Emu Oil Combined with Lyprinol™ Reduces Small Intestinal Damage in a Rat Model of Chemotherapy-Induced Mucositis

Fig seed oil improves intestinal damage caused by 5-FU-induced mucositis in rats

Intestinal mucositis poses a significant concern associated with cancer therapy. This study aims to investigate the protective and/or healing effect of fig seed oil (FSO) on 5-fluorouracil (5-FU)-induced intestinal mucositis by targeting inflammatory markers and histologic changes in rats. Albino Wistar adult rats were randomly divided into four groups, including three male and three female animals. All the animals in the four groups had a normal standard diet and water throughout the experimental period, which lasted up to 11 days. Rats were administered FSO 0.6 mL (mucositis FSO group) and FSO 0.2 mL (mucositis FSO-R group) daily throughout the experiment. These two groups and one additional group (mucositis group) were given an intraperitoneal injection of 5-FU (300 mg/kg) on Day 5 of the experiment. In contrast, the fourth group (Control group) was given an intraperitoneal saline injection on Day 5 of the experiment. FSO treatment ameliorated 5-FU-induced intestinal mucositis. On immunohistologic examination, FSO suppressed significantly the activation of NF-κB and expression of IL-β and TNF-α of the harvested intestinal tissue. The reduced dose FSO (mucositis FSO-R) was as effective as the full dose (mucositis FSO) in suppressing IL-β and TNF-α production, but was not as effective as the full dose in suppressing NF-κB. On light microscopy, FSO attenuated significantly 5-FU-induced anomalies, such as the reduction of intestinal villus length and Goblet cell count. The reduced dose FSO (mucositis FSO-R) was as effective as the full dose (mucositis FSO) in restoring villus length, but was not as effective as the full dose in restoring Goblet cell count. The findings of the study suggest that FSO inhibits 5-FU-induced intestinal mucositis via modulation of mucosal inflammation.

Vitamins and fatty acids against chemotherapy-induced intestinal mucositis

Chemotherapy has allowed an increase in cancer survivorship, but it causes important adverse effects. Mucositis affecting the gastrointestinal tract is one of the main problems acutely caused by many antineoplastic drugs, such as 5-fluorouracil or methotrexate. Mucositis may cause pain, diarrhea, anorexia, weight loss, systemic infections and even death. This narrative review focuses on intestinal mucositis and the role that some nutraceuticals, namely vitamins (both lipid- and water-soluble) as well as fatty acids (FAs) and lipid-based products, can have in it. In preclinical (cell cultures, animal models) and/or human studies, vitamins A, D, E, B2, B9 and C, omega-3 long-chain FAs (eicosapentaenoic, docosahexaenoic, conjugated linoleic acid), short-chain FAs (mainly butyrate), medium-chain FAs (capric acid), and different lipid-based products (emu oil, extra-virgin olive oil, lipid replacement therapy), enriched in beneficial FAs and natural antioxidants, were shown to exert beneficial effects (both preventative and palliative) against chemotherapy-induced intestinal mucositis. Although the exact mechanisms of action involved in these effects are not yet well known, our review highlights the interest of investigating on diet and nutrition to implement scientifically robust strategies to improve protection of cancer patients against chemotherapy-induced adverse effects.

Emu Oil and zinc monoglycerolate independently reduce disease severity in a rat model of ulcerative colitis

