Sodium selenite ameliorates both intestinal and extra-intestinal changes in acetic acid-induced colitis in rats

Crosstalk between SIRT1/Nrf2 signaling and NLRP3 inflammasome/pyroptosis as a mechanistic approach for the neuroprotective effect of linagliptin in Parkinson's disease

In recent years, special attention has been paid to highlighting the antiparkinsonian effect of linagliptin. However, the mechanism of its action has not yet been well investigated. The present study aimed to verify the neuroprotective effect of linagliptin in the rotenone model of Parkinson's disease (PD) and further explore its potential molecular mechanisms. Rats were intoxicated with rotenone (2 mg/kg/day; sc) and treated with linagliptin (10  mg/kg/day; po) for 14 consecutive days. The present finding showed that linagliptin ameliorated the histopathological changes of rotenone on substantia nigra and striata. Linagliptin decreased α-synuclein immunoreactivity along with an increase in tyrosine hydroxylase immunoreactivity and striatal dopamine content. This was reflected in the marked improvement of the behavior and motor deficits in rotenone-intoxicated rats. On the molecular level, linagliptin upregulated sirtuin 1 (SIRT1)/ nuclear factor erythroid 2-related factor 2 (Nrf2) signaling, reduced ionized calcium-binding adaptor molecule 1 (Iba1) protein expression, restored glutathione (GSH) content, and elevated heme oxygenase-1 (HO-1) level in rats with rotenone intoxication. Moreover, linagliptin inhibited NOD-like receptor protein 3 (NLRP3)/caspase-1/interleukin-1β (IL-1β) cascade with subsequent reduction in gasdermin D (GSDMD) expression. Therefore, the present study reveals the ability of linagliptin, through the activation of SIRT1/Nrf2 signaling, to suppress NLRP3 inflammasome-mediated pyroptosis and protect against rotenone-induced parkinsonism.

Experimental colitis is comorbid with social interaction deficits and anxiety-like behaviors in mice: mechanistic intuitions into neuroinflammation and Claudin 5 expression in the hippocampus

Inflammatory bowel disease (IBD) is accompanied by psychiatric disorders, including Schizophrenic-like manifestations. Although incompletely illustrated, intestinal mucosal membrane damage and blood-brain barrier (BBB) penetrability may have significant roles in psychiatric symptoms of IBD. This study aimed to investigate role of the Claudin-5 (CLDN5) (a regulator of the permeability of BBB) and neuroinflammatory response in the comorbid behavioral disorders in experimental colitis in mice. Acetic acid was used to induce colitis in mice. 7 days after induction of colitis, behaviors including social interaction and locomotor activity as well as anxiety-like behaviors were evaluated. Then, the colon was extracted for gross and microscopic evaluations. The expression of CLDN5, TNF-α, IL1β and IL23 was measured by RT-PCR in the colon and hippocampus. Histopathologic evaluations demonstrated mucosal, submucosal, and crypt-related damages in the colon. The negative and positive number of social interactions significantly increased in the colitis group. A considerable increase in locomotor activities (horizontal and vertical components) shown in the colitis group. Mice in colitis group spent less time in the central zone in the open field apparatus. Gene expressions of TNF-α, IL1β, and IL23 increased and CLDN5 decreased in the colitis group. The barrier function of the intestine and brain would be impaired, partially at least, following colitis (as we observed decrease in CLDN5 gene expression). Furthermore, we found that beside inflammatory response in the colon, a neuro-immune response triggered in the hippocampus following colitis. These alterations probably, mediated comorbid behavioral disorders in acetic acid-induced colitis in mice.

