxidative stress, redox state unbalance, impairment of energetic metabolism and apoptosis in rat kidney mitochondria

The clinical use of cisplatin (cis-diamminedichloroplatinum II) is highly limited by its nephrotoxicity. The precise mechanisms involved in cisplatin-induced mitochondrial dysfunction in kidney have not been completely clarified. Therefore, we investigated in vivo the effects of cisplatin on mitochondrial bioenergetics, redox state, and oxidative stress as well as the occurrence of cell death by apoptosis in cisplatin-treated rat kidney. Adult male Wistar rats weighing 200-220 g were divided into two groups. The control group (n = 8) was treated only with an intraperitoneal (i.p.) injection of saline solution (1 ml per 100 g body weight), and the cisplatin group (n = 8) was given a single injection of cisplatin (10 mg/kg body weight, i.p.). Animals were sacrificed 72 h after the treatment. The cisplatin group presented acute renal failure characterized by increased plasmatic creatinine and urea levels. Mitochondrial dysfunction was evidenced by the decline in membrane electrochemical potential and the substantial decrease in mitochondrial calcium uptake. The mitochondrial antioxidant defense system was depleted, as shown by decreased GSH and NADPH levels, GSH/GSSG ratio, and increased GSSG level. Moreover, cisplatin induced oxidative damage to mitochondrial lipids, including cardiolipin, and oxidation of mitochondrial proteins, as demonstrated by the significant decrease of sulfhydryl protein concentrations and increased levels of carbonylated proteins. Additionally, aconitase activity, which is essential for mitochondrial function, was also found to be lower in the cisplatin group. Renal cell death via apoptosis was evidenced by the increased caspase-3 activity. Results show the central role of mitochondria and the intensification of apoptosis in cisplatin-induced acute renal failure, highlighting a number of steps that might be targeted to minimize cisplatin-induced nephrotoxicity.

Exercise-induced apoptosis in rat kidney is mediated by both angiotensin II AT1 and AT2 receptors.

Excessive physical exercise may lead to disturbance of the entire homeostasis in the body, including damage not only in skeletal muscles but also in many distant organs. The mechanisms responsible for the exercise-induced changes could include oxidative stress or angiotensin II. We previously showed that acute exercise led to apoptosis in kidney but not as a result of oxidative stress. In this study, we examined the role of angiotensin II and its AT1 and AT2 receptors in mediation of exercise-induced apoptosis in kidney. We clearly demonstrated that acute physical exercise induced apoptosis in renal cells of distal convoluted tubuli and cortical and medullary collecting ducts. Moreover, the cells displayed an increased expression of both AT1 and AT2 angiotensin II receptors and of p53 protein. The results suggest that angiotensin II could upregulate p53 expression in renal distal convoluted tubular cells and in the cells collecting ducts via both AT1 and AT2 receptors, which might be the crucial apoptosis-mediating mechanism in kidneys after excessive exercise.

Sterile vesicoureteral reflux decreases tubular cell apoptosis in rat kidney

Objectives To assess the possible role of apoptosis in reflux-related renal scarring by investigating how sterile vesicoureteral reflux affects apoptosis of glomerular and tubular cells in the rat kidney. Methods Twenty-nine rats were assigned to one of three groups: group 1, reflux (n = 10); group 2, sham surgery (n = 9); and group 3, controls (n = 10). All rats underwent bilateral nephrectomy 42 days later. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling was used to detect the apoptotic cells, and separate apoptotic index values for glomerular cells (GCAI) and tubular cells (TCAI) were calculated in each kidney (left and right from each animal). Results The mean TCAI value in the left kidney from groups 1, 2, and 3 was 0.86% ± 0.26%, 1.20% ± 0.18%, and 1.19% ± 0.14%, respectively. The corresponding TCAI values for the right kidneys were 0.77% ± 0.21%, 1.10% ± 0.34%, and 1.06% ± 0.15%. The mean GCAI value in the left kidney from groups 1, 2, and 3 was 0.26% ± 0.14%, 0.28% ± 0.08%, and 0.20% ± 0.10%, respectively. The corresponding GCAI values for the right kidneys were 0.23% ± 0.06%, 0.26% ± 0.06%, and 0.22% ± 0.12%. Analysis revealed no significant differences among the groups with respect to GCAI in the left kidneys ( P = 0.258) or right kidneys ( P = 0.618). The mean TCAI values in group 1 were significantly lower than the corresponding values in groups 2 and 3 for the left ( P = 0.001) and right ( P = 0.012) kidneys. Conclusions This is the first study to have shown that sterile vesicoureteral reflux decreases apoptosis in tubular cells in rat kidneys with vesicoureteral reflux.

Cellular and molecular studies on cisplatin-induced apoptotic cell death in rat kidney.