Ulcerative colitis is characterized by colonic inflammation. Previously, Emu Oil protected the intestine against experimentally-induced inflammatory intestinal disorders. Zinc monoglycerolate (ZMG) polymer, formed by heating zinc oxide with glycerol, demonstrated anti-inflammatory and wound healing properties. We aimed to determine whether ZMG, alone or in combination with Emu Oil, could reduce acute colitis severity in rats. Male Sprague Dawley rats (n = 8/group) were orally-administered either vehicle, ZMG, Emu Oil (EO) or ZMG combined with EO (ZMG/EO) daily. Rats were provided ad libitum access to drinking water (Groups 1-4) or dextran sulphate sodium (DSS; 2%w/v; Groups 5-8) throughout the trial (days 0-5) before euthanasia on day 6. Disease activity index, crypt depth, degranulated mast cells (DMCs) and myeloperoxidase (MPO) activity were assessed. p < 0.05 was considered significant. DSS increased disease severity (days 3-6) compared to normal controls (p < 0.05). Importantly, in DSS-administered rats, ZMG/EO (day 3) and ZMG (day 6) reduced disease activity index compared to controls (p < 0.05). Following DSS consumption, distal colonic crypts lengthened (p < 0.01), occurring to a greater extent with EO compared to ZMG and ZMG/EO (p < 0.001). DSS increased colonic DMC numbers compared to normal controls (p < 0.001); an effect decreased only by EO (p < 0.05). Colonic MPO activity increased following DSS consumption (p < 0.05); notably, ZMG, EO and ZMG/EO treatments decreased MPO activity compared to DSS controls (p < 0.001). EO, ZMG and ZMG/EO did not impact any parameter in normal animals. Emu Oil and ZMG independently decreased selected indicators of colitic disease severity in rats; however, the combination did not reveal any additional benefit.

Experimental Chemotherapy-Induced Mucositis: A Scoping Review Guiding the Design of Suitable Preclinical Models

Mucositis is a common and most debilitating complication associated with the cytotoxicity of chemotherapy. The condition affects the entire alimentary canal from the mouth to the anus and has a significant clinical and economic impact. Although oral and intestinal mucositis can occur concurrently in the same individual, these conditions are often studied independently using organ-specific models that do not mimic human disease. Hence, the purpose of this scoping review was to provide a comprehensive yet systematic overview of the animal models that are utilised in the study of chemotherapy-induced mucositis. A search of PubMed/MEDLINE and Scopus databases was conducted to identify all relevant studies. Multiple phases of filtering were conducted, including deduplication, title/abstract screening, full-text screening, and data extraction. Studies were reported according to the updated Preferred Reporting Items for Systematic reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines. An inter-rater reliability test was conducted using Cohen's Kappa score. After title, abstract, and full-text screening, 251 articles met the inclusion criteria. Seven articles investigated both chemotherapy-induced intestinal and oral mucositis, 198 articles investigated chemotherapy-induced intestinal mucositis, and 46 studies investigated chemotherapy-induced oral mucositis. Among a total of 205 articles on chemotherapy-induced intestinal mucositis, 103 utilised 5-fluorouracil, 34 irinotecan, 16 platinum-based drugs, 33 methotrexate, and 32 other chemotherapeutic agents. Thirteen articles reported the use of a combination of 5-fluorouracil, irinotecan, platinum-based drugs, or methotrexate to induce intestinal mucositis. Among a total of 53 articles on chemotherapy-induced oral mucositis, 50 utilised 5-fluorouracil, 2 irinotecan, 2 methotrexate, 1 topotecan and 1 with other chemotherapeutic drugs. Three articles used a combination of these drugs to induce oral mucositis. Various animal models such as mice, rats, hamsters, piglets, rabbits, and zebrafish were used. The chemotherapeutic agents were introduced at various dosages via three routes of administration. Animals were mainly mice and rats. Unlike intestinal mucositis, most oral mucositis models combined mechanical or chemical irritation with chemotherapy. In conclusion, this extensive assessment of the literature revealed that there was a large variation among studies that reproduce oral and intestinal mucositis in animals. To assist with the design of a suitable preclinical model of chemotherapy-induced alimentary tract mucositis, animal types, routes of administration, dosages, and types of drugs were reported in this study. Further research is required to define an optimal protocol that improves the translatability of findings to humans.

