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OBJECTIVE: To describe the treatment and outcome of a foal with a fresh allogenic cancellous bone graft after surgical debridement of a traumatic septic osteitis. ANIMAL: A neonatal Quarter Horse foal. STUDY DESIGN: Case report. METHODS: The foal sustained a traumatic laceration exposing the proximal third metatarsal bone. One week after surgical debridement and closure, radiographic signs of septic osteitis were noted along the physeal scar. The lesion was debrided, and antimicrobial therapy was implemented. The infection resolved but left a large defect in the metaphysis and epiphysis. Grafting was indicated to avoid pathologic fractures of the plantar and proximal cortices. Due to a discrepancy between defect size and the bone stock of the foal, an allogeneic cancellous bone graft was harvested from the dam's tuber coxae and used to fill the foal's defect. RESULTS: No adverse reactions to the graft were noted. After 1 month, the wound had healed. Radiographic examination was consistent with graft incorporation in the bone structure. The foal was sound at a walk and trot when examined at 6, 12, and 21 months. The bone's contour was even and its structure homogeneously radio dense. The surgical site of the mare healed without complications. CONCLUSION: Fresh allogenic cancellous bone grafting resulted in the healing of a large traumatic-septic bone defect in a foal, with an excellent functional and cosmetic outcome. For future use, compatibility testing should be considered prior to allogeneic bone grafting.
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Transplante de Células-Tronco Hematopoéticas , Doenças dos Cavalos , Ossos do Metatarso , Osteíte , Cavalos , Animais , Feminino , Osso Esponjoso/transplante , Cicatriz/veterinária , Metatarso , Osteíte/veterinária , Epífises , Transplante de Células-Tronco Hematopoéticas/veterinária , Transplante Ósseo/veterinária , Doenças dos Cavalos/cirurgiaRESUMO
BACKGROUND: Ischaemic postconditioning (IPoC) refers to brief periods of reocclusion of blood supply following an ischaemic event. This has been shown to ameliorate ischaemia reperfusion injury in different tissues, and it may represent a feasible therapeutic strategy for ischaemia reperfusion injury following strangulating small intestinal lesions in horses. The objective of this study was to assess the degree cell death, inflammation, oxidative stress, and heat shock response in an equine experimental jejunal ischaemia model with and without IPoC. METHODS: In this randomized, controlled, experimental in vivo study, 14 horses were evenly assigned to a control group and a group subjected to IPoC. Under general anaesthesia, segmental ischaemia with arterial and venous occlusion was induced in 1.5 m jejunum. Following ischaemia, the mesenteric vessels were repeatedly re-occluded in group IPoC only. Full thickness intestinal samples and blood samples were taken at the end of the pre-ischaemia period, after ischaemia, and after 120 min of reperfusion. Immunohistochemical staining or enzymatic assays were performed to determine the selected variables. RESULTS: The mucosal cleaved-caspase-3 and TUNEL cell counts were significantly increased after reperfusion in the control group only. The cleaved-caspase-3 cell count was significantly lower in group IPoC after reperfusion compared to the control group. After reperfusion, the tissue myeloperoxidase activity and the calprotectin positive cell counts in the mucosa were increased in both groups, and only group IPoC showed a significant increase in the serosa. Tissue malondialdehyde and superoxide dismutase as well as blood lactate levels showed significant progression during ischaemia or reperfusion. The nuclear immunoreactivity of Heat shock protein-70 increased significantly during reperfusion. None of these variables differed between the groups. The neuronal cell counts in the myenteric plexus ganglia were not affected by the ischaemia model. CONCLUSIONS: A reduced apoptotic cell count was found in the group subjected to IPoC. None of the other tested variables were significantly affected by IPoC. Therefore, the clinical relevance and possible protective mechanism of IPoC in equine intestinal ischaemia remains unclear. Further research on the mechanism of action and its effect in clinical cases of strangulating colic is needed.
