Effects of the ascorbic acid supplementation on NADH-diaphorase myenteric neurons in the duodenum of diabetic rats.

We assessed the ascorbic acid (AA) supplementation on the myenteric neurons in the duodenum of rats. Fifteen rats with 90 days of age were divided into three groups: control (C), diabetics (D) and ascorbic acid treated diabetics (DA). After 120 days of daily treatment with AA, the duodenum was submitted to the NADH-diaphorase (NADH-d) histochemical technique, which allowed us to evaluate the neuronal density in an area of 8.96 mm2 for each duodenum, and also to measure the cellular profile area of 500 neurons per group. The supplementation promoted an increase on AA levels. The neuronal density (p < 0.05) was higher in the group DA when compared to group D. There were no significant differences in the neuronal areas, when we compared groups C (204 +/- 16.5) and D (146.3 +/- 35.84) to groups D and DA (184.5 +/- 5.6) (p > 0.05). The AA-supplementation avoided the density reduction of the NADHd myenteric neurons in the duodenum of diabetic rats.     

Cyclosporine improves remyelination in diabetic rats submitted to a gliotoxic demyelinating model in the brainstem

The use of cyclosporine (CsA) has shown to induce an increase in density of oligodendrocytes near remyelinating areas following the injection of ethidium bromide (EB), a demyelinating agent, in the rat brainstem. It is also known that diabetes mellitus was capable of delaying remyelination by both oligodendrocytes and Schwann cells in this gliotoxic model. This study was designed to assess whether CsA had the capacity to improve remyelination in streptozotocin‐induced (50 mg/kg, intraperitoneal route) diabetic rats. Diabetic Wistar rats were divided in different groups receiving 10 microlitres of 0.1% EB or 0.9% saline solution into the cisterna pontis and were treated or not with CsA. During 7 days and, thereafter, three times a week, 10 mg/kg/day of CsA were given by intraperitoneal route. The rats were euthanized from 7 to 31 days after EB or saline injection and brainstem sections were collected and processed for light and transmission electron microscopy studies. Results from different groups were compared by using a semi‐quantitative method developed for documenting the extent and nature of remyelination in semithin sections following gliotoxic lesions. Results showed that CsA administration to diabetic rats after EB injection stimulate both oligodendroglial and Schwann cell remyelination (mean remyelination scores of 3.15 ± 0.5 for oligodendrocytes and 1.36 ± 0.58 for Schwann cells) compared to untreated animals (2.52 ± 0.71 for oligodendrocytes and 0.73 ± 0.47 for Schwann cells, respectively). CsA given to diabetic rats was capable of reversing some of the deleterial effects of diabetes on remyelination. Microsc. Res. Tech. 76:714–722, 2013. © 2013 Wiley Periodicals, Inc.     

Structural arrangement of the cardiac collagen fibers of healthy and diabetic dogs

The heart is composed by a specialized muscle, whose form and function are essentials for an adequate work and shows an amount of connective tissue which support and provide insertion for this muscle, whose collagen fibers are responsible for determination of tissue feature. Our objective was to identify the structural arrangement of the heart collagen fibers in dogs. The hearts of the dogs were submitted to the process of the controlled digestion with NaOH solution and observed by scanning electron microscope. Our results showed that the collagen fibers of the endomysial wall have structural arrangement composed by an irregular network with one layer in normal dogs but in diabetic dogs the network acquires a greater amount of the fibers and layers, looking like a "rug" of fibers modifying the relationships of the stress/strain of the tissue. Ahead of the observed results we are able to conclude that exist increase in the amount and thickness of cardiac collagen fibers, beyond the increase of layers and architectural disarrangement in the endomysial wall in the diabetic dogs.     

Morphological changes of poly(DI‐lactide‐co‐glycolide) nano‐particles containing ascorbic acid during in vitro degradation process

Poly(dl ‐lactide‐co‐glycolide) powder composed of uniform particles with the mean particle size in the range of 110–170 nm was obtained from commercial granules. Ascorbic acid in different concentrations was encapsulated into the poly(dl ‐lactide‐co‐glycolide) particles. Degradation of the latter in terms of morphological changes in the physiological solution was followed. Within a period of 2 months, the particles completely degrade and all the ascorbic acid is released. The samples were characterized by ultraviolet spectroscopy and scanning electron microscopy.     

Goblet cell number in the ileum of rats denervated during suckling and weaning.