Neuroimmunological complications arising from chemotherapy-induced gut toxicity and opioid exposure in female dark agouti rats

Cancer patients may experience symptom clusters, including chemotherapy-induced (CI) gut toxicity (CIGT) and cognitive impairment. Analgesic selection for pain associated with CIGT is difficult as opioids induce glial reactivity and unwanted side effects. This study quantified central glial reactivity and proinflammatory effects in rats with CIGT using three mechanistically different analgesics. Regional adaptations were indicative of immune-to-brain signaling routes. Utilizing a 5-fluorouracil-induced GT (5IGT) rat model and analgesic intervention (carprofen (CAR), buprenorphine (BUP), and tramadol (TRAM)), spinal and brain neuroimmune modulation was examined via microglial, astrocyte, and proinflammatory (cluster of differentiation molecule 11b; CD11b, glial fibrillary associated protein; GFAP, and interleukin-1 beta; IL1β) reactivity marker expression changes by western blot analysis. 5IGT significantly increased thoracic GFAP (p < 0.05) and IL-1β (p < 0.0001) expression, CAR and BUP ameliorated these effects. BUP and TRAM with 5-FU synergistically increased hippocampal GFAP expression. CAR administered with 5IGT significantly elevated hippocampal and thoracic CD11b expression levels (p < 0.05). The neuroimmune responses observed in this study suggest activation of peripheral-to-central immune signaling pathways. We speculate that the opioid-induced hippocampal changes inferred a humorally mediated mechanism, whereas thoracic neuroimmune modifications indicated activation of an indirect neural route. Although TRAM ameliorated 5IGT-intestinal inflammation, this opioid presents complications relating to bodyweight and regional glial dysregulation (neuroinflammation) and may not be optimal in the management of pain associated with 5IGT. The chemotherapy-induced gut-derived neuroimmune consequences observed suggest a potential mechanistic contribution to central components of the cancer symptom cluster experience, while the opioid-related glial changes have implications for optimal pain management in this setting warranting further investigation.

Emu Oil and Saireito in combination reduce tumour development and clinical indicators of disease in a mouse model of colitis-associated colorectal cancer

BACKGROUND

Emu Oil (EO) previously demonstrated therapeutic potential in a mouse model of colitis-associated CRC (CA-CRC). Saireito, a traditional Japanese medicine, has not been investigated in CA-CRC.

AIM

To determine whether EO and Saireito could be therapeutic in an azoxymethane (AOM)/dextran sulphate sodium (DSS) model of CA-CRC.

METHODS

Female C57BL/6 mice were assigned to groups (n = 10/group); 1) saline control, 2) saline+Saireito, 3) saline+EO, 4) saline+EO/Saireito, 5) AOM/DSS control, 6) AOM/DSS+Saireito, 7) AOM/DSS+EO and 8) AOM/DSS+EO/Saireito. Mice were intraperitoneally injected with saline or AOM (7.4 mg/kg) on day 0 and underwent three DSS/water cycles (2%w/v DSS for 7 days, 14 days water). Mice were orally-gavaged with either water (80 µL), Saireito (80 µL), EO (80 µL) or EO/Saireito (160 µL; 80 µL EO + 80 µL Saireito) thrice weekly. Daily bodyweight and disease activity index (DAI) were recorded and colonoscopies performed on days 20, 41 and 62. Mice were euthanized on day 63. p < 0.05 was considered statistically significant.

RESULTS

AOM/DSS induced significant bodyweight loss throughout the trial (max -36%), which was attenuated by Saireito (max +7%), EO (max +5%) and EO/Saireito (max +14%; p < 0.05). AOM/DSS increased DAI compared to saline controls (p < 0.05), which was reduced by Saireito, EO and EO/Saireito (p < 0.05). All treatments reduced colonoscopically-assessed colitis severity (days 20 and 41; p < 0.05). EO/Saireito further decreased colitis severity compared to Saireito and EO alone (day 20; p < 0.05). Finally, EO and EO/Saireito resulted in fewer colonic tumours compared to AOM/DSS controls (p < 0.05).

CONCLUSION

Combined EO and Saireito reduced disease and tumour development in AOM/DSS mice, suggesting therapeutic potential in CA-CRC.

