Strain of experimental animals and modulation of nitric oxide pathway: their influence on development of renal failure in an experimental model of hepatorenal syndrome

Role of Probiotic Mixture with and Without Green Tea Extract in Prevention of Hepatorenal Syndrome in Rat Model

BACKGROUND AND OBJECTIVE

Hepatorenal syndrome (HRS) is a major public health problem in which both liver and kidney dysfunctions are encountered. The present research aimed to investigate the beneficial use of micro-encapsulated probiotic alone (Bifidobacterium bifidum, Lactobacillus delbrueckii and Streptococcus thermophilus mixture) or with green tea alcohol extract in HRS model in rats.

MATERIALS AND METHODS

Flavonoids content and in vitro antioxidant activity of the extract were assessed. The animal experiment consisted of 4 groups; control healthy, control with HRS and two test groups with HRS and treated with either the encapsulated probiotic mixture alone or with green tea extract. After 3 weeks; urinary creatinine was determined in 24 h rat urine samples. Colonic microbiota was assessed in faeces. Plasma malondialdehyde, nitrite, C-reactive protein, creatinine, uric acid, urea and the activity of transaminases, catalase (CAT) and angiotensin-1 converting enzyme (ACE-1) were determined with calculation of creatinine clearance.

RESULTS

Results showed significant increase in all biochemical parameters of HRS control except for ACE-1, CAT and creatinine clearance that experienced significant reduction along with dysbiosis compared to healthy control. Test groups showed improvement in all biochemical parameters with superiority to probiotic-green tea extract combination. Both treatments produced significant increase in fecal B. bifidum, S. thermophilus and L. bulgaricus and reduction of Staphylococci and Coliform. The effect of probiotic-green tea extract combination was more pronounced concerning the last three. Flavonoids and antioxidant activity of the extract were 1.325±0.01 mg quercetin/g and 98±1.66%, respectively.

CONCLUSION

Administration of micro-encapsulated probiotic with or without alcohol green tea extract exerted significant prevention of HRS in rat with superiority to probiotic-green tea extract combination.

Protective Effects of the Third Generation Vasodilatory Βeta - Blocker Nebivolol against D-Galactosamine - Induced Hepatorenal Syndrome in Rats

BACKGROUND:

Renal dysfunction is very common in patients with advanced liver cirrhosis and portal hypertension. The development of renal failure in the absence of clinical, anatomical or pathological causes renal of failure is termed hepatorenal syndrome (HRS).

AIM:

The present study was constructed to investigate the possible protective effects of nebivolol (Nebi) against D-galactosamine (Gal)-induced HRS in rats.

MATERIAL AND METHODS:

Rats were treated with Nebi for ten successive days. On the 8th day of the experiment, they received a single dose of Gal. Serum levels of Cr, BUN, Na+ and K+ as well as AST, ALT, total bilirubin (TB), NH3 and endothelin-1 (ET-1) were determined following Gal administration. Moreover, renal and liver contents of MDA, GSH, F2-isoprostanes (F2-IPs), tumor necrosis factor-alpha (TNF-α), nuclear factor kappa-B (NF-κB), total nitric oxide (NO), in addition to activities of caspase-3 (Cas-3), heme oxygenase-1 (HO-1), inducible and endothelial NO synthase (iNOS and eNOS) enzymes were also assessed. Finally, histopathological examination was performed.

RESULTS:

Nebi attenuated Gal-induced renal and hepatic dysfunction. It also decreased the Gal-induced oxidative stress and inflammatory recruitment.

CONCLUSION:

Results demonstrated both nephroprotective and hepatoprotective effects of Nebi against HRS and suggested a role of its antioxidant, anti-inflammatory, anti-apoptotic and NO-releasing properties.

Role of Nitric Oxide Pathway in Development and Progression of Chronic Kidney Disease in Rats Sensitive and Resistant to its Occurrence in an Experimental Model of 5/6 Nephrectomy

