Agents In Experimental Models Research Articles

Methotrexate induced nephrotoxicity: possible underlying mechanisms and promising natural protective agents in experimental models

Methotrexate induced nephrotoxicity: possible underlying mechanisms and promising natural protective agents in experimental models

Emerging Roles of Cannabinoids and Synthetic Cannabinoids in Clinical Experimental Models.

In recent years, an increasing number of investigations has demonstrated the therapeutic potential of molecules targeting the endocannabinoid system. Cannabinoids of endogenous, phytogenic, and synthetic nature have been assessed in a wide variety of disease models ranging from neurological to metabolic disorders. Even though very few compounds of this type have already reached the market, numerous preclinical and clinical studies suggest that cannabinoids are suitable drugs for the clinical management of diverse pathologies.In this chapter, we will provide an overview of the endocannabinoid system under certain physiopathological conditions, with a focus on neurological, oncologic, and metabolic disorders. Cannabinoids evaluated as potential therapeutic agents in experimental models with an emphasis in the most successful chemical entities and their perspectives towards the clinic will be discussed.

The anti-adhesive effect of anti-VEGF agents in experimental models: A systematic review.

Adhesions constitute a major problem in abdominal-pelvic and thoracic surgery with significant impact in the postoperative quality of life and healthcare services utilization. Adhesiogenesis is the result of increased fibrin formation, impaired fibrinolysis, angiogenesis, and fibrosis. Despite the recent advancements, the ideal anti-adhesive agent remains to be determined. To this end, we performed a comprehensive literature search in PubMed, EMBASE, and Scopus databases to identify studies investigating the antiadhesive role of anti-VEGF agents in peritoneal, pleural, and pericardial experimental adhesion models. Fifteen studies were eligible for inclusion with a total population of 602 animals (334 rats, 180 rabbits, and 88 mice). The majority of included studies (11/15) used bevacizumab, while three studies used other anti-VEGF antibodies and one study used an anti-VEGFR-antibody. A rat model was used in nine studies, while rabbit (n = 3) or mouse (n = 3) models were used less frequently. Eleven studies used peritoneal models, three studies used pleural models, and one study used a pericardial model. The scales (n = 12) and interval (Range: 1-42 days) used for the evaluation of adhesions varied between the studies. All studies demonstrated a significant decrease in adhesion scores between the anti-VEGF and control groups up to 42 days postprocedure. VEGF blockade resulted in decreased fibrosis in four out of five studies that used peritoneal models, while the effect on pleural models depended on the pleurodesis agent and was significant between 7 and 28 days. The effect of anti-VEGF agents on anastomosis integrity depends on the dose and the model that is used (inconclusive results).Current data support the anti-adhesive role of Anti-VEGF agents in all three serosal surfaces up to 6 weeks postprocedure. Further studies are needed to confirm the anti-adhesive role of anti-VEGF agents in pleural and pericardial adhesion experimental models and investigate any effect on anastomosis integrity in peritoneal models.

Chemopreventive efficacy zingerone (4-[4-hydroxy-3-methylphenyl] butan-2-one) in experimental colon carcinogenesis in Wistar rats.

Colorectal cancer is one of the most common cancers worldwide. Development of naturally occurring inexpensive and safe alternatives can be effective in suppressing colon related proliferations. Zingerone (4-[4-hydroxy-3-methylphenyl] butan-2-one), a polyphenolic alkanone of ginger, has massive pharmacological properties and thus can be used as promising candidate against various ailments. In the current study, we aimed at demonstrating the protective effect of zingerone against experimental colon carcinogenesis and elucidating its possible mechanism by studying inflammatory and Nrf-2 signaling cascade. Four groups of animals (I-IV) were made with six animals each. Group I (control) was given normal saline orally. Group II was given 1,2-dimethylhydrazine (DMH) at the dose rate of 20 mg/kg body weight. Group III and IV were treated with DMH at the dose rate of 20 mg/kg body weight and also received oral treatment of zingerone at a dose rate of 50 and 100 mg/kg body weight, respectively, for first 5 weeks and animals were euthanized after 16 weeks. Our results reveal that DMH treated rats exhibited elevated ROS and MDA levels, increased activity of cytochrome P450 2E1 and serum marker enzyme carcinoembreyonic antigen (CEA), increased no of aberrant crypts of foci (ACF), and elevated expression of inflammatory and proliferative proteins. Nrf-2 was downregulated by DMH treatment. Treatment with zingerone to DMH treated rats, resulted in alterations in the activity of the cytochrome P450 2E1 and CEA. In addition, immunostaining of NF-kB-p65, COX-2, iNOS, and PCNA, Ki-67 was suppressed by zingerone. Furthermore, zingerone administration also attenuated the level of IL-6 and TNF-α and it also helps in preserving mucous layer. Thus, zingerone could be considered as a good chemopreventive agent in experimental model of colon carcinogenesis. Further studies are required to study other pathways involved in colon carcinogenesis and their modulation buy zingerone.