Emu Oil Attenuates Disease Severity and Results in Fewer Large Colonic Tumors in a Mouse Model of Colitis-Associated Colorectal Cancer

Ulcerative colitis patients have an increased risk of developing colorectal cancer (CRC). The aim of the current study was to determine whether Emu Oil (EO) could reduce the severity of colitis, thereby inhibiting colitis-associated CRC (CA-CRC) development. Female C57BL/6 mice (n = 8/group) were injected (i.p.) with saline or azoxymethane (AOM) (7.4 mg/kg). Mice underwent three dextran sulfate sodium (DSS)/water cycles. Mice were orally-administered either water (160 µL) or EO (80 µL or 160 µL) thrice weekly and euthanized after 12 weeks. AOM/DSS decreased bodyweight compared with normal controls (max. 20%; p < 0.05). In AOM/DSS mice, EO (160 µL) increased bodyweight compared with untreated and 80 µL EO-treated mice (max. 10%; p < 0.05). Both volumes of EO reduced disease activity index (DAI) scores on day 49, 56-63 (max. 40%; p < 0.05), compared with AOM/DSS controls. Histological damage was increased in the distal colon of AOM/DSS mice, and reduced by EO (160 µL; p < 0.05). Mucin-secreting goblet cells were increased by AOM/DSS compared to normal, with no effect observed following EO treatment (p > 0.05). Large tumor numbers were decreased in EO-treated mice (160 µL; 2 ± 0.6) compared with AOM/DSS controls (5 ± 0.7; p < 0.05). EO did not impact overall tumor number (p > 0.05). Other analyses remained unchanged across groups (p > 0.05). EO demonstrates promise as an adjunct to conventional treatment options for colitis management.

Emu oil and grape seed extract reduce tumour burden and disease parameters in murine colitis-associated colorectal cancer

Ulcerative colitis is an incurable condition whereby patients are at an increased risk of developing colorectal cancer (CRC). We aimed to investigate the combination of Emu oil (EO) and grape seed extract (GSE) in an azoxymethane (AOM)/dextran sulphate sodium (DSS) model of colitis-associated CRC (CA-CRC). C57BL/6 mice (n = 10/group) were injected i.p. with saline or AOM (7.4 mg/kg) and underwent three DSS/water cycles. Mice were orally-gavaged thrice weekly with water (80 μl), EO (80 μl), GSE (80 μl; 400 mg/kg) or combined EO/GSE (160 μl). Mice were euthanized on day 63. AOM/DSS induced significant bodyweight loss (max -21%) and increased disease activity index (DAI) (max +83%) throughout the trial (P < 0.05). EO (max -53%), GSE (max -51%) and EO/GSE (max -71%) reduced DAI scores in AOM/DSS mice in all DSS cycles (P < 0.05). EO/GSE-treatment in AOM/DSS mice resulted in further DAI reduction compared with EO (max -62%) and GSE (max -71%) alone (P < 0.05). AOM/DSS mice presented with severe colonoscopically-assessed colitis at all time-points, which was reduced by EO, GSE and EO/GSE (P < 0.05). EO, GSE and EO/GSE reduced the number of colonic tumours compared with AOM/DSS controls (P < 0.05). Myeloperoxidase (acute inflammation) and fluorescein isothiocyanate-dextran levels (intestinal permeability) were increased in AOM/DSS controls (P < 0.05). EO (-58%) and EO/GSE (-77%) reduced fluorescein isothiocyanate-dextran compared with AOM/DSS controls (P < 0.05), with no effect on myeloperoxidase. Histologically-assessed severity scores were increased in the distal colon of AOM/DSS mice compared with saline (P < 0.05), with no effect observed following treatment. The combination of EO and GSE improved clinical indicators and reduced colonic tumours in AOM/DSS treated mice, suggesting potential in CA-CRC management.