BACKGROUND Understanding the mechanisms conditioning development of chronic kidney disease (CKD) is still a challenge. The aim of this study was to evaluate the activity of the intrarenal nitric oxide (NO) pathway in the context of sensitivity or resistance of different animal strains to the development and degree of renal failure. MATERIAL AND METHODS Two rat strains were used: Wistar (WR) and Sprague-Dawley rats (SDR) in a model of CKD - 5/6 nephrectomy. We assessed parameters of renal failure and expression of nitric oxide synthase (NOS) isoforms in renal cortex and medulla. RESULTS We did not observe renal failure in WR, and CKD developed in SDR with increase of creatinine and urea concentration as well as decrease of diuresis and glomerular filtration. In the renal cortex, baseline expression of NOS2 was higher in WR than in SDR. 5/6 nephrectomy resulted in reduction of NOS2 in both strains and NOS3 in WR. In the renal medulla, baseline NOS2 expression was higher in SDR, and nephrectomy resulted in its decrease only in SDR. Although baseline NOS3 expression was higher in SDR, the NOS3 expression after nephrectomy was higher in WR rats. CONCLUSIONS In model of CKD - 5/6 nephrectomy, SDR proved to be sensitive and WR resistant to development of CKD. The intrarenal activity of the nitric oxide pathway was the factor that differentiated both strains. This mechanism may be responsible for insensitivity of WR to development of renal failure in this model of CKD.

Concerted regulation of renal plasma flow and glomerular filtration rate by renal dopamine and NOS I in rats on high salt intake

Under high sodium intake renal dopamine (DA) increases while NOS I expression in macula densa cells (MD) decreases. To explore whether renal DA and NOS I, linked to natriuresis and to the stability of the tubuloglomerular feedback, respectively, act in concert to regulate renal plasma flow (RPF) and glomerular filtration rate (GFR). Male Wistar rats were studied under a normal sodium intake (NS, NaCl 0.24%) or a high sodium intake (HS, NaCl 1% in drinking water) during the 5 days of the study. For the last two days, the specific D1-like receptor antagonist SCH 23390 (1 mg kg bwt-1 day-1, sc) or a vehicle was administered. HS intake increased natriuresis, diuresis, and urinary DA while it decreased cortical NOS I expression (P < 0.05 vs. NS), Nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity in MD (P < 0.001 vs. NS) and cortical nitrates+nitrites (NOx) production (NS 2.04 ± 0.22 vs. HS 1.28 ± 0.10 nmol mg protein-1, P < 0.01). Treatment with SCH 23390 to rats on HS sharply decreased hydroelectrolyte excretion (P < 0.001 vs. HS) while NOS I expression, NADPH-d activity and NOx production increased (P < 0.05 vs. HS for NOS I and P < 0.001 vs. HS for NADPH-d and NOx). SCH 23390 increased RPF and GFR in HS rats (P < 0.01 HS+SCH vs. HS). It did not cause variations in NS rats. Results indicate that when NS intake is shifted to a prolonged high sodium intake, renal DA through the D1R, and NOS I in MD cells act in concert to regulate RPF and GFR to stabilize the delivery of NaCl to the distal nephron.

D-Galactosamine Intoxication in Experimental Animals: Is it Only an Experimental Model of Acute Liver Failure?

BACKGROUND

Short-term administration of Galactosamine to experimental animals causes liver damage and acute liver failure (ALF), as well as acute renal failure in some cases. The aim of our study was to describe kidney disorders that developed in the course of galactosamine-induced liver failure.

MATERIAL AND METHODS

Sprague-Dawley rats were randomly divided into 2 groups: a study group administered galactosamine intraperitoneally and a control group administered saline.

RESULTS

All the animals in the study group developed liver damage and failure within 48 h, with significant increase of alanine (p<0.001), aspartate aminotransferases (p<0.0001), bilirubin (p<0.004), and ammonia (p<0.005) and decrease of albumin (p<0.001) concentrations. Acute renal failure was observed in all test animals, with a significant increase in creatinine (p<0.001) and urea (p<0.001) concentrations and a decrease in creatinine clearance (p<0.0012). Moreover, osmotic clearance (p<0.001), daily natriuresis (p<0.003), and fractional sodium excretion (p<0.016) decreased significantly in this group of animals. The ratio of urine osmolality to serum osmolality did not change. Histopathology of the liver revealed massive necrosis of hepatocytes, whereas renal histopathology showed no changes.

CONCLUSIONS

Acute renal failure that developed in the course of galactosamine-induced ALF was of a functional nature, with the kidneys retaining the ability to concentrate urine and retain sodium, and there were no renal changes in the histopathological examination. It seems that the experimental model of ALF induced by galactosamine can be viewed as a model of hepatorenal syndrome that occurs in the course of acute damage and liver failure.

Effect of nitric oxide pathway regulation on water/sodium balance and renal function in a rodent model of acute liver and renal failure

BACKGROUND

The pathomechanism of acute hepatorenal syndrome (HRS), a particular form of acute renal failure that occurs in the course of acute liver injury, is still poorly understood. The aim of our study was to estimate the influence of the activation and inhibition of the nitric oxide pathway on the water/sodium balance and development of acute renal failure in the course of HRS.