The enteric nervous system plays a role on the stimulation of secretory cells of intestinal epithelia. We have demonstrated that ablation of ENS stimulates epithelial cell proliferation. As goblet cells are important constituents of the epithelial sheet, it is mandatory to investigate separately this cell type. The myenteric plexus of the ileum of rats in postnatal development was partially removed by the serosal application of benzalkonium chloride (BAC). Three groups of animals were used: those where BAC application was at 13 days and sacrifice was at 15 (13/28-day-old) or 23 days after treatment (13/36-day-old), and those where BAC was applied at 21 days and rats were killed 15 days after treatment (21/36-day-old) . The number of goblet cells in the ileum was estimated in sections stained by periodic acid-Schiff (PAS) histochemistry. In the 13/28 and 21/36 groups, the number of goblet cells was significantly higher after BAC treatment. These results suggest that the myenteric denervation may have an acute effect on the number of goblet cell in suckling and weanling rats, probably through submucous plexus.     

Combinatory effect of hesperetin and mesenchymal stem cells on the deteriorated lipid profile,heart and kidney functions and antioxidant activity in STZ-induced diabetic rats

This study aimed to assess the effect of hesperetin and/or bone marrow-derived mesenchymal stem cells(BM-MSCs) on disturbed lipid profile, heart and kidney functions, oxidative stress and antioxidant defense systemin streptozotocin (STZ)-induced diabetic rats. Type 1 diabetes mellitus (T1DM) was induced in male Wistar rats byinjecting 40 mg/kg body weight (b.w.) STZ dissolved in citrate buffer (pH 4.5). The diabetic rats were treated withhesperetin orally administered at dose 20 mg/kg b.w., BM-MSCs intravenously injected at a dose of 1 x 106 cells/rat/week and their combination for 6 weeks. The diabetic rats exhibited lipid abnormalities manifested by elevatedserum levels of total cholesterol, triglycerides, LDL-cholesterol and VLDL-cholesterol and lowered HDL-cholesterolas well as elevated liver cholesterol and triglycerides content in association with the resultant fasting and postprandialhyperglycemia and insulin deficiency. The heart function biomarkers including CK-MB, AST and LDH activities aswell as levels of kidney function parameters, creatinine, and urea, were significantly raised in the serum of diabeticrats. These changes were concomitant with abnormal redox balance represented by elevated lipid peroxidation,decreased glutathione content, and suppressed antioxidant enzyme activities in both heart and kidney of diabetic rats.The previous deleterious alterations were significantly ameliorated after the treatment of diabetic rats with hesperetinand BM-MSCs singly or in combination; the treatment with hesperetin together with BM-MSCs was the most potent.Based on these findings, it can be concluded that the use of hesperetin with BM-MSCs may have more additivetherapeutic value than their uses singly in T1DM. In addition, the ameliorative effects of hesperetin and BM-MSCson lipid profile and heart and kidney functions in diabetic rats may be mediated, at least in part, via their suppressiveeffects on oxidative stress and ameliorative effects on the antioxidant defense system secondary to improvement in thehyperglycemia and insulin secretory response.     

Advanced glycation end-products change placental barrier function and tight junction in rats with gestational diabetes mellitus via the receptor for advanced glycation end products/nuclear factor-κB pathway

The placenta plays an important role in nutrient transport to maintain the growth and development of theembryo. Gestational diabetes mellitus (GDM), the most common complication during pregnancy, highly affectsplacental function in late gestation. Advanced glycation end-products (AGEs), a complex and heterogeneous group ofcompounds engaged by the receptor for AGEs (RAGE), are closely associated with diabetes-related complications. Inthis study, AGEs induced a decrease in the expression of tight junction (TJ) proteins in BeWo cells and increased theparacellular permeability of trophoblast cells by regulating RAGE/NF-κB. Sprague-Dawley (SD) rats injected with100 mg/kg AGEs-rat serum albumin (RSA) via the tail vein from embryo day 2 were set as the placental barrierdysfunction model group (n = 10). The effect of AGEs on placental permeability was determined using the EvansBlue dye extravasation method. The ultrastructure of the placenta samples was observed by transmission electronmicroscopy. The effects of AGEs on the placenta were confirmed by treating rats with RAGE antagonist FPS-ZM1and soluble forms of RAGE (sRAGE). AGEs treatment increased placental permeability and disrupted the tightjunctions in pregnant rat placenta, but has no effect on blood glucose. The expression of TJ-related proteins,including ZO-1, Occludin, and Claudin 5, were downregulated after AGEs treatment. Further, AGEs treatmentincreased the expression of RAGE and nuclear factor-κB in the placenta of rats and upregulated the levels of vascularendothelial growth factor. The effects of AGEs on the placenta were blocked by RAGE antagonist FPS-ZM1 andsRAGE. This study demonstrates the mechanism underlying AGEs-induced disturbance in placental function inpregnant rats and highlights the potential of AGEs in the treatment of GDM.     