Germ cell apoptosis and survival in testicular inflammation.

Male infertility is due to genetics, hormonal or environmental causes, or is idiopathic. Azoospermia is linked to local testicular microenvironment deregulation, with inflammatory cells present in the 15% of testicular biopsies of infertile patients. As widely reported, spermatogenesis and steroidogenesis are controlled by local immunoregulatory agents produced by immune and nonimmune cells. Moreover IL-6R, TNFR1, Fas and IL-1R are expressed on germ cells, indicating a direct action of pro-inflammatory agents on these cells. Beyond the known function of cytokines and nitric oxide on testicular function at the stable levels present in the normal testis, this review focalises on the effect of pro-inflammatory factors on germ cell survival and death when inflammatory conditions are established in the testis. As no cure for male infertility has been found up to the present, intracytoplasmic sperm injection is the therapeutic option for azoospermic patients who wish to achieve genetic parenthood. Therapies with antioxidant and anti-inflammatory agents in experimental models of testicular damage have been successful. However, clinical implementation is uncertain in cases with a prolonged inflammatory state of the testis. Therapies offering multiple approaches to treat infertility by restoring the spermatogonial stem cell niche and protecting germ cells from apoptosis should be considered.

Antidotal effects of thymoquinone against neurotoxic agents.

Several plants which contain the active component thymoquinone (TQ) have been traditionally used in herbal medicine to treat various diseases. Several studies indicated the protective effects of TQ against neurotoxic agents. The present study was aimed to highlight the protective effects of TQ against neurotoxic agents. For this reason, the literature from 1998 to 2017 regarding the protective effects of TQ against neurotoxic agents and their involvement mechanisms has been studied. The present review suggests the protective effects of TQ against neurotoxic agents in experimental models. More clinical trial studies are however needed to confirm the antidotal effects of TQ in human intoxication.

Cellular pharmacology studies of anticancer agents: recommendations from the EORTC-PAMM group.

An increasing number of manuscripts focus on the in vitro evaluation of established and novel anti-tumor agents in experimental models. Whilst the design of such in vitro assays is inherently flexible, some of these studies lack the minimum information necessary to critically evaluate their relevance or have been carried out under unsuitable conditions. The use of appropriate and robust methods and experimental design has important implications for generating results that are reliable, relevant, and reproducible. The Pharmacology and Molecular Mechanisms (PAMM) group of the European Organization for Research and Treatment of Cancer (EORTC) is the largest group of academic scientists working on drug development and bundle decades of expertise in this field. This position paper addresses all researchers with an interest in the preclinical and cellular pharmacology of anti-tumor agents and aims at generating basic recommendations for the correct use of compounds to be tested for anti-tumor activity using a range of preclinical cellular models of cancer.