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Apoptose , Pós-Condicionamento Isquêmico/veterinária , Jejuno/irrigação sanguínea , Traumatismo por Reperfusão/veterinária , Animais , Proteínas de Choque Térmico HSP70/metabolismo , Cavalos , Mucosa Intestinal/metabolismo , Pós-Condicionamento Isquêmico/métodos , Jejuno/patologia , Ácido Láctico/sangue , Malondialdeído/metabolismo , Traumatismo por Reperfusão/terapia , Superóxido Dismutase/metabolismoRESUMO
OBJECTIVES: The lateral trochlear ridge (LTR) of the femur is the most common predilection site for osteochondritis dissecans (OCD) in the equine stifle. The objective was to investigate the relationship between lesion size, racing performance, and sale result of Thoroughbreds with LTR OCD following arthroscopic removal as a yearling. METHODS: In this retrospective study, medical records of 145 Thoroughbreds from one equine hospital that underwent surgery for LTR OCD were reviewed; the length and depth of the lesions were measured on preoperative radiographs. Horses were allocated to group S if they were presented to a public yearling sale post-surgery, and horses in group NS were not. Each horse from group S was matched with two control horses from the same sale (group C). Influence of lesion size on racing performance and sale result was analyzed. Racing performance and sale results were compared between different categories of OCD lesion sizes and between the groups. RESULTS: Lesion length and depth did not affect racing performance and did not differ between group S and group NS. However, group S did perform significantly better than group NS. When comparing groups S and C, there were no significant differences in racing performance and sale result. CONCLUSION: Thoroughbreds that had arthroscopic surgery for LTR OCD as a yearling and were presented on a public yearling sale performed comparable to Thoroughbreds that showed similar potential as a yearling. Sale result is not significantly affected in our study.
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Doenças dos Cavalos , Osteocondrite Dissecante , Animais , Cavalos , Estudos Retrospectivos , Articulações , Osteocondrite Dissecante/cirurgia , Osteocondrite Dissecante/veterinária , Artroscopia/veterinária , Fêmur/patologia , Doenças dos Cavalos/cirurgiaRESUMO
OBJECTIVE: To evaluate the use of laser Doppler flowmetry and spectrophotometry (LDFS) for large intestinal viability assessment in horses with naturally occurring large intestinal strangulations. METHODS: By use of LDFS, intestinal microperfusion was quantified as tissue oxygen saturation (tSo2), hemoglobin (tHB), and blood flow (tBF) in cases with large colon volvulus and small colon strangulations undergoing colic surgery (n = 17). Intestinal biopsies were taken from the pelvic flexure in all large colon cases and in small colon cases that underwent intraoperative euthanasia. Measurements were compared between survivors and nonsurvivors, and the correlation between LDFS and (immuno)histology was tested (P < .05). RESULTS: The tSo2 and tBF were clearly lower and tHB was higher than previously reported in healthy horses. Following correction of the lesion, pelvic flexure tBF was significantly lower than that of the left ventral colon. Prior to correction of the lesion, microperfusion did not differ between survivors and nonsurvivors, but following release of the strangulation the survivors had a significantly higher tSo2 and tBF compared to the nonsurvivors. There was a negative correlation between tBF and interstitium-to-crypt ratio and a positive correlation between tHB and the histological hemorrhage score. There were no significant correlations between LDFS measurements and inflammatory cell counts or hypoxia-inducible factor-1α immunoreactivity. CONCLUSIONS: Large intestinal microperfusion was decreased in nonsurvivors compared to survivors and was correlated with histological injury, suggesting that LDFS has the potential to predict tissue injury and postoperative survival. CLINICAL RELEVANCE: The use of LDFS as an ancillary diagnostic aid may improve intraoperative viability assessment during colic surgery.
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BACKGROUND: Ancillary diagnostic methods to enhance the accuracy of viability assessment have not been established for use in clinical practice. OBJECTIVES: To assess intestinal microperfusion measured by Laser Doppler Flowmetry and Spectrophotometry (LDFS) in naturally occurring small intestinal strangulations of different origins and to compare this between viable and non-viable segments. STUDY DESIGN: Prospective clinical trial. METHODS: Forty horses undergoing colic surgery for naturally occurring small intestinal strangulations were included. Tissue oxygen saturation (tSO2), haemoglobin (tHB) and blood flow (tBF) were determined by LDFS before and after release of the strangulation. Intestinal biopsies were taken in cases that underwent intestinal resection or intraoperative euthanasia and assessed using a semi-quantitative mucosal injury score (MIS). The LDFS measurements were compared between the different categories of strangulation causes and histopathological injury using parametric and non-parametric tests (p < 0.05). RESULTS: Strangulations by pedunculated lipomas had lower tBF (13.9 ± 18 arbitrary units [AU]) than epiploic foramen entrapments (65.2 ± 61 AU; CI -1.697 to -0.2498; p = 0.005). Segments with MIS > 5 showed lower tBF during strangulation than segments with MIS < 4 (mean difference 61.1 AU; CI -1.119 to -0.07361; p = 0.03). This did not differ significantly following release of strangulation. Furthermore, there was a positive correlation between the inflammatory cell count and tBF during strangulation (r 0.34; CI 0.01 to 0.60; p = 0.04). The tSO2 and tHB did not differ between the different categories of lesions or injury. MAIN LIMITATIONS: No biopsies could be taken from the intestinal segments that did not undergo resection. The duration of strangulation could not reliably be ascertained. CONCLUSIONS: Blood flow measurements in naturally occurring strangulating lesions show a varying degree of ischaemia in different causes of strangulation. Intestinal blood flow measurements prior to release of the strangulation could potentially contribute to the identification of mucosal injury, yet a high individual variability and other contributing factors need to be considered.
