Intervention of α-lipoic acid ameliorates methotrexate-induced oxidative stress and genotoxicity: A study in rat intestine

Methotrexate (MTX) is an anti-metabolite, widely used in the cancer chemotherapy and rheumatoid arthritis. However, its long-term clinical use is restricted on account of its severe intestinal toxicity. The present study was aimed to investigate the intestinal toxicity of MTX and the possible protective effect of α-lipoic acid (LA) on Sprague–Dawley rats. MTX-induced intestinal toxicity was evaluated at the dose of 2.5 mg/kg for short-term (5 days treatment) and 1 mg/kg for long-term (5 days in a week for four consecutive weeks treatment) study. The possible protective effect of LA was evaluated in both short- as well as long-term study in a dose-dependent manner. MTX treatment induced diarrhoea and mortality in rats, indicating its severe toxicity in the target organ of investigation, i.e., intestine. Further, the intestinal toxicity of MTX was assessed by evaluating different parameters of oxidative stress, DNA damage, cytotoxicity as well as histological changes. Immunostaining for p53 revealed higher genotoxic assault in the intestinal cells due to MTX treatment. Pretreatment of rats with LA led to significant decrease in the oxidative stress, DNA damage, cellular damage, inflammatory changes and apoptosis as determined by malondialdehyde level, glutathione level, comet assay parameters, histological evaluation, immunostaining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. In the present investigation, we report that LA pretreatment ameliorates MTX-induced intestinal toxicity in rat as evident from the protection against oxidative stress, decrease in DNA damage and protection of cellular morphology as well as improvement in the stool consistency and animal survival rate.     

Antagonistic Activity of Cellular Components of Potential Probiotic Bacteria, Isolated from the Gut of Labeo rohita, Against Aeromonas hydrophila

The objective of this study was to characterise the antagonistic activity of cellular components of potential probiotic bacteria isolated from the gut of healthy rohu (Labeo rohita), a tropical freshwater fish, against the fish pathogen, Aeromonas hydrophila. Three potential probiotic strains (referred to as R1, R2, and R5) were screened using a well diffusion, and their antagonistic activity against A. hydrophila was determined. Biochemical tests and 16S rRNA gene analysis confirmed that R1, R2, and R5 were Lactobacillus plantarum VSG3, Pseudomonas aeruginosa VSG2, and Bacillus subtilis VSG1, respectively. Four different fractions of cellular components (i.e. the whole-cell product, heat-killed whole-cell product [HKWCP], intracellular product [ICP], and extracellular product) of these selected strains were effective in an in vitro sensitivity test against 6 A. hydrophila strains. Among the cellular components, the ICP of R1, HKWCP of R2, and ICP of R5 exhibited the strongest antagonistic activities, as evidenced by their inhibition zones. The antimicrobial compounds from these selected cellular components were partially purified by thin-layer and high-performance liquid chromatography, and their properties were analysed. The ranges of pH stability of the purified compounds were wide (3.0–10.0), and compounds were thermally stable up to 90 °C. Considering these results, isolated probiotic strains may find potential applications in the prevention and treatment of aquatic aeromonosis.     

Sodium Salicylate Reduced Insulin Resistance in the Retina of a Type 2 Diabetic Rat Model

Sodium salicylate has been reported to reduce markers of diabetic retinopathy in a type 1 rat model. Because rates of type 2 diabetes are on the rise, we wanted to determine whether salicylate could improve insulin resistance in a type 2 rat model, as well as improve retinal function. We treated lean and obese BBZDR/Wor type 2 diabetic rats with salicylate in their chow for 2 months. Prior to salicylate treatment, rats underwent an electroretinogram to measure retinal function. After 2 months of treatment, rats underwent an additional electroretinogram prior to sacrifice. In addition to the animal model, we also treated retinal endothelial cells (REC) and rat Müller cells with salicylate and performed the same analyses as done for the rat retinal lysates. To investigate the role of salicylate in insulin signaling, we measured TNFα and caspase 3 levels by ELISA, as well as performed Western blotting for insulin receptor substrate 1, insulin receptor, SOCS3, and pro- and anti-apoptotic markers. Data demonstrated that salicylate significantly improved retinal function, as well as reduced TNFα and SOCS3-induced insulin resistance in all samples. Overall, results suggest that salicylate is effective in reducing insulin resistance in the retina of type 2 diabetic rat models.     