Camellia Sinensis Modulates Telomerase in Collagen-Induced Arthritis

Background: Rheumatoid arthritis is a chronic inflammatory disease with undefined pathogenesis. Some evidence suggests that telomerase is involved in the pathogenesis of this disease. This study was done to evaluate the therapeutic potency of Camellia sinensis stew (CSS) which rich in polyphenolic compounds with anti-inflammatory properties in experimental model of rheumatoid arthritis. Methods: In this experimental study, collagen-induced arthritis (CIA) was induced by immunization of Lewis rats. The paws and knees were then removed for histopathology analysis. Moreover, Roentgenogram analysis of normal and arthritic hind paws was performed. Synovial cell harvested from biopsies of synovial tissue were used for measuring telomerase activity. The results were analyzed using SPSS version 16 software. Results: Our data showed that CSS induced a significant reduction in paw edema. Histopathological findings showed reduced inflammatory responses and bone erosion in joints of treated rats. Moreover, CSS showed a significant reduction of telomerase activity compares with control group. Conclusions: Our findings revealed that CSS should be considered as a therapeutic agent in experimental model of rheumatoid arthritis based on its telomerase activity suppression.

Anti-inflammatory effect of birsonimadiol from seeds of Byrsonima crassifolia.

The new compound identified as 16α,23α-dihydroxy-3β,28β,30α-triacetoxy-olean-12-ene, named birsonimadiol (BIR) was isolated from Byrsonima crassifolia seeds using activity-guided fractionation and structural elucidation was achieved based on extensive analysis of spectroscopic data. Effects of BIR on acute and chronic phases of inflamation were studied in edema induced using formaldehyde, 12-O-tetradecanoylphorbol-acetate (TPA)-induced ear edema (meloperoxidase activity), and histamine, carrageenan, cotton pellet granuloma, and adjuvant-induced arthritis. Anti-inflammatory activities of BIR were indicated based on reduction of edema levels induced in models of inflammation. Anti-inflammatory activities were also investigated in murine macrophage RAW264.7 cells. BIR suppressed production of nitric oxide (NO) and prostaglandin E2 (PGE2), decreased gene expression of cyclooxygenase-2 (COX-2), inhibited tumor necrosis factor (TNF)-α, and protein secretion of interleukin IL-6. Triterpene was an effective topical anti-inflammatory agent in experimental models of acute and chronic dermatitis and can be used in inflammatory disorders.

Synergy between surface and core entrapped metals in a mixed manganese–gadolinium nanocolloid affords safer MR imaging of sparse biomarkers

High-relaxivity T1-weighted (T1w) MR molecular imaging nanoparticles typically present high surface gadolinium payloads that can elicit significant acute complement activation (CA). The objective of this research was to develop a high T1w contrast nanoparticle with improved safety. We report the development, optimization, and characterization of a gadolinium–manganese hybrid nanocolloid (MnOL-Gd NC; 138±10 (Dav)/nm; PDI: 0.06; zeta: −27±2mV). High r1 particulate relaxivity with minute additions of Gd-DOTA-lipid conjugate to the MnOL nanocolloid surface achieved an unexpected paramagnetic synergism. This hybrid MnOL-Gd NC provided optimal MR TSE signal intensity at 5nM/voxel and lower levels consistent with the level expression anticipated for sparse biomarkers, such as neovascular integrins. MnOL NC produced optimal MR TSE signal intensity at 10nM/voxel concentrations and above. Importantly, MnOL-Gd NC avoided acute CA in vitro and in vivo while retaining minimal transmetallation risk. From the Clinical EditorThe authors developed a gadolinium-manganese hybrid nanocolloid (MnOL-Gd NC) in this study. These were used as a high-relaxivity paramagnetic MR molecular imaging agent in experimental models. It was shown that MnOL-Gd NC could provide high T1w MR contrast for targeted imaging. As the level of gadolinium used was reduced, there was also reduced risk of systemic side effects from complement activation.

Oleanolic acid: a promising neuroprotective agent for cerebral ischemia.

Oleanolic acid: a promising neuroprotective agent for cerebral ischemia.