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OBJECTIVE: To assess the histological injury and intestinal microperfusion measured by laser Doppler flowmetry and spectrophotometry (LDFS) of the small intestine orad to a strangulation during colic surgery. ANIMALS: Horses with naturally occurring small intestinal strangulations undergoing colic surgery were included. METHODS: In this prospective clinical trial, intestinal tissue oxygen saturation (tSO2) and tissue blood flow (tBF) were measured by LDFS orad to the strangulation following release of the strangulation (n = 18). The number of horses with postoperative reflux (POR) and the cases that survived until discharge were compared between groups using Fisher's exact test (P < .05). Intestinal biopsies were taken in cases that underwent intestinal resection or intraoperative euthanasia (n = 28). Measurements were compared between injured and noninjured segments with a Mann-Whitney U or t test. RESULTS: The tSO2 and tBF of the orad intestine were lower than previously reported in healthy horses. Horses with low tSO2 of < 35% were significantly more likely to suffer from POR (6/6 cases) compared to cases with tSO2 > 69% (1/6). The number of horses that survived were not statistically different between these groups (2/6 and 6/6). All horses with mucosal injury developed POR (6/6), which was significantly more likely compared to horses without mucosal injury (3/13). No significant difference in tSO2 or tBF could be found between the segments with and without histological injury. CLINICAL RELEVANCE: The results suggest that measuring tSO2 in the orad segment during colic surgery may aid in predicting postoperative issues.
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Cólica , Doenças dos Cavalos , Complicações Pós-Operatórias , Animais , Cavalos , Doenças dos Cavalos/cirurgia , Doenças dos Cavalos/metabolismo , Cólica/veterinária , Cólica/cirurgia , Complicações Pós-Operatórias/veterinária , Feminino , Masculino , Estudos Prospectivos , Íleus/veterinária , Saturação de Oxigênio , Fluxometria por Laser-Doppler/veterinária , Oxigênio/metabolismo , Intestino Delgado/cirurgia , Espectrofotometria/veterináriaRESUMO
Pharmacological preconditioning with dexmedetomidine has been shown to ameliorate intestinal ischaemia reperfusion injury in different species, including horses. However, it remains unknown if this effect is related to alpha2 adrenoreceptor activity. Therefore, the aim of this study was to determine the effect of dexmedetomidine preconditioning with and without the administration of the peripheral alpha2 antagonist vatinoxan. This prospective randomized experimental trial included 12 horses equally divided between two treatment groups. Horses in group Dex received a bolus of dexmedetomidine followed by a continuous rate infusion (CRI), while group DexV additionally received vatinoxan as bolus and CRI. A median laparotomy was performed under general anaesthesia, and jejunal ischaemia was applied for 90 min, followed by 30 min of reperfusion. Mucosal damage was evaluated in full thickness biopsies by use of a semiquantitative mucosal injury score and by determining the apoptotic cell counts with immunohistochemical staining for cleaved caspase-3 and TUNEL. Comparisons between the groups and time points were performed using non-parametric tests (p < 0.05). During pre-ischaemia and ischaemia, no differences could be found in mucosal injury between the groups. After reperfusion, group DexV showed lower mucosal injury scores compared to group Dex. The apoptotic cell counts did not differ between the groups. In conclusion, antagonizing the peripheral alpha2 adrenoreceptors did not negatively affect dexmedetomidine preconditioning.
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α2 agonists are frequently used in horses with colic, even though they have been shown to inhibit gastrointestinal motility. The aim of this study was to determine the effect of dexmedetomidine on small intestinal in vitro contractility during different phases of ischaemia. Experimental segmental jejunal ischaemia was induced in 12 horses under general anaesthesia, and intestinal samples were taken pre-ischaemia and following ischaemia and reperfusion. Spontaneous and electrically evoked contractile activity of the circular and longitudinal smooth muscles were determined in each sample with and without the addition of dexmedetomidine. During a second experiment, tetrodotoxin was added to determine if the effect was neurogenic. We found that the circular smooth muscle (CSM) contractility was not affected by ischaemia, whereas the longitudinal smooth muscle (LSM) showed an increase in both spontaneous and induced contractile activity. The addition of dexmedetomidine caused a decrease in the spontaneous contractile activity of CSM, but an increase in that of LSM, which was not mediated by the enteric nervous system. During ischaemia, dexmedetomidine also mildly increased the electrically induced contractile activity in LSM. These results may indicate a stimulatory effect of dexmedetomidine on small intestinal contractility. However, the influence of dexmedetomidine administration on intestinal motility in vivo needs to be further investigated.