Ultrastructural changes in the ovary cells of engorged Rhipicephalus sanguineus female ticks treated with esters of ricinoleic acid from castor oil (Ricinus communis)

Rhipicephalus sanguineus is a widely distributed tick species that has adapted to the urban environment, and the dog is its main host. This species is also known as a vector and reservoir of diseases caused by bacteria, protozoa, and viruses. Currently, acaricides of synthetic chemical origin have been widely and indiscriminately used, leading to the development of resistance to these products by ticks and causing damage to the environment. Thus, these issues have made it necessary to seek other forms of controlling these ectoparasites. R. sanguineus was artificially infested in host New Zealand White rabbits, which were divided into four treatment groups: control (CG1 and CG2) and treatment (TG1 and TG2) groups. TG1 and TG2 hosts were provided with feed supplemented with esters of ricinoleic acid from castor oil at a concentration of 5 g/kg of feed for 7 and 15 days. Afterward, the ovaries of the female ticks were removed for analysis by transmission electron microscopy. The results showed ultrastructural changes in the somatic and germ cells of ovaries from TG1 and TG2 females, particularly with respect to chorion deposition, a protective membrane of the oocyte, as well as in the transport process of vitellogenic materials via the hemolymph and pedicel cells. Moreover, the mitochondria were less electron-dense and had cristae that were more disorganized than the mitochondria from CG1 and CG2 individuals. Thus, this study demonstrated the action of esters on the ovaries of R. sanguineus, signaling the prospect of a way to control this ectoparasite without affecting nontarget organisms or the environment.     

Dose–response and histopathological study,with special attention to the hypophysis,of the differential effects of domoic acid on rats and mice

The effects of the neurotoxin domoic acid (DA) in the central nervous system of rodents (essentially rats and mice) after intraperitoneal administration have been profusely studied in the past. These observations have shown that the toxin induces similar symptoms and pathology in both species, but the lethality varies greatly. This article addresses the common and specific histopathological effects in rats and mice and the difference in sensitivity of these species to DA. Various sublethal and lethal doses were employed in mice (from 3 mg/kg to 8 mg/kg) to observe their neurotoxicity by using different histological techniques, and these results were compared with the pathological effects after the administration of LD50 in rats (2.5 mg/kg). Additionally we also detected the presence of this toxin in various tissues by means of immunohistochemistry. Our results showed that rats are more vulnerable than mice to the neurotoxic effects of DA after intraperitoneal inoculation: lethality was extremely high in rats and the toxin produced hippocampal damage in rats surviving the intoxication, while lesions were not observed in DA‐inoculated mice. As for similarities between rats and mice, both displayed similar clinical signs and in both the toxin was detected in the hypophysis by immunohistochemistry, a brain region not reported to date as target of the toxin. Microsc. Res. Tech. 78:396–403, 2015. © 2015 Wiley Periodicals, Inc.     

Evaluation of testicular tissue of adult rats treated with cisplatin incorporated into the liposome

Cisplatin (CPL) is one of the most widely used and effective chemotherapeutic agents for the treatment of several human malignancies. However, it causes serious side effects, especially on reproduction. In order to reduce the undesirable effects caused by many drugs, liposomes have been used as a good system for drug delivery. The aim of this study was to investigate, for the first time, the effects of CPL incorporated into the dipalmitoyl phosphatidylcholine liposome (DPPC) on the testicular tissue of adult Wistar rats. The animals (n = 20) were distributed into four experimental groups: (a) control (distillated water); (b) liposome (DPPC, 1 mL), (c) cisplatin incorporated into liposome (CPL/DPPC), and (d) CPL (8 mg/kg body weight). The animals received a single intraperitoneal injection and were killed 10 days after each treatment for histopathological analysis of testes. The results showed that the testicular histomorphometric parameters in rats of DPPC and CPL/DPPC groups were similar to those of the control group. Meanwhile, rats of the CPL‐treated group showed a variety of morphological alterations, including atrophy of seminiferous tubules and presence of multinucleated cells in the germinal epithelium. The incorporation of CPL into the liposome had no influence on the testicular weight or any other stereological parameters, but it was beneficial in maintaining the body weight of the animals. In conclusion, the liposome suppressed the cytotoxic effects caused by cisplatin in the testes of rats, suggesting a possible use in chemotherapy against cancer to reduce the side effects seen on reproduction. Microsc. Res. Tech. 78:323–329, 2015. © 2015 Wiley Periodicals, Inc.     