N-Acetyl-Serotonin Offers Neuroprotection through Inhibiting Mitochondrial Death Pathways and Autophagic Activation in Experimental Models of Ischemic Injury

N-acetylserotonin (NAS) is an immediate precursor of melatonin, which we have reported is neuroprotective against ischemic injury. Here we test whether NAS is a potential neuroprotective agent in experimental models of ischemic injury. We demonstrate that NAS inhibits cell death induced by oxygen-glucose deprivation or H2O2 in primary cerebrocortical neurons and primary hippocampal neurons in vitro, and organotypic hippocampal slice cultures ex vivo and reduces hypoxia/ischemia injury in the middle cerebral artery occlusion mouse model of cerebral ischemia in vivo. We find that NAS is neuroprotective by inhibiting the mitochondrial cell death pathway and the autophagic cell death pathway. The neuroprotective effects of NAS may result from the influence of mitochondrial permeability transition pore opening, mitochondrial fragmentation, and inhibition of the subsequent release of apoptogenic factors cytochrome c, Smac, and apoptosis-inducing factor from mitochondria to cytoplasm, and activation of caspase-3, -9, as well as the suppression of the activation of autophagy under stress conditions by increasing LC3-II and Beclin-1 levels and decreasing p62 level. However, NAS, unlike melatonin, does not provide neuroprotection through the activation of melatonin receptor 1A. We demonstrate that NAS reaches the brain subsequent to intraperitoneal injection using liquid chromatography/mass spectrometry analysis. Given that it occurs naturally and has low toxicity, NAS, like melatonin, has potential as a novel therapy for ischemic injury.

Comparative Study of the Optical and Heat Generation Properties of IR820 and Indocyanine Green

AbstractNear-infrared (NIR) fluorophores are the focus of extensive research for combined molecular imaging and hyperthermia. In this study, we showed that the cyanine dye IR820 has optical and thermal generation properties similar to those of indocyanine green (ICG) but with improved in vitro and in vivo stability. The fluorescent emission of IR820 has a lower quantum yield than ICG but less dependence of the emission peak location on concentration. IR820 demonstrated degradation half-times approximately double those of ICG under all temperature and light conditions in aqueous solution. In hyperthermia applications, IR820 generated lower peak temperatures than ICG (4-9%) after 3-minute laser exposure. However, there was no significant difference in hyperthermia cytotoxicity, with both dyes causing significant cell growth inhibition at concentrations ≥ 5 μM. Fluorescent images of cells with 10 μM IR820 were similar to ICG images. In rats, IR820 resulted in a significantly more intense fluorescence signal and significantly higher organ dye content than for ICG 24 hours after intravenous dye administration (p < .05). Our study shows that IR820 is a feasible agent in experimental models of imaging and hyperthermia and could be an alternative to ICG when greater stability, longer image collection times, or more predictable peak locations are desirable.

Atorvastatin and simvastatin as analgesic agents in experimental models.

Objectives:1) To evaluate the analgesic effect of atorvastatin and simvastatin. 2) To compare analgesic activity of these with an established drug tramadol.Materials and Methods:Healthy Albino rats were taken. They were randomly divided into 4 groups of six animals each. Group I: Normal Saline (0.5 ml), Group II: Tramadol (10 mg/kg BW), Group III: Atorvastatin (10 mg/kg BW) and Group IV: Simvastatin (10 mg/kg BW). The animals were subjected to 3 different tests at different interval of time. The tests conducted were tail clip method, Eddy′s hot plate and hot water tail immersion method.Results:Atorvastatin and simvastatin differ significantly from control hence they have analgesic action and even at any of the time intervals they do not differ significantly from tramadol; hence their analgesic effect is nearly comparable to tramadol. The results of the present study indicate that atorvastatin and simvastatin have analgesic action.Conclusion:These statins are found to have analgesic effect other than hypolipidemic activity and can be used in these patients. However further study has to be undertaken in a broader way.

Systemic administration of doxorubicin impairs aversively motivated memory in rats

There is growing clinical evidence of cognitive impairment in cancer patients treated with chemotherapy, especially in women treated with drug combinations for breast cancer. Clinical studies have a difficult task of defining which drugs individually are responsible for the cognitive changes and published papers evaluating single agents in experimental models are scanty. In the present study we have investigated the effect of single escalating doses of doxorubicin (DOX) on memory for inhibitory avoidance conditioning (IA) in rats. The doses used were comparable to those applied in the clinic. When given systemically before training, higher doses of DOX impaired IA memory retention measured 24 h and 7 days, but not 3 h after training. DOX did not affect IA retention when given either before or after training in a multiple-trial IA training protocol. Control experiments showed that DOX produced a decrease in exploratory behavior assessed by the number of rearings performed during exploration of an open field. The results indicate that a single systemic administration of DOX might impair long-term aversive learning.