Orally administered emu oil attenuates disease in a mouse model of Crohn's-like colitis

Crohn's disease is a severe, incurable inflammatory bowel disease. Orally administered emu oil has demonstrated anti-inflammatory properties in previous models of gastrointestinal disease. We aimed to determine whether orally administered emu oil could attenuate disease in a mouse model of Crohn's-like colitis. Female ARC(s) mice (CD-1 equivalent, n = 10/group) were intra-rectally administered water (120 μL) or trinitrobenzene sulfonic acid (TNBS; 3 mg in 50% ethanol; 120 μL bolus) on day 0. Mice were orally administered water (80 μL) or emu oil (80 μL or 160 μL) daily for five days and euthanized on day six. Bodyweight and disease activity were recorded daily. Colonoscopy, burrowing activity, facial grimace, histological parameters (damage severity, small intestinal villus height/crypt depth and colonic crypt depth), myeloperoxidase activity and intestinal permeability were assessed. P < 0.05 was considered statistically significant. TNBS decreased bodyweight (days 1, 2, 4; P < 0.05) and increased disease activity (days 1-6; P < 0.01), compared to normal controls. Emu oil (80 μL) attenuated disease activity on days 5-6 (P < 0.05), although bodyweight loss was not significantly impacted (P > 0.05). Facial grimace and colonoscopy scores were significantly increased in TNBS-control mice; effects attenuated by both volumes of emu oil (P < 0.001). TNBS increased histological damage severity compared to normal controls (P < 0.05); an effect attenuated by 80 μL emu oil (proximal and distal colon; P < 0.05) and 160 μL emu oil (distal colon; P < 0.01). In the ileum, villus height and crypt depth were unaffected by TNBS or emu oil treatment compared to normal (P > 0.05). TNBS-induced distal colonic crypt lengthening was unaffected following emu oil administration (P > 0.05). Remaining parameters, including burrowing, myeloperoxidase activity and intestinal permeability, were unchanged across all treatment groups (P > 0.05). In normal mice, emu oil treatment did not significantly impact any parameter compared to normal controls. In conclusion, emu oil reduced overall disease severity and facial grimace scores in TNBS mice. These results suggest therapeutic potential for orally administered emu oil in the management of Crohn's disease.

Supplementation with L-Arginine Decreases Jejunal Lesions and Micronucleus Formation Induced by 5-Fluorouracil in Rats

The objective of this study was to evaluate the effect of L-arginine supplementation on the formation of jejunal lesions and micronuclei in Wistar rats following 5-fluorouracil (5-FU) treatment. Fifty rats were separated into five groups: CG served as the control group, G_Arg was supplemented L-arginine, G_5-FU was administered 5-FU, G_Arg+5-FU was supplemented L-arginine/day and administered 5-FU, and G_ciclo served as a positive control group for micronuclei formation. Jejunal lesions were assessed by histopathological analysis using a scoring system with a maximum of 39 points, based on the following lesions: lymph vessel dilatation, cubic enterocytes, villous flattening, villus fusion, interstitial edema, and apical necrosis of the villi. Micronuclei were counted in polychromatic erythrocytes from the femur bone marrow. The control and G_Arg rats had the lowest number of jejunal lesions (6.4 ± 2.8 and 5.3 ± 2.4, respectively) and micronuclei (1.9 ± 0.6 and 1.1 ± 0.3, respectively) while the G_5-FU rats had the highest number of jejunal lesions (24.2 ± 4.9) and micronuclei (36.0 ± 8.5). The G_Arg+5-FU rats showed significantly reduced (P < 0.05) jejunal lesions (10.2 ± 4.9) and micronuclei (15.4 ± 5.9). In conclusion L-arginine supplementation potentially reduces the jejunal lesions and DNA damage caused by 5-FU.

Animal models of mucositis: critical tools for advancing pathobiological understanding and identifying therapeutic targets

PURPOSE OF REVIEW

Mucositis remains a prevalent, yet poorly managed side effect of anticancer therapies. Mucositis affecting both the oral cavity and gastrointestinal tract predispose to infection and require extensive supportive management, contributing to the growing economic burden associated with cancer care. Animal models remain a critical aspect of mucositis research, providing novel insights into its pathogenesis and revealing therapeutic targets. The current review aims to provide a comprehensive overview of the current animal models used in mucositis research.