Using morphological and molecular approaches, we characterized cisplatin-induced cell necrosis and apoptosis in rat kidney. Male Sprague-Dawley rats ( n=5 per group) received a single intraperitoneal injection of either cisplatin (5 mg/kg) or saline, and were killed on day 5. Functionally, cisplatin-treated rats developed polyuric acute renal failure. Morphologically, kidneys of cisplatin-treated rats showed overt tubular necrosis associated with apoptosis in the corticomedullary junction. Cell necrosis was segment-specific and was distributed in radial fashion at the corticomedullary junction. The apoptosis was limited to discrete cells in apparently intact tubules in the vicinity of the necrosed tubules. The apoptotic changes were confirmed by TUNEL (TdT-mediated deoxyuridine triphosphate nick-end labeling) and staining for cleaved caspase-3. Analysis of outer medullary tissue for apoptosis-related molecules by RNase protection assay revealed a significant increase in the expression of pro-apoptotic mRNAs (caspases 1, 2, and 8, and Bax) in cisplatin-treated rats. On the other hand, the expression of mRNA for the anti-apoptotic Bcl-2 did not change, resulting in a decrease in relative ratio of Bcl-2/Bax, and thus favoring apoptosis. The above changes were paralleled by a marked increase in caspase-3 precursor, the executioner protease. Furthermore, these pro-apoptotic molecular changes were associated with a 3-fold increase in the activity of JNK1 in the outer medulla, but not in the cortex, of cisplatin-treated rat kidneys, localizing to the site of maximal apoptosis. Upregulation of JNK1 activity in the outer medulla was not accompanied by changes in the activities of ERK or p38 kinase. In conclusion, these data suggest that cisplatin-induced apoptotic cell death in native kidney may be mediated by cooperative activation of the JNK1 pathway and Bax in the outer medulla.

Cadmium-bound metallothionein induces apoptosis in rat kidneys, but not in cultured kidney LLC-PK 1 cells

The ability of cadmium-bound metallothionein(Cd-MT) to induce apoptosis was investigated in vivo and in vitro. Administration of purified Cd-MT (0.15 mg MT bound Cd per kg body weight) to the rat induces DMA fragmentation, a biochemical characteristic of apoptosis in the kidney at 16 h, which was detectable by ethidium bromide staining on an agarose gel. It was still detected 24h after administration. Induction of apoptosis by Cd-MT was specific to kidney; it was not observed in cerebrum, cerebellum, heart, lung, liver, testis, dorsolateral prostate, and ventral prostate. In contrast, addition of Cd-MT (0.01–100 μM) to the cultured porcine kidney LLC-PK 1 cells failed to induce apoptosis under the condition where cadmium chloride (10 μM) did. There was no additivity of induction of apoptosis by CdCl 2 (10 μM) in the presence of Cd-MT (0.01–100 μM). To examine the effect of intracellular MT on cadmium — induced apoptosis in cultured cells, new cell lines were established, which constitutively produce MT, being termed as Cd r-LLC-PK 1 cells since Cd-MT exogenously added had much less permeability to the cultured cells. Followed by exposure of wild-type LLC-PK 1 cells to 50 μM CdCl 2 for 24 h, the surviving cells(Cd r-LLC-PK 1 cells) Induce MT at the level of 1.9 μg /2 × 10 6 cells. In Cd r-LLC-PK 1 cells, 10 μM CdCl 2failed to induce apoptosis, but 60 μM CdCl 2 could exert the apoptotic response, indicating that intracellular MT which was induced by CdCl 2 did not facilitate CdCl 2-elicited apoptosis. Furthermore, chromatin in rat kidneys was condensed by Cd-MT, but not that in LLC-PK 1 cells. Thus, Cd-MT induces apoptosis in rat kidneys, but not in the cultured renal cells, suggesting that the ionic form of cadmium was required for programmed cell death.

Protective Effects of KW-3902, an Adenosine A1-Receptor Antagonist, Against Cisplatin-Induced Apoptosis in Rat Kidney.

We histopathologically examined rat kidneys which were obtained 1 hour, 1 day, and 3 days after a single administration of cisplatin (CDDP). Pretreatment with KW-3902 (0.1 mg/kg) reduced an increase in TUNEL-positive tubular cells on day 1 and day 3. On day 1 and thereafter, in the CDDP-treated groups, ultrastructural examination revealed findings characteristic of apoptosis such as nuclear chromatin condensation of the proximal tubular epithelia. Moreover, we determined the effect of KW-3902 on the CDDP content of urine, blood, and kidney in rats. Pretreatment with KW-3902 (0.1 mg/kg) did not affect plasma CDDP concentration or cumulative urinary excretion of CDDP, until 40 min after a bolus injection of CDDP, but induced diuresis, resulting in decreased urinary concentration of CDDP and reduced accumulation of CDDP in the kidney. These results suggest that the protective effect of KW-3902 against CDDP-induced acute renal failure is at least partly attributable to reduced apoptosis of the proximal tubular epithelium, possibly resulting from the reduction of CDDP accumulation in the same place.

Diabetes-Induced Apoptosis in Rat Kidney

Oxidative stress has been suggested to play a crucial role in the pathogenesis of diabetic complications including nephropathy. However, the exact mechanism of diabetic nephropathy is still not clearly understood. Since oxidative stress is known to be a major component in the induction of apoptosis, we investigated the occurrence of apoptosis in diabetic rat kidney. The status of oxidative stress was determined as thiobarbituric acid reactive substances (TBARS). The TBARS in the control and diabetic rat kidney were 2.00 ± 0.963 and 3.83 ± 0.715 μmol/mg protein, respectively (P< 0.05). Apoptosis was determined by evaluating the DNA fragmentation using an enzyme-linked immunoassay andin situend labeling. DNA fragmentation increased approximately fourfold in diabetic rat kidney compared to the normal kidney (P< 0.05). Apoptagin situlabeling displayed negligible apoptosis in nondiabetic kidney while significant areas of apoptosis were observed in diabetic kidney. Our results suggest that increased oxidative stress in diabetic kidney could induce apoptosis, which may contribute to the development of diabetic nephropathy.