Effect of dentin and fiber post surface treatments with fumaric acid on the bonding ability of fiber posts

This study investigated the effects of fumaric acid on push‐out bond strength when applied to dentin surfaces and fiber posts. The root canals of 60 mandibular premolar teeth were instrumented and obturated. After removing two thirds of filling material, teeth were prepared according to six randomized groups (n = 10/group) defined by two fiber post surface treatments (0.7% fumaric acid or 9% hydrofluoric acid) and three dentin conditioning treatments [control (no conditioning); 17% ethylenediamine tetraacetic acid (EDTA); or 0.7% fumaric acid]. After fiber post‐cementation, three 1‐mm thick discs were obtained from each tooth by transverse sectioning, and each disc underwent push‐out bond strength testing. Data were analyzed with a one‐way analyses of variance (anova ) and t tests; p < .05 was considered statistically significant. Failure modes were determined by stereomicroscopy, and the surface characteristics of dentin and fiber posts were observed by scanning electron microscopy. Push‐out bond strength was greater for the group in which the post surface treated with hydrofluoric acid and the dentin surface treated with fumaric acid than the nontreated dentin and hydrofluoric acid‐treated post group (p < .05). There were no significant differences between other comparison pairs (p > .05). A combination of fumaric acid dentin conditioning and hydrofluoric acid fiber post treatment strengthened the bonding ability of fiber posts.     

A comparative study on the performance of boric acid with several conventional lubricants in metal forming processes

During metal forming, lubricants are necessary to prevent direct contact, adhesion, transfer, and scuffing of workpiece materials and tools. The lubricating action of boric acid is due to its layered crystalline structure, and is similar to the structure of MoS₂ and graphite. However, boric acid lubrication could offer distinct advantages in terms of its application prior to forming and removal after a forming operation since it can be dispensed using water and alcohol solutions, raising the possibility of being environmentally friendly. Its effectiveness under actual conditions of metal forming operations such as rolling, forging, and sheet metal drawing and stretching has been evaluated in this study with both ferrous and non-ferrous work materials. It was found that boric acid provided lowest friction in sheet drawing and stretching operations, which is attributed to its lattice layer structure that facilitates easy sliding between molecular layers. Under predominantly compressive conditions of forming, liquid or semi-solid lubricants have performed better as they could squeeze out along with forwarding workpiece surfaces. The findings presented in this paper increase the prospect for developing boric acid as an effective lubricant in the cold forming of materials under certain conditions.     

Combined molecular docking,homology modeling and DFT method for the modification of bovine serum albumin (BSA) to improve fluorescence spectroscopy for phthalate acid esters chelated with BSA

While phthalate acid esters (PAEs) cannot fluoresce alone, they can be detected by fluorescence spectroscopyafter chelation with bovine serum albumin (BSA). In this study, the types of amino acid residues at the active site of PAEschelated with BSA were determined using molecular docking technology. A modification scheme of BSA with higherdetection sensitivity fluorescence spectroscopy for PAEs was proposed based on the docking results and constructedfor a novel BSA structure with a higher detection sensitivity of fluorescence spectroscopy using a homologousmodeling method. Density functional theory (DFT) was employed to explore the influence before and after BSAmodification on PAEs’ detection through fluorescence spectroscopy. The results showed that the docking scoresbetween BSAs and dimethyl phthalate (DMP), dibutyl phthalate (DBP) and di-n-octyl phthalate (DNOP) wereincreased up to 26.45%, 16.82% and 16.30%, respectively, indicating that the active site modification of BSA couldenhance the binding affinity between BSA and PAEs. The fluorescence intensity of PAEs chelated with modified BSAswere calculated. The fluorescence intensity of fluorescence spectroscopy for DMP, DBP and DNOP chelated withBSAs after modification was increased up to 2.8-, 104.51- and 62.43-fold, respectively, which achieved the purpose oftheoretically modifying BSA to improve the detection sensitivity of fluorescence spectroscopy for PAEs.