RECENT FINDINGS

A wide variety of animal models of mucositis exist highlighting the highly heterogenous landscape of supportive oncology and the unique cytotoxic mechanisms of different anticancer agents. Golden Syrian hamsters remain the gold-standard species for investigation of oral mucositis induced by single dose and fractionated radiation as well as chemoradiation. There is no universally accepted gold-standard model for the study of gastrointestinal mucositis, with rats, mice, pigs and dogs all offering unique perspectives on its pathobiology.

SUMMARY

Animal models are a critical aspect of mucositis research, providing unprecedent insight into the pathobiology of mucositis. Introduction of tumour-bearing models, cyclic dosing scheduled, concomitant agents and genetically modified animals have been integral in refining our understanding of mucositis.

Chemotherapy-induced mucositis development in a murine model of colitis-associated colorectal cancer

Objectives: Ulcerative colitis is an incurable inflammatory bowel disease that increases the risk of colorectal cancer (CRC). 5-Fluorouracil (5-FU) is the predominant chemotherapy for CRC patients; however, undesirable side-effects, including mucositis, are common. This study utilised 5-FU-treatment in a model of colitis-associated CRC to develop a pre-clinical setting of intestinal mucositis coincident with manifestation of CRC.Materials/methods: On day 0, female C57BL/6 mice (n = 10/group); (1) saline control, (2) AOM/DSS control, or (3) AOM/DSS + 5-FU were injected with saline or AOM (i.p; 7.4 mg/kg). Groups 2 and 3 underwent cycles of seven days 2%w/v DSS followed by 14 days plain water. After three cycles, 5-FU was administered weekly (i.p; 75 mg/kg) to group 3 for five weeks. Clinical indicators were measured daily and colonoscopy performed at four time-points. Mice were euthanized at 13 weeks (day 91). Intestinal sections were collected for histological and biochemical analyses. p < .05 was considered significant.Results: AOM/DSS resulted in bodyweight loss, increased disease activity index, colitis-severity and tumour number compared to saline controls (p < .05). 5-FU-treatment in AOM/DSS mice decreased bodyweight and disease activity index at selected time-points compared to AOM/DSS controls (p < .05). 5-FU did not impact colitis-severity or overall tumour burden; although, resulted in fewer small tumours compared to AOM/DSS controls (<2mm; p < .05). AOM/DSS increased histological severity scores in intestinal sections (p < .05), however, 5-FU-treatment did not further increase histologically-assessed disease severity (p > .05).Conclusion: Weekly 5-FU administration at a dose of 75 mg/kg was insufficient to reduce overall tumour burden or induce intestinal mucositis in the AOM/DSS mouse model.

Armillariella Oral Solution Ameliorates Small Intestinal Damage in a Mouse Model of Chemotherapy-Induced Mucositis

Background: Armillariella oral solution (AOS) shows therapeutic effect on gastrointestinal disorders. We aimed to investigate the potential efficacy of AOS on chemotherapy-induced intestinal mucositis in mice. Methods: Intestinal mucositis was induced in C57BL/6 mice by daily intraperitoneal injection of 5-FU (50 mg/kg) for 7 days. Effects of AOS (at 1, 5, and 10 mL/kg), or combined Bifidobacterium and Lactobacillus (CBL, 450 mg/kg) on the accompanying morphometry and histology, expression of Ki-67, caspase-3, Lgr5 and apoptosis of intestinal crypt cells were assessed. Results: Continuous administration of 5-FU to mice caused severe intestinal mucositis, which was histologically characterized by the destruction of intestinal crypts and shortening of villi, accompanied by diarrhea and body weight loss. Daily AOS administration dose-dependently reduced the severity of intestinal mucositis, diarrhea and body weight loss. Similar beneficial effects were observed with CBL. The expression of Ki-67 and Lgr5 decreased and the expression of caspase-3, and the number of apoptotic cells increased 24 h after the first 5-FU administration (P < 0.05), and these responses were significantly reduced by AOS treatment (P < 0.05, at 5 or 10 mL/kg). Conclusions: AOS can alleviate 5-FU-induced mucositis in mice via increasing Lgr5 expression and suppressing apoptotic responses in the intestinal crypt cells.