The band 3-rich membrane of llama erythrocytes: Studies on cell shape and the organization of membrane proteins

The erythrocyte membrane of the llama was characterized in comparison to that of the human. The llama erythrocyte was an elliptical disk that resisted shape alterations in hyperosmotic buffers and following metabolic depletion, both of which induce speculation of the human red cell. Lysophosphatidylcholine incorporation produced minor serrations of the edge of the llama disk but no spicules, whereas human red cells became sphero-echinocytes. The polypeptide profiles in the membranes of the two species were similar, except for several noteworthy differences: a marked elevation in the relative content of band 3; the absence of membrane-bound band 6; and simpler glycoprotein pattern in the llama. The concentration of band 3 in llama was about two and a half to three times that in the human and intramembrane particles in the protoplasmic leaflet of freeze-fractured llama membrane were correspondingly increased. The selective solubilization of bands 1, 2 and 5 in low ionic strength buffer, and all of the peripheral proteins in high alkaline buffer were similar except for increased retention of ankyrin by the llama membrane. These data suggest a similar disposition of membrane proteins. The llama membrane was markedly resistant to the solubilization of integral proteins by the nonionic detergent, Triton X-100. This property and the general resistance to shape changes may be related to the high concentration of band 3.     

Stock structure analysis of Labeo rohita (Hamilton, 1822) across the Ganga basin (India) using a truss network system

In this study the intraspecific variation of wild Labeo rohita was investigated on the basis of morphometric characters using the truss network system constructed from the fish body. Altogether 435 fish samples were collected from six drainages of the Ganga basin in India. Data were subjected to principal component analysis, discriminant function analysis and univariate analysis of variance. The first principal component (PC1) explained 47.88% of the total variation, while PC2 and PC3 explained 17.22 and 8.33%, respectively. The step‐wise discriminant function analysis retained three variables that significantly discriminated the populations. Using these variables, 62.3% of the original groups were classified into their correct samples and 53.1% of the cross‐validated groups omitting one procedure were classified into their correct samples. Misclassification was higher for samples from the River Gomti (28.6%). Of the total of 31 transformed truss measurements, 30 exhibited significant differences among populations. These findings indicate the presence of six different stocks of L. rohita in the Ganga basin.     

Adaptive coloration, behavior and predation vulnerability in three juvenile north Pacific flatfishes

Adaptive color change in flatfish has long been of interest to scientists, yet rarely studied from an ecological perspective. Because color change can take a day or so in some species, movement between sediments with differing color or texture may render fish more conspicuous to predators. We conducted laboratory experiments to test the following hypotheses related to adaptive color change in flatfish: 1) fish which do not cryptically match sediment will be more vulnerable to predation, 2) fish will reduce activity and bury to minimize conspicuousness when on a sediment they mismatch, and 3) fish will choose a sediment they match when given a choice. Experiments were conducted using three co-occurring north Pacific juvenile flatfishes: English sole Parophrys vetulus, northern rock sole Lepidopsetta polyxystra and Pacific halibut Hippoglossus stenolepis. As per expectations, juvenile flatfish were more vulnerable to visual predators when they mismatched sediment. Mismatched fish tended to behave differently than fish which matched the sediment. Rather than burying and becoming inactive, they became more active and less likely to bury, perhaps contributing to their predation vulnerability. This increased activity may have represented search for better matching sediment, a stress response, or conspicuousness-related density dependent behavior. Fish which had acclimated to light colored sediment preferred light over dark sediment in choice trials. In contrast, fish acclimated to dark sediment demonstrated no preference. These experiments demonstrate that adaptive coloration is an integral part of the flatfish detection minimization strategy and that movement between habitats can increase risk of predation.     

Retinal endothelial cell apoptosis

Retinal endothelial cell (REC) apoptosis occurs in response to a number of stressors, including high glucose, oxidative stress, hypoxia. Because these stressors are common factors in a number of ocular diseases, it is critical to understand the cellular mechanisms by which apoptosis occurs in REC. This review discusses the various models of REC used in ophthalmological research. The mechanisms responsible for REC apoptosis are discussed, as well as potential therapeutics currently under development to prevent REC apoptosis. The primary goal of this review is provide the reader with a background knowledge of the current state of research ongoing in REC apoptosis and potential avenues for future testing.