MATERIAL AND METHODS

We used male Sprague-Dawley rats in the acute galactosamine (Ga1N) model of HRS. The nitric oxide synthase (NOS) inhibitors L-NAME and L-arginine were administered intraperitoneally before and after liver damage.

RESULTS

HRS developed in all tested groups. L-NAME increased osmotic clearance and urine volume more effectively before liver injury. Furthermore, administration of L-NAME increased creatinine clearance both before and after Ga1N injection. A double dose of L-NAME did not yield further improvement before Ga1N injection, but improved creatinine clearance after Ga1N intoxication. Injection of L-arginine increased sodium excretion and urine volume, but only after liver injury. Moreover, L-arginine injected after Ga1N caused significant improvement of the creatinine clearance in a dose-dependent manner.

CONCLUSIONS

Our study shows that inhibition of the nitric oxide pathway improves parameters of water and sodium balance and prevents development of acute renal failure in the course of acute liver injury and liver failure. Activation of the nitric oxide system also has a favorable influence on water/sodium balance and renal failure, but only after liver injury.

Therapeutic effects of octreotide combined with alprostadil on cirrhosis with hepatorenal syndrome

AIM: To explore the therapeutic effects of octreotide combined with alprostadil on cirrhosis with hepatorenal syndrome.

METHODS: Sixty patients with cirrhosis and hepatorenal syndrome were randomly divided into two groups: a control group and an experimental group. The control group was treated by conventional treatment, while the experimental group was additionally given octreotide combined with alprostadil on the basis of conventional treatment. The indexes of renal function, hemodynamic parameters, diameters of the portal vein and splenic vein, and clinical effects were compared.

RESULTS: In the experiment group, the levels of BUN and SCr were significantly lower (10.15 mmol/L ± 5.02 mmol/L vs 19.02 mmol/L ± 7.45 mmol/L, 136.13 μmol/L ± 18.62 μmol/L vs 211.42 μmol/L ± 17.66 μmol/L, P < 0.05) and the level of 24 h urine volume was significantly higher (1644.36 mL/d ± 178.30 mL/d vs 443.41 mL/d ± 77.88mL/d, P < 0.05) after treatment than before treatment. In the control group, the level of SCr was significantly lower (152.60 μmol/L ± 16.89 μmol/L vs 207.12 μmol/L ± 16.27 μmol/L, P < 0.05) and the level of 24 h urine volume was significantly higher (1207.26 mL/d ± 177.05 mL/d vs 459.51 mL/d ± 90.37mL/d, P < 0.05) after treatment than before treatment. The levels of BUN and SCr were significantly lower (10.15 mmol/L ± 5.02 mmol/L vs 15.72 mmol/L ± 7.71 mmol/L, 136.13 μmol/L ± 18.62 μmol/L vs 152.60 μmol/L ± 16.89 μmol/L, P < 0.05) and the level of 24 h urine volume was significantly higher (1644.36 mL/d ± 178.30 mL/d vs 1207.26 mL/d ± 177.05 mL/d, P < 0.05) in the experimental group than in the control group. There were no significant differences in the levels of MAP and HR between before and after treatment in both groups (78.45 mmHg ± 4.01 mmHg vs 76.44 mmHg ± 4.06 mmHg, 84.08/min ± 4.70/min vs 86.22/min ± 4.67/min, 78.53 mmHg ± 4.17 mmHg vs 78.22 mmHg ± 4.08 mmHg, 84.77/min ± 4.34/min vs 85.55/min ± 4.58/min, P > 0.05). The diameters of the portal vein and splenic vein were significantly lower (11.99 mm ± 1.33 mm vs 14.02 mm ± 1.37 mm, 8.16 mm ± 1.20 mm vs 10.65 mm ± 1.57 mm, 13.05 mm ± 1.16 mm vs 13.94 mm ± 1.27 mm, 9.36 mm ± 1.61 mm vs 10.50 mm ± 1.61 mm, P < 0.05) after treatment than before treatment in both groups. The diameters of the portal vein and splenic vein in the experiment group were significantly lower than those in the control group (11.99 mm ± 1.33 mm vs 13.05 mm ± 1.16 mm, 8.16 mm ± 1.20 mm vs 9.36 mm ± 1.61 mm, P < 0.05). The improvement rate and the total response rate in the experimental group were significantly higher than those in the control group (20.00% vs 6.67%, 83.33% vs 46.67%, P < 0.05), although there was no significant difference in mortality (6.67% vs 6.67%, P > 0.05).

CONCLUSION: Octreotide combined with alprostadil can improve renal function, reduce the portal pressure, has less impact on haemodynamics and high safety in patients with cirrhosis with hepatorenal syndrome.