Monte Carlo Optimization Method Based QSAR Modeling of Placental Barrier Permeability.

PURPOSE: In order to ensure that drug administration is safe during pregnancy, it is crucial to have the possibility to predict the placental permeability of drugs in humans. The experimental method which is most widely used for the said purpose is in vitro human placental perfusion, though the approach is highly expensive and time consuming. Quantitative structure-activity relationship (QSAR) modeling represents a powerful tool for the assessment of the drug placental transfer, and can be successfully employed to be an alternative in in vitro experiments. METHODS: The conformation-independent QSAR models covered in the present study were developed through the use of the SMILES notation descriptors and local molecular graph invariants. What is more, the Monte Carlo optimization method, was used in the test sets and the training sets as the model developer with three independent molecular splits. RESULTS: A range of different statistical parameters was used to validate the developed QSAR model, including the standard error of estimation, mean absolute error, root-mean-square error (RMSE), correlation coefficient, cross-validated correlation coefficient, Fisher ratio, MAE-based metrics and the correlation ideality index. Once the mentioned statistical methods were employed, an excellent predictive potential and robustness of the developed QSAR model was demonstrated. In addition, the molecular fragments, which are derived from the SMILES notation descriptors accounting for the decrease or increase in the investigated activity, were revealed. CONCLUSION: The presented QSAR modeling can be an invaluable tool for the high-throughput screening of the placental permeability of drugs.

Melatonin arrests excessive inflammatory response and apoptosis in lipopolysaccharide-damaged rat liver: A deeper insight into its mechanism of action.

Sepsis is a life-threatening organ dysfunction. An animal model mimicking sepsis utilizes lipopolysaccharide (LPS), an endotoxin recognized as the most potent bacterial mediator of sepsis. Melatonin (MLT), an effective anti-inflammatory and antioxidant agent, is a promising adjunctive drug for sepsis. This study aimed to estimate the potential of MLT in preventing LPS-induced liver damage in Wistar rats by determining the levels of serum and tissue biochemical markers that reflect liver state and function, i.e., serum levels of transaminases and albumin, as well as a panel of oxidative stress-related biomarkers. Additionally, a pathohistological analysis of liver tissue was conducted. Pre-treatment with MLT prevented an LPS-induced increase in serum and tissue liver damage markers and a decrease in the tissue antioxidant capacity, in both enzymatic and non-enzymatic systems. Micromorphological liver tissue changes mirrored the alterations observed in the biochemical status. In rats with LPS-induced sepsis, melatonin was shown to be a crucial antioxidant and anti-inflammatory agent, with vital roles in the alleviation of oxidative stress, causing an increase of the antioxidant capacities and the improvement of the liver's microscopic appearance.

Acutely applied melatonin prevents CCl4-induced testicular lesions in rats: the involvement of the oxidative capacity and arginine metabolism

Abstract Carbon tetrachloride (CCl4) represents an organic chemical that causes reactive oxygen species derived organ disturbances including male infertility. Melatonin (MLT) is a neurohormone with strong antioxidant capacity, involved in numerous physiological processes. In this study we evaluated the capability of MLT, administered in a single dose of 50 mg/kg, to preserve the testicular tissue function after an acute administration of CCl4 to rats. The disturbance in testicular tissue and the effects of MLT after CCl4 exposure were estimated using biochemical parameters that enabled us to determine the tissue (anti)oxidant status and the intensity of arginine/nitric oxide metabolism. Also, the serum levels of testosterone and the histopathological analysis of tissue gave us a better insight into the occurring changes. A significant diminution in tissue antioxidant defences, arginase activity and serum testosterone levels, followed by the increased production of nitric oxide and extensive lipid and protein oxidative damage, was observed in the CCl4-treated group. The application of MLT after the CCl4 caused changes, clearly visible at both biochemical and histological level, which could be interpreted mainly as a consequence of general antioxidant system stimulation and a radical scavenger. On the other hand, the application of MLT exerted a limited action on the nitric oxide signalling pathway.

The Impact of Hepatitis C Virus Genotypes on Oxidative Stress Markers and Catalase Activity.

Hepatitis C virus (HCV) is a major cause of liver disease worldwide. Chronic HCV infections are usually associated with increased oxidative stress in the liver tissue. The intensity of oxidative stress may be a detrimental factor in liver injury and may determine the severity of the disease. The aim of the present case-control study was to determine the level of lipid peroxidation (TBARS), protein oxidative modification (AOPP), and catalase activity in sera of patients infected with HCV, in relation to different HCV genotypes and viral load. Considering the HCV patients with chronic hepatitis C (52) and control subject (50) recruitment, the study was designed as a case-control-type. The HCV RNA isolation, viral load, and HCV genotyping were performed according to the standard protocols. A significant difference compared to control healthy subjects was reported for TBAR (p < 0.001), AOPP (p = 0.001), and catalase activity (p = 0.007). In a gender-based comparison, a significantly higher level of AOPP for females was reported (p < 0.001). As stratified by HCV genotype, the most common was HCV-1 (HCV-1a and HCV 1b), with the overall participation of more than 60%, followed by genotype 3, while the least represented was genotype 2. No significant difference was documented among genotypes in regard to oxidative stress markers, although somewhat higher TBARS level, but not significant, was registered in patients infected with genotype 1b. A statistically significant positive correlation was found between the concentration of HCV genome copies and AOPP (r = 0.344; p = 0.012). A high level of HCV viral load was more likely to have a higher TBARS, but still without statistical significance (p = 0.072). In conclusion, the results obtained confirmed an imbalance between the ROS production and antioxidative defense system in HCV-infected patients. Since oxidative stress may have a profound influence on disease progression, fibrosis, and carcinogenesis, our results may meet the aspirations of mandatory introduction of antioxidants as early HCV therapy to counteract ROS consequences.