The immunomodulatory effects of probiotics and azithromycin in dextran sodium sulfate-induced ulcerative colitis in rats via TLR4-NF-κB and p38-MAPK pathway

Ulcerative colitis (UC), a chronic autoimmune disease of the gut with a relapsing and remitting nature, considers a major health-care problem. DSS is a well-studied pharmacologically-induced model for UC. Toll-Like Receptor 4 (TLR4) and its close association with p-38-Mitogen-Activated Protein Kinase (p-38 MAPK) and nuclear factor kappa B (NF-κB) has important regulatory roles in inflammation and developing UC. Probiotics are gaining popularity for their potential in UC therapy. The immunomodulatory and anti-inflammatory role of azithromycin in UC remains a knowledge need. In the present rats-established UC, the therapeutic roles of oral probiotics (60 billion probiotic bacteria per kg per day) and azithromycin (40 mg per kg per day) regimens were evaluated by measuring changes in disease activity index, macroscopic damage index, oxidative stress markers, TLR4, p-38 MAPK, NF-κB signaling pathway in addition to their molecular downstream; tumor necrosis factor alpha (TNFα), interleukin (IL)1β, IL6, IL10 and inducible nitric oxide synthase (iNOS). After individual and combination therapy with probiotics and azithromycin regimens, the histological architecture of the UC improved with restoration of intestinal tissue normal architecture. These findings were consistent with the histopathological score of colon tissues. Each separate regimen lowered the remarkable TLR4, p-38 MAPK, iNOS, NF-κB as well as TNFα, IL1β, IL6 and MDA expressions and elevated the low IL10, glutathione and superoxide dismutase expressions in UC tissues. The combination regimen possesses the most synergistic beneficial effects in UC that, following thorough research, should be incorporated into the therapeutic approach in UC to boost the patients' quality of life.

Imatinib mitigates experimentally-induced ulcerative colitis: Possible contribution of NF-kB/JAK2/STAT3/COX2 signaling pathway

RATIONALE

Ulcerative colitis (UC) is a chronic immune-mediated disease characterized by recurrent inflammation, damage, and alteration of the large intestine's mucosal and submucosal surfaces. The purpose of this research was to evaluate the impact of tyrosine kinase inhibitor (imatinib) on experimentally induced UC in rats via acetic acid (AA).

METHODS

Male rats were randomly assigned to four groups: control, AA, AA + imatinib (10 mg/kg), and AA + imatinib (20 mg/kg). Imatinib (10 and 20 mg/kg/day) was orally supplied by oral syringe for one week before induction of UC. On the eighth day, Rats received enemas containing a 4 % solution of acetic acid to induce colitis. One day after inducing colitis, rats were euthanized and their colons were subjected to morphological, biochemical, histological, and immunohistochemical analysis.

RESULTS

Imatinib pretreatment significantly decreased macroscopic and histological damage scores, decreased disease activity index as well as colon mass index. In addition, imatinib successfully lowered the levels of malondialdehyde (MDA) in colonic tissues and enhanced superoxide dismutase activity (SOD) and glutathione content (GSH). Imatinib also reduced colonic levels of inflammatory interleukins (IL-23, IL-17, IL-6), JAK2 and STAT3. Furthermore, imatinib suppressed nuclear transcription factor kappa B (NF-kB/p65) level, and COX2 expression in colonic tissues.

SIGNIFICANCE

Imatinib may be a viable therapy option for UC as it halts the interaction network of NF-kB/JAK2/STAT3/COX2 signaling pathway.

Donepezil halts acetic acid-induced experimental colitis in rats and its associated cognitive impairment through regulating inflammatory/oxidative/apoptotic cascades: An add-on to its anti-dementia activity