Neuroprotective profile of dextromethorphan in an experimental model of penetrating ballistic-like brain injury

Dextromethorphan (DM) has been well-characterized as a neuroprotective agent in experimental models of CNS injury. The goal of this study was to determine the neuroprotective profile of DM in a military-relevant model of penetrating ballistic-like brain injury (PBBI). In an acute (3 day) dose–response study, anesthetized male Sprague–Dawley rats were exposed to a unilateral frontal PBBI with DM (0.156–10 mg/kg) or vehicle delivered as an i.v. bolus from 30 min to 48 h post-injury. In a follow-up (7 day) experiment, the 10-mg/kg bolus injections of DM were administered in conjunction with a 6-h infusion (5 mg/kg/h). DM bolus injections alone produced a dose-dependent improvement in motor recovery on a balance beam task at 3 days post-injury. However, more rapid recovery (24 h) was observed on this task when the bolus injections were combined with the 6-h infusion. Moreover, the DM bolus/infusion treatment regimen resulted in a significant (76%) improvement in cognitive performance in a novel object recognition (NOR) task at 7 days post-injury. Although post-injury administration of DM (all doses) failed to reduce core lesion size, the maximum dose of DM (10 mg/kg) was effective in reducing silver-stained axonal fiber degeneration in the cortical regions adjacent to the injury.

Immunomodulator FTY720 Induces Myofibroblast Differentiation via the Lysophospholipid Receptor S1P 3 and Smad3 Signaling

The novel immunomodulator FTY720 is an effective immunosuppressive agent in experimental models of transplantation and autoimmunity and is currently undergoing phase III clinical trials for multiple sclerosis. Phosphorylated FTY720 is a structural analogue of sphingosine 1-phosphate (S1P) and therefore acts as a high-affinity agonist at four of the five G protein-coupled S1P receptors. It has been well established that there exists a crosstalk between S1P and transforming growth factor (TGF)-beta signaling. Because TGF-beta is the most prominent inductor of fibrosis and myofibroblasts are primarily responsible for excessive matrix protein formation, we examined whether FTY720, in analogy to TGF-beta, induces differentiation of fibroblasts into myofibroblasts. Indeed, FTY720 provoked myofibroblast differentiation comparable with that of TGF-beta. For biological efficacy, FTY720 required endogenous phosphorylation because inhibition of sphingosine kinase completely prevented FTY720 from inducing the differentiation process. Moreover, we identified the lysophospholipid receptor S1P3 as the crucial receptor subtype for FTY720-induced myofibroblast differentiation because the effect was abolished in fibroblasts isolated from S1P3 knockout mice. Finally, we determined that downstream of S1P3 signaling Smad3 activation is essential for myofibroblast differentiation in response to FTY720. Thus, FTY720 may have adverse fibrotic effects related to its activity on S1P3 signaling.

WAY-202196, a selective estrogen receptor-beta agonist, protects against death in experimental septic shock