Anthocyanins Protect Hepatocytes against CCl4-Induced Acute Liver Injury in Rats by Inhibiting Pro-inflammatory mediators, Polyamine Catabolism, Lipocalin-2, and Excessive Proliferation of Kupffer Cells.

: This study examined the hepatoprotective and anti-inflammatory effects of anthocyanins from Vaccinim myrtillus (bilberry) fruit extract on the acute liver failure caused by carbon tetrachloride-CCl4 (3 mL/kg, i.p.). The preventive treatment of the bilberry extract (200 mg anthocyanins/kg, orally, 7 days) prior to the exposure to the CCl4 resulted in an evident decrease in markers of liver damage (glutamate dehydrogenase, sorbitol dehydrogenase, malate dehydrogenase), and reduced pro-oxidative (conjugated dienes, lipid hydroperoxide, thiobarbituric acid reactive substances, advanced oxidation protein products, NADPH oxidase, hydrogen peroxide, oxidized glutathione), and pro-inflammatory markers (tumor necrosis factor-alpha, interleukin-6, nitrite, myeloperoxidase, inducible nitric oxide synthase, cyclooxygenase-2, CD68, lipocalin-2), and also caused a significant decrease in the dissipation of the liver antioxidative defence capacities (reduced glutathione, glutathione S-transferase, and quinone reductase) in comparison to the results detected in the animals treated with CCl4 exclusively. The administration of the anthocyanins prevented the arginine metabolism's diversion towards the citrulline, decreased the catabolism of polyamines (the activity of putrescine oxidase and spermine oxidase), and significantly reduced the excessive activation and hyperplasia of the Kupffer cells. There was also an absence of necrosis, in regard to the toxic effect of CCl4 alone. The hepatoprotective mechanisms of bilberry extract are based on the inhibition of pro-oxidative mediators, strong anti-inflammatory properties, inducing of hepatic phase II antioxidant enzymes (glutathione S-transferase, quinone reductase) and reduced glutathione, hypoplasia of Kupffer cells, and a decrease in the catabolism of polyamines.

Protective effects of anthocyanins from bilberry extract in rats exposed to nephrotoxic effects of carbon tetrachloride.

This study examined the nephroprotective effects of 15 different anthocyanins from the bilberry extract on the acute kidney injury caused by CCl4. The acute nephrotoxicity in rats was induced 24 h after the treatment with a single dose of CCl4 (3 mL/kg, i.p.).The nephroprotective effects of the anthocyanins were examined in the animals that had been given the bilberry extract in a single dose of 200 mg of anthocyanins/kg daily, 7 days orally, while on the seventh day, 3 h after the last dose of anthocyanins, the animals received a single dose of CCl4 (3 mL/kg, i.p.) and were sacrificed 24 h later. When the nephrotoxicant alone was administered, it resulted in a substantial increase of the pro-oxidative (TBARS, CD, H2O2, XO, and GSSG) and pro-inflammatory markers (TNF-α, NO, and MPO), as well as a noticeable reduction of the antioxidant enzymes (CAT, SOD, POD, GPx, GST, GR) and GSH when compared to the results of the control group. Moreover, the application of CCl4 significantly influenced a reduction of the renal function, as well as an increase in the sensitive and specific injury indicators of the kidney epithelial cells (ß2-microglobulin, NGAL, KIM1/TIM1) in the serum and urine of rats. The pretreatment of the animals poisoned with CCl4 with the anthocyanins from the bilberry extract led to a noticeable reduction in the pro-oxidative and pro-inflammatory markers with reduced consumption of the antioxidant defence kidney capacity, compared to the animals exposed to CCl4 alone. Anthocyanins have been protective for the kidney parenchyma, with an apparent absence of the tubular and periglomerular necrosis, severe degenerative changes, inflammatory mononuclear infiltrates and dilatation of proximal and distal tubules, in contrast to the CCl4-intoxicated animals. The nephroprotective effects of anthocyanins can be explained by strong antioxidant and anti-inflammatory effects achieved through the stabilization and neutralization of highly reactive and unstable toxic CCl4 metabolites.

The Effects of Melatonin on Oxidative Stress Parameters and DNA Fragmentation in Testicular Tissue of Rats Exposed to Microwave Radiation.