Ulcerative colitis (UC) is a persistent inflammatory bowel disease (IBD) that is regarded as a risk factor for cognitive impairment. Donepezil (DON), a centrally acting acetylcholinesterase inhibitor (AChEI), is approved for the management of Alzheimer's disease (AD). We aimed to scrutinize the impact of DON on acetic acid (AA)-induced UC in rats and to evaluate its ability to attenuate inflammatory response, oxidative strain, and apoptosis in this model and its associated cognitive deficits. Rats were categorized into: normal, DON, AA, and AA + DON groups. DON (5 mg/kg/day) was administered orally for 14 days either alone or beginning with the day of UC induction. Colitis was evoked by a single transrectal injection of 1 ml of 4 % acetic acid. Results revealed that DON significantly improved the behavioral abnormalities with the mitigation of inflammation, apoptosis, and histopathological changes in the hippocampi of the colitis group. Moreover, DON significantly alleviated the macroscopic and microscopic changes associated with colitis. Interestingly, DON inhibited pro-inflammatory cytokines via suppression of AA-induced activation of nuclear factor kappa-B (NF-κB), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) in the colon, along with serum IL-1β. DON inhibited colon lipid peroxidation, restored the antioxidants with a significant amelioration of the degree of neutrophil infiltration, and repressed colitis-induced matrix metalloproteinases-9 (MMP-9) production. Furthermore, DON decreased the Bax/Bcl-2 ratio and caspase-3 protein expressions. Eventually, in lipopolysaccharide (LPS)-treated RAW 264.7 macrophage cells, DON suppressed nitric oxide (NO) release, demonstrating the ability of DON to significantly curtail inflammation in immune cells. Taken together, DON ameliorated experimental colitis and its linked cognitive dysfunction, possibly via its antioxidant effect and modulation of pro-inflammatory cytokines and apoptosis. Thereby, DON could be a therapeutic nominee for UC and associated neurological disorders.

Anticolitic activity of prodigiosin loaded with selenium nanoparticles on acetic acid-induced colitis in rats

Ulcerative colitis (UC) is a chronic autoimmune inflammatory disease associated with extensive mucosal damage. Prodigiosins (PGs) are natural bacterial pigments with well-known antioxidant and immunosuppressive properties. In the current study, we examined the possible protective effect of PGs loaded with selenium nanoparticles (PGs-SeNPs) against acetic acid (AcOH)-induced UC in rats. Thirty-five rats were separated into five equal groups with seven animals/group: control, UC, PGs (300 mg/kg), sodium selenite (Na2SeO3, 2 mg/kg), PGs-SeNPs (0.5 mg/kg), and 5-aminosalicylates (5-ASA, 200 mg/kg). Interestingly, PGs-SeNPs administration lessened colon inflammation and mucosal damage as indicated by inhibiting inflammatory markers upon AcOH injection. Furthermore, PGs-SeNPs improved the colonic antioxidant capacity and prevented oxidative insults as evidenced by the upregulation of Nrf2- and its downstream antioxidants along with the decreased pro-oxidants [reactive oxygen species (ROS), carbonyl protein, malondialdehyde (MDA), inducible nitric oxide synthase (iNOS), and nitric oxide (NO] in the colon tissue. Furthermore, PGs-SeNPs protected intestinal cell loss through blockade apoptotic cascade by decreasing pro-apoptotic proteins [Bcl-2-associated X protein (Bax) and caspase-3] and increasing anti-apoptotic protein, B cell lymphoma 2 (Bcl2). Collectively, PGs-SeNPs could be used as an alternative anti-colitic option due to their strong anti-inflammatory, antioxidant, and anti-apoptotic activities.

Flavocoxid halts both intestinal and extraintestinal alterations in acetic acid-induced colitis in rats