Combined Nutraceuticals: A Novel Approach to Colitis-Associated Colorectal Cancer?

Ulcerative colitis is an unremitting and lifelong inflammatory bowel disease that is increasing in prevalence worldwide. Patients display various clinical symptoms such as abdominal pain, diarrhea and fatigue. The etiology of ulcerative colitis remains unknown and the current pharmaceutical treatments are variably effective and not curative, highlighting the need for improved therapeutic approaches. Furthermore, patients with ulcerative colitis are at an increased risk of developing colorectal cancer. Some naturally sourced agents, named nutraceuticals, have been identified to possess anti-inflammatory and antioxidant properties. Of particular interest is Emu Oil, grape seed extract and Japanese Kampo medicine. Previously, Emu Oil has protected and repaired intestinal damage in models of gastrointestinal diseases including colitis and colitis-associated colorectal cancer. Additionally, grape seed extract possesses anticancer properties in vitro. Moreover, Kampo medicine, composed of herbal ingredients, is widely used in Japan for the treatment of various medical conditions and has demonstrated efficacy in targeting cancer cells in vitro. Nutraceuticals in combination have not yet been widely investigated in a setting of colitis-associated colorectal cancer. Investigation into the efficacy of Emu Oil combined with other nutraceuticals, including grape seed extract and Kampo medicine, is warranted as they may provide a novel approach to conventional colitis and colorectal cancer management.

Emu Oil reduces disease severity in a mouse model of chronic ulcerative colitis

Objective: Ulcerative colitis (UC) is characterized by mucosal inflammation and ulceration of the large intestine. Emu Oil (EO) has been reported to protect the intestine against mucositis, NSAID-enteropathy, UC-associated colorectal cancer and acute UC. We aimed to determine whether EO could reduce the severity chronic UC in mice. Methods: Female C57BL/6 mice (n = 10/group) were orally administered (gavage) water (Groups 1-2) or EO (Groups 3: low dose-80 µl and 4: high dose-160 µl), thrice weekly. Group 1 mice consumed plain drinking water throughout the trial. Groups 2-4 mice underwent two cycles [each consisting of seven days dextran sulfate sodium (DSS; 2% w/v) and 14 days water], followed by a third DSS week. All mice were euthanized two days later (day 51). Bodyweight, disease activity index (DAI), burrowing activity, myeloperoxidase activity, crypt depth and histologically assessed damage severity were assessed. p < .05 was considered significant. Results: DSS decreased bodyweight and increased DAI compared to normal controls (p < .05), which was partially attenuated by both EO doses (p < .05). Burrowing activity was impaired in DSS-controls compared to normal controls (days 27 and 40); an effect prevented by both EO doses (p < .05). DSS increased colonic myeloperoxidase activity and crypt depth compared to controls (p < .05), with no significant EO effect. Moreover, DSS increased colonic damage severity compared to normal controls (p < .001). Importantly, both EO doses decreased distal colonic damage severity compared to DSS-controls (p < .001). Conclusions: Emu Oil attenuated clinically- and histologically-assessed disease severity in a mouse model of chronic UC. Emu Oil demonstrates promise as an adjunct to conventional treatment options for UC management.