BACKGROUND: Microwaves from mobile phones are one of the environmental toxicants that are capable of compromising male fertility by inducing oxidative stress and apoptosis in the testes. Melatonin is a lipophilic tryptophan indole amine and a potent antioxidant. OBJECTIVES: The aim of the study was to evaluate the effect of melatonin treatment on oxidative stress parameters and DNA fragmentation in the testicular tissue of rats exposed to microwave radiation (4 h/day). MATERIAL AND METHODS: Adult Wistar rats were divided in 4 groups: I--treated with saline; II--treated with melatonin; III--exposed to microwaves; IV--exposed to microwaves and treated with melatonin. The melatonin (2 mg/kg ip) was administered daily. The animals were sacrificed after 20, 40 and 60 days. RESULTS: Melatonin treatment prevented previously registered increases in malondialdehyde after only 20 days. Furthermore, it reversed the effects of microwave exposure on xanthine oxidase (after 40 days) and acid-DNase activity (after 20 days). However, neither protein carbonyl content nor catalase and alkaline Dnase activity were changed due to melatonin treatment. CONCLUSIONS: Melatonin exerts potent antioxidant effects in the testes of rats exposed to microwaves by decreasing the intensity of oxidative stress; it also reduces DNA fragmentation.

Melatonin protects rat thymus against oxidative stress caused by exposure to microwaves and modulates proliferation/apoptosis of thymocytes.

The aim of the study was to evaluate the effect of melatonin on oxidative stress, DNA fragmentation, apoptsis and proliferation in thymus tissue of rats exposed to microwaves. Wistar rats were divided in four groups: I - treated with saline; II - treated with melatonin; III - microwaves exposed; IV - microwaves exposed and melatonin treated. Melatonin (2 mg/kg i.p.) was administered daily. Animals were sacrificed after 20, 40 and 60 days. A significant increase in malondialdehyde and carbonyl group content, as well as decrease in catalase and increase in xanthine oxidase activity were registered under microwave exposure. Melatonin prevented the increase in malondialdehyde and carbonyl group content, and reversed the effect on catalase and xanthine oxidase activity. Both, alkaline and acid DNase activity were increased due to microwave exposure. Furthermore, microwaves caused increase in apoptosis rate (detected using Annexin V-FITC/PI kit) and reduced proliferative capacity of thymocytes (induced by ConA). However, melatonin caused decrease in alkaline and acid DNase activity, decrease in apoptotic rate and increase in proliferation rate of thymocytes. Melatonin exerts protective effects on rat thymocytes by modulating processes of apoptosis and proliferation, and causes decrease in DNA fragmentation and oxidative stress intensity under exposure to microwaves.

The effect of ursodeoxycholic acid on oxidative stress level and DNase activity in rat liver after bile duct ligation.

Accumulation of hydrophobic bile acids (BAs) during cholestasis plays an important role in apoptosis initiation as well as oxidative stress increase in liver cells. Ursodeoxycholic acid (UDCA) acts as a protector in BA-induced cell injury.The aim of the study was to evaluate the effect of UDCA on oxidative stress level and DNase I and II activity caused by liver injury in bile duct ligation (BDL) rats.Wistar rats were divided in four groups: group 1, control (sham-operated); group 2, sham-operated and injected with UDCA (30 mg/kg); group 3,animals with BDL; and group 4,UDCA-treatedcholestatic rats. Animals were sacrificed after 9 days. Malondialdehyde (MDA; lipid peroxidation end-product) level and protein-molecule oxidative modification (carbonyl group content) significantly increased in BDL rat liver. Catalase (CAT) activity in liver tissue was found to be decreased in BDL rats. In addition, xanthine oxidase (XO) activity, which is thought to be one of the key enzymes producing reactive oxygen species, was found to be increased in the cholestatic group. The apoptotic effect in cholestasis was probably triggered by the increased activation of DNase I and II. The protective effect of UDCA on liver tissue damage in BDL rats, in comparison to cholestatic liver, were 1) decrease of MDA levels, 2) increased CAT activity, 3) reduced XO activity, and 4) effect on terminal apoptotic reaction, shown as a decrease in DNase I and II activity.Therefore, UDCA may be useful in the preservation of liver function in cholestasis treatment.

Alkaline phosphatase activity in human colostrum as a valuable predictive biomarker for lactational mastitis in nursing mothers.

AIMS: Biochemical investigations have shown that an indigenous milk enzyme - alkaline phosphatase (ALP) - which is detectable in the lactocytes, plays a very important diagnostic role in clinical medicine, since its activity varies in different tissues and serves as a specific indicator of disease states. The purpose of this study was to evaluate ALP activity in human colostrum as a possible early predictive biomarker for lactational mastitis in nursing mothers. PATIENTS & METHODS: During a period from May to July 2010, a total of 60 healthy nursing mothers were recruited for this study. RESULTS: The mean level of colostrum ALP activity from the affected breasts was significantly higher when compared with ALP activity from the contralateral asymptomatic as well as 'healthy' breasts (p < 0.01). CONCLUSION: Determining ALP activity in colostrum could be a valuable biochemical marker for an early prediction of mastitis in nursing mothers.