Ulcerative colitis (UC) is an idiopathic chronic inflammatory disorder mainly affecting the colon and rectum. The present investigation was undertaken to evaluate the potential protective effect of flavocoxid, a dual COX and LOX inhibitor, in colitis model in rats. UC was induced by instillation of 2 ml of 4% acetic acid (AA) into the colon using a pediatric catheter in rats, and flavocoxid (10 and 20 mg·kg^-1) was given once daily for 7 days before induction of colitis. Rats were sacrificed; sera were collected; colons and livers were isolated and then analyzed by biochemical, macroscopic, and histopathological examination. Pretreatment with flavocoxid (10 and 20 mg·kg^-1) significantly reduced serum levels of alanine transaminase (ALT) (43.7 ± 7 and 76.2 ± 7.3 vs. 288.7 ± 31.4 in AA group) and aspartate transaminase (AST) (179.5 ± 22.2 and 200.5 ± 14 vs. 392.7 ± 35.6 in AA group) (p>0.05). Also, it decreased malondialdehyde (MDA) and nitric oxide (NOx) levels in both colonic and hepatic tissues. Moreover, flavocoxid effectively elevated colonic and hepatic reduced glutathione (GSH) level and superoxide dismutase (SOD) activity when compared to AA group (p>0.05). Additionally, flavocoxid significantly decreased levels of tumor necrosis factor-α (TNF-α) (878.2 ± 13.4 and 560.1 ± 2.9 vs. 1378.1 ± 31 in AA group) in colonic tissues and (701 ± 6.9 and 442.5 ± 8.2 vs. 1501 ± 9.4 in AA group) in hepatic tissues, nuclear factor kappa B (NF-κBp65) (493.8 ± 6.8 and 368.7 ± 3.1 vs. 659.2 ± 9.4 in AA group) in colonic tissues and (358 ± 5.1 and 163.5 ± 7.8 vs. 732.5 ± 4.5 in AA group) in hepatic tissues, myeloperoxidase (MPO) (15.7 ± 0.3 and 13 ± 0.2 vs. 20.9 ± 0.5 in AA group) in colonic tissues and (20.4 ± 0.3 and 16.3 ± 0.3 vs. 23.9 ± 1.2 in AA group) in hepatic tissues, and inducible nitric oxide synthase (iNOS) (12.5 ± 0.3 and 10 ± 0.2 vs. 16 ± 0.1 in AA group) in colonic tissues and (14.1 ± 0.04 and 11.5 ± 0.08 vs. 17.8 ± 0.1 in AA group) in hepatic tissues (p>0.05). Furthermore, it down-regulated Bax and caspase-3 expression in colonic and hepatic tissues upon comparison with AA group. Collectively, flavocoxid conferred a protective impact against acetic acid-induced colitis in rats via attenuating oxidative stress, inflammation, and apoptosis.

Molsidomine alleviates acetic acid-induced colitis in rats by reducing oxidative stress, inflammation and apoptosis

Ulcerative colitis (UC) is a subcategory of intestinal inflammatory bowel disease characterized by up-regulation of proinflammatory cytokines and oxidative stress. The current study was designed to assess the probable protective effect of the nitric oxide (NO) donor, molsidomine, in experimental colitis model in rats. Rats were haphazardly classified into four groups: control, acetic acid, acetic acid + molsidomine (1 mg/kg) and acetic acid + molsidomine (2 mg/kg). Molsidomine (1 and 2 mg/kg/day) was administered by intra-peritoneal injection for 7 days prior to induction of UC. On the 8th day, colitis was induced by intra-rectal instillation of 2 ml of (4% v/v) acetic acid in normal saline using a pediatric plastic catheter. The rats were sacrificed 1 day following colitis induction, blood samples were obtained; colons and livers were isolated then underwent macroscopic, biochemical, histopathological and immunohistochemical examination. Pretreatment with molsidomine significantly reduced disease activity index, colon mass index, colonic macroscopic and histological damage. Besides, molsidomine significantly reduced the serum levels of alanine transaminase (ALT) (58.7 ± 8.9 & 59.7 ± 8 vs 288.75 ± 31.4 in AA group) and aspartate transaminase (AST) (196.2 ± 37.4 & 204 ± 30 vs 392.7 ± 35.6 in AA group). Moreover, molsidomine effectively decreased malondialdehyde (MDA) and total nitrate/nitrite (NOx) contents, and up regulated the enzymatic activity of superoxide dismutase (SOD) and glutathione level (GSH) in colonic and hepatic tissues. With regard to anti-inflammatory mechanisms, molsidomine suppressed tumor necrosis factor-alpha (TNF-α) (792.5 ± 16.7 & 448 ± 12.1 vs 1352.5 ± 45.8 in AA group) in colonic tissues and (701 ± 19 & 442.5 ± 22.5 vs 1501 ± 26 in AA group) in hepatic tissues as well as nuclear transcription factor kappa B (NF-kB/p65) levels (416.2 ± 4.1 & 185.5 ± 14.2 vs 659.2 ± 11.5 in AA group) in colonic tissues and (358 ± 6.2 & 163.5 ± 9.6 vs 732.5 ± 5.5 in AA group) in hepatic tissues. In addition, molsidomine significantly decreased inducible nitric oxide synthase (iNOS) levels (8.1 ± 0.1 & 4.9 ± 0.1 vs 16 ± 0.1 in AA group) in colonic tissues and (8.6 ± 0.3 & 6.1 ± 0.1 vs 17.8 ± 0.1 in AA group) in hepatic tissues, and myeloperoxidase (MPO) contents (10.5 ± 0.4 & 6.6 ± 0.3 vs 20.9 ± 0.6 in AA group) in colonic tissues and (13.1 ± 0.2 & 6.3 ± 0.06 vs 23.9 ± 1.4 in AA group) in hepatic tissues at p > 0.05. Furthermore, it suppressed apoptosis by reducing expression of Caspase 3 and Bax in colonic and hepatic tissues. Therefore, molsidomine might be a promising candidate for the treatment of UC.