Intestinal homeostasis is restored in mice following a period of intestinal growth induced by orally administered Emu Oil

Previously, we reported that orally administered Emu Oil (EO) increases mucosal thickness in the small intestine and colon in rodent models of chemotherapy-induced mucositis and colitis. However, it remains unclear whether mucosal thickening (crypt and villus lengthening) represents a process of normal or aberrant growth. We sought to determine if villus height (VH) and crypt depth (CD) measurements returned to normal in EO-treated rats following withdrawal of EO therapy. Dark agouti rats ( n = 8/group) were gavaged daily for 10 days with water, olive oil (OO), or EO (0.5 mL or 1 mL). Groups of rats were euthanized on days 10 and 17. Intestinal weights, lengths, VH, and CD were quantified. P < 0.05 was considered significant. On day 10, jejuno-ileum weight was increased by OO (26%) and EO (0.5 mL: 15%; 1 mL: 29%) compared to water controls ( P < 0.01), which was normalized by day 17. On days 10 and 17, jejuno-ileum length was greater in OO- (12%) and EO-treated rats (0.5 mL: 8%; 1 mL: 12%; P < 0.05), relative to water controls. On day 10, OO and EO increased ileal VH (OO: 32%; 0.5 EO: 22%; EO: 35%; P < 0.01) and CD (OO: 17%; 0.5 EO: 13%; EO: 22%) compared to water controls. Importantly, however, after withdrawal of all oils, VH and CD measurements returned to normal control values. Moreover, the VH:CD ratio (potential indicator of dysplasia) remained unchanged in all experimental groups on days 10 and 17. The restoration of normal intestinal architecture following cessation of Emu Oil therapy supports its safety for application in intestinal disorders. Impact statement Uncontrolled inflammation and intestinal proliferation can predispose to the development of colorectal cancer. In previous pre-clinical studies, we demonstrated that oral administration of Emu Oil promotes intestinal repair via stimulation of the mucosa in response to tissue injury and inflammation. Therefore, it was important to determine if Emu Oil administration did not promote the precocious development of colorectal cancer. The current study revealed that Emu Oil returned indicators of intestinal proliferation back to normal values after a period of seven days. These data strongly support the safety of Emu Oil for further studies in the context of bowel inflammation.

Female rats display fewer optimistic responses in a judgment bias test in the absence of a physiological stress response

Metabolic cages are a type of housing used in biomedical research. Metabolic cage housing has been demonstrated to elicit behavioural and physiological changes in rodents housed within them. The nature of this effect has been characterized as anxiogenic. However, few studies have evaluated positive affect in response to metabolic cage housing and the interaction between this, sex and traditional physiological measures of stress. Cognitive biasing, as measured through a judgment bias paradigm has proven a reliable measure of animal affective state, particularly through its ability to measure positive affect. The current study investigated differences in cognitive biasing between male and female rats when transferred from open-top, grouped housing to a metabolic cage. Rats (Rattus norvegicus) (n=60) were trained in a judgment bias paradigm previously validated for use in the rat model. Upon exposure to an intermediate, ambiguous probe rats responded with either an optimistic or pessimistic decision. The animals were also subjected to the sucrose preference test to identify the presence of anhedonia. Faecal corticosterone and changes in adrenal tyrosine hydroxylase were also measured to establish whether a stress-like state was experienced. There was a significant interaction between sex and metabolic cage housing on the number of optimistic decisions made F (1, 56)=7.461, p=0.008. Female rats that remained in control housing responded with a reduced number of days featuring an optimistic decision compared to males in control housing (p=0.036). However, both males and females responded with significantly fewer optimistic decisions in the metabolic cage compared to control (p<0.001). There was a significant negative correlation between treatment and sucrose consumption (rpb=-0.654, n=195, p<0.001). There was also a significant sex effect for faecal corticosterone concentrations F (1, 30)=6.305, p=0.018) with female rats (4.050±1.285), displaying greater corticosterone concentrations than males (2.291±0.495). No differences between treatment were observed for either corticosterone or tyrosine hydroxylase levels. This data demonstrates that movement into a metabolic cage resulted in rats displaying significantly greater pessimistic cognitive biases as determined through the judgment bias test. Interestingly, male rats that remained in control housing demonstrated cognitive biases that were not equivalent to female rats. Furthermore, despite a behavioural change being evident, a physiological change in corticosterone or tyrosine hydroxylase levels was not observed.