To determine the effect of an estrogen receptor-beta selective agent in experimental models of systemic infection and sepsis. WAY-202196, a nonsteroidal selective estrogen receptor-beta agonist, was tested in the murine listeriosis model, the neutropenic rat Pseudomonas aeruginosa infection, and the mouse cecal ligation and puncture sepsis models. University-affiliated biomedical research laboratory. BALB/c mice and Sprague-Dawley rats. WAY-202196 or control (vehicle) was administered orally in doses ranging from 1.5 to 50 mg/kg at various time points in the three experimental model systems. Susceptibility of mice treated with a single oral dose of up to 50 mg/kg WAY-202196 did not differ from those treated with vehicle alone after systemic challenge by Listeria monocytogenes, suggesting a lack of generalized immunosuppression. In the neutropenic rat model, daily administration of WAY-202196 (50 mg/kg) significantly increased survival against an otherwise lethal challenge of P. aeruginosa 12.4.4 compared with the control group (83% vs. 25% survival; p < 0.05). Preservation of intestinal mucosal weight and prevention of histopathologic changes were also observed with the administration of WAY-202196. Similar results were obtained in a cecal ligation and puncture model, in which multiple oral doses of WAY-202196 (50 mg/kg) improved survival (83% vs. 0%; p < 0.05), preserved intestinal epithelial integrity, and significantly reduced systemic bacteremia and peritoneal interleukin-6 and tumor necrosis factor levels. The estrogen receptor-beta agonist provided a comparable level of protection in both male and female animals. These results indicate that oral administration of WAY-202196 preserved gastrointestinal barrier function and improved outcome in experimental models of systemic infection and inflammation. WAY-202196 and similar agents may prove useful clinically as a novel treatment strategy for the treatment or prevention of severe sepsis.

Fenofibrate induces plaque regression in hypercholesterolemic atherosclerotic rabbits: In vivo demonstration by high-resolution MRI

Introduction Fenofibrate has shown to reduce major cardiovascular events and slow angiographic progression of coronary atherosclerosis. The postulated mechanism of action is via the activation of peroxisomal proliferator-activated receptor-α (PPAR-α), a nuclear transcription factor that controls a variety of cellular functions. We investigated the anti-atherogenic effects of fenofibrate on previously established experimental atherosclerotic lesions. Method Atherosclerotic lesions were induced in the abdominal aorta of New Zealand white (NZW) rabbits ( n = 19) by a combination of a double-balloon injury and a 9-month hypercholesterolemic diet. The rabbits were randomized into placebo or fenofibrate group. The corresponding treatments were added to the hypercholesterolemic diet. All rabbits underwent MRI examination at randomization and after 6 months of treatment, and were then sacrificed for histopathology. Results LDL-cholesterol was similarly elevated at randomization and follow-up, and was not significantly modified by fenofibrate therapy. HDL-cholesterol decreased (−27 ± 10%, p = 0.04) in the placebo and increased (+36.8 ± 2%, p = 0.04) in the fenofibrate group. MRI showed comparable vessel wall area (VWA) at randomization in both groups. At 15 months, a significant increase in VWA was seen in the placebo group (15 ± 4%, p = 0.007), while fenofibrate treatment was associated with a regression (−11 ± 4%, p = 0.041) of previously established lesions. Fenofibrate also decreased macrophage and increased smooth muscle cell/collagen content of atherosclerotic lesions. Conclusion MRI measurements can, in conjunction with in vitro histological measurements, contribute to the understanding of the actions of pharmacologic agents in experimental models of atherosclerosis. Fenofibrate significantly regresses atherosclerotic lesions and induced changes in plaque composition associated with a more “stable” phenotype (reduced macrophages and increased SMC). These observations support the potential anti-atherogenic effects of PPAR-α agonists.

Characterization of a recombinant adenovirus vector encoding heat-inducible feline interleukin-12 for use in hyperthermia-induced gene-therapy

Interleukin-12 (IL-12) is a pro-inflammatory cytokine that has shown great promise as a therapeutic agent in experimental models of infectious disease and cancer. However, it is also a highly toxic molecule and for that reason has not been accepted readily into the clinic. A replication-deficient adenoviral vector was designed to deliver the feline interleukin-12 gene into tumour cells. The interleukin-12 gene has been placed under control of a heat inducible promoter, human heat shock promoter 70b, with the intent of spatially and temporally controlling the expression of IL-12, thus limiting its toxicity. In vitro, the transfection efficiency of the adenoviral vector, the effect of multiplicity of infection and the production of biologically active feline IL-12 were studied in the infected cells in response to a range of temperatures. This adenoviral vector will be a useful tool to examine the effects of intra-tumoural IL-12 delivery in a spontaneously occurring feline soft tissue sarcoma model.