Sodium Selenite Attenuates Balloon Injury-Induced and Monocrotaline-Induced Vascular Remodeling in Rats

Vascular remodeling (VR), induced by the massive proliferation and reduced apoptosis of vascular smooth muscle cells (VSMCs), is primarily responsible for many cardiovascular conditions, such as restenosis and pulmonary arterial hypertension. Sodium selenite (SSE) is an inorganic selenium, which can block proliferation and stimulate apoptosis of tumor cells; still, its protective effects on VR remains unknown. In this study, we established rat models with carotid artery balloon injury and monocrotaline induced pulmonary arterial hypertension and administered them SSE (0.25, 0.5, or 1 mg/kg/day) orally by feeding tube for 14 consecutive days. We found that SSE treatment greatly ameliorated the development of VR as evidenced by an improvement of its characteristic features, including elevation of the ratio of carotid artery intimal area to medial area, right ventricular hypertrophy, pulmonary arterial wall hypertrophy and right ventricular systolic pressure. Furthermore, PCNA and TUNEL staining of the arteries showed that SSE suppressed proliferation and enhanced apoptosis of VSMCs in both models. Compared with the untreated VR rats, lower expression of PCNA and CyclinD1, but higher levels of Cleaved Caspase-3 and Bax/Bcl-2 were observed in the SSE-treated rats. Moreover, the increased protein expression of MMP2, MMP9, p-AKT, p-ERK, p-GSK3β and β-catenin that occurred in the VR rats were significantly inhibited by SSE. Collectively, treatment with SSE remarkably attenuates the pathogenesis of VR, and this protection may be associated with the inhibition of AKT and ERK signaling and prevention of VSMC’s dysfunction. Our study suggest that SSE is a potential agent for treatment of VR-related diseases.

Antiulcerogenic effect of melittin via mitigating TLR4/TRAF6 mediated NF-κB and p38MAPK pathways in acetic acid-induced ulcerative colitis in mice

Ulcerative colitis (UC) is a chronic disease driven primarily by uncontrolled pervasive inflammatory responses affecting the colon and rectum. Currently available medications carry multiple detrimental adverse effects, which have emphasized the mandatory need for safer and more efficient novel therapeutic alternatives. Melittin is the main constituent of bee venom and exhibits potent anti-inflammatory properties. The antiulcerogenic effect of oral melittin (40 μg/kg) was explored in the current study using the acetic acid-induced colitis model. Increase in body weight and decrease in colon mass index were observed in the melittin group. Microscopically, melittin ameliorated acetic acid-induced histological damage. Melittin administration has efficiently amended the elevated levels of the cytokines, tumor necrosis factor (TNF-α) and interleukin 6 (IL-6) seen in the colitis group. This was accompanied by inhibition of the upstream signaling molecules, Toll-like receptor 4 (TLR4), tumor necrosis factor receptor (TNF-R)-associated factor (TRAF6), mitogen-activated protein kinase 38 (p38 MAPK), and nuclear factor kappaB (NF-κB) in the melittin group. Moreover, treatment with melittin resulted in marked decrease in colonic level of prostaglandin E2 (PGE2) together with the enzymes involved in its synthesis, secretory phospholipase A2 (sPLA2) and cyclooxygenase 2 (COX-2). Additionally, melittin has attenuated acetic acid-induced oxidative stress as manifested by the significant diminishment in malondialdehyde (MDA) as well as the increase in superoxide dismutase (SOD) and reduced glutathione (GSH) levels. Therefore, melittin mitigated UC pathogenesis and could be considered as a potent and promising therapeutic alternative for UC treatment.

Spray dried formulation of mesalamine embedded with probiotic biomass for the treatment of ulcerative colitis: in-vitro and in-vivo studies

This study is using the targeted approach and anti-inflammatory action of the probiotic biomass to lessen the side effects of therapeutic agents of ulcerative colitis. The aim of the present study is to prepare mesalamine loaded eudragit S-100 with probiotic microparticles by spray drying method. The in-vitro release of the optimized formulation was 90.55 ± 2.42 in 24 hr, which display controlled drug release of mesalamine at a particular region. Mesalamine loaded eudragit S-100 with probiotic microparticles (F12) presented average particle size of 4.91 µm. The statistical analysis was done by one way ANOVA and then comparison test of Bonferroni was done and p values <.05 were considered as significant. The effects of spray dried microparticles over inflamed Caco-2 cell were also evaluated by determining the concentration of IL-8. From in-vivo study it was seen that pretreatment of mesalamine with probiotic prevents DNBS (Dinitrobenzenesulfonic acid) induced colitis in rats and represents protective action against ulcerative colitis because of its antioxidant and anti-inflammatory actions. The results give the foundation for a combination of targeted approach along with the anti-inflammatory potential of the probiotic which might help to decrease the problems which are seen with the traditional cure and management of ulcerative colitis.

Radioprotective Effect of Sodium Selenite on Mandible of Irradiated Rats

The purpose of this study was to test the radioprotective effect of selenium in the bone microarchitecture of irradiated rats mandibles. Forty rats were separated into 4 groups with 10 animals: control group (CG), irradiated group (IG), sodium selenite group (SSG) and sodium selenite irradiated group (SSIG). A single dose of 0.8 mg/kg sodium selenite was administered intraperitoneally in the SSG and SSIG groups. One hour later, animals of IG and SSIG groups were irradiated with 15 Gy of x-rays. Forty days after radiation a bilateral extraction of the mandibular first molars was performed. After the extraction procedure, five rats were killed after fifteen days and others five after thirty days. Micro- computed tomography was used to evaluate cortical and trabecular bone of each rat. The mean and standard deviation of each bone microarchitecture parameter were analyzed using the statistical test of two-way Analysis of Variance (ANOVA). At 15 days, the bone volume presented higher values in the CG and SSG groups (p=0.001). The same groups presented statistically significant higher values when bone volume fraction (p<0.001) and trabecular thickness (p<0.001) were analyzed. At 30 days, it was observed that in relation to the bone volume fraction, SSG group presented the highest value while SSIG group had the lowest value, with statistically significant difference (p=0.016). Sodium selenite demonstrated a median radioprotective effect in the bone microarchitecture of irradiated mandibles, which indicates the substance may be a potential radioprotective agent against chronic effects of high doses of ionizing radiation.