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Introduction: Hypoxia inducible factors (HIF) are widely researched in human medicine for their role in different disease processes. The aim of this study was to investigate the expression and distribution of HIF in experimental small intestinal ischemia in the horse. Methods: In 14 horses under general anesthesia, segmental jejunal ischemia with 90% reduction in blood flow was induced. The horses were randomly divided into two groups of seven horses, one subjected to ischemic postconditioning (IPoC) by delayed reperfusion, and a control group (group C) undergoing undelayed reperfusion. Intestinal samples were taken pre-ischemia, after ischemia and after reperfusion. Following immunohistochemical staining for HIF1α and -2α, the immunoreactivity pattern in the small intestine was evaluated by light microscopy, and the mucosal enterocyte and muscularis staining were semi-quantitatively scored. Additionally, mucosal HIF1α protein levels were determined by an Enzyme Linked Immunosorbent Assay (ELISA), and mRNA levels of HIF1α and its target genes by a two-step real-time Reverse Transcriptase Polymerase Chain Reaction. Statistical comparison was performed between the groups and time points using parametric and non-parametric tests (p < 0.05). Results: All cell types exhibited cytoplasmic and nuclear immunoreactivity for HIF1α. After reperfusion, the cytoplasmic staining of the crypt and villus enterocytes as well as the villus nuclear staining significantly increased, whereas the perinuclear granules in the crypts decreased. The protein levels showed a significant decrease in group C at reperfusion, with lower HIF1α levels in group C compared to group IPoC during ischemia and reperfusion. No other group differences could be detected. In the HIF2α stained slides, mild to moderate cytoplasmic staining yet no nuclear immunoreactivity of the enterocytes was observed, and no significant changes over time were noted. Discussion: the changes in HIF1α immunoreactivity pattern and expression over time suggest that this transcription factor plays a role in the intestinal response to ischemia in horses. However, the current study could not identify an effect of IPoC on HIF distribution or expression.
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CASE SUMMARY: A two-year-old donkey presented with recurrent syncope. Electrocardiography revealed periods without any atrioventricular conduction and without any ventricular escape rhythm with a duration of up to one minute. Finally, atrioventricular conduction resumed spontaneously with a preceding ventricular escape beat. Laboratory tests and echocardiography identified no reversible cause. The diagnosis of a paroxysmal atrioventricular block (PAVB) was made. Therefore, a single-chamber cardiac pacemaker was implanted under general anesthesia. The device was programmed in the VVI mode to prevent further syncope. The therapy was considered successful as the donkey revealed no further syncope during the follow-up period of 17 months. CLINICAL RELEVANCE: Clinically relevant bradycardia is rare in equids. This is the first report to our knowledge to describe a PAVB, a term commonly used in human medicine, in a donkey. Detailed information about the diagnosis and the successful therapy is included, with a special focus on the implantation and programming of the permanent pacemaker.
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Intestinal ischemia reperfusion injury (IRI) is a frequent complication of equine colic. Several mechanisms may be involved in adaptation of the intestinal epithelium to IRI and might infer therapeutic potential, including hypoxia-inducible factor (HIF) 1α, AMP-activated protein kinase (AMPK), nuclear factor-erythroid 2-related factor 2 (NRF2), and induction of autophagy. However, the mechanisms supporting adaptation and thus cellular survival are not completely understood yet. We investigated the activation of specific adaptation mechanisms in both no and low flow ischemia and reperfusion simulated in equine jejunum epithelium in vivo. We found an activation of HIF1α in no and low flow ischemia as indicated by increased levels of HIF1α target genes and phosphorylation of AMPKα tended to increase during ischemia. Furthermore, the protein expression of the autophagy marker LC3B in combination with decreased expression of nuclear-encoded mitochondrial genes indicates an increased rate of mitophagy in equine intestinal IRI, possibly preventing damage by mitochondria-derived reactive oxygen species (ROS). Interestingly, ROS levels were increased only shortly after the onset of low flow ischemia, which may be explained by an increased antioxidative defense, although NFR2 was not activated in this setup. In conclusion, we could demonstrate that a variety of adaptation mechanisms manipulating different aspects of cellular homeostasis are activated in IRI irrespective of the ischemia model, and that mitophagy might be an important factor for epithelial survival following small intestinal ischemia in horses that should be investigated further.
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In experimental studies investigating strangulating intestinal lesions in horses, different ischaemia models have been used with diverging results. Therefore, the aim was to comparatively describe ischaemia reperfusion injury (IRI) in a low flow (LF) and no flow (NF) model. Under general anaesthesia, 120 min of jejunal ischaemia followed by 120 min of reperfusion was induced in 14 warmbloods. During ischaemia, blood flow was reduced by 80% (LF, n = 7) or by 100% (NF, n = 7). Intestinal blood flow and oxygen saturation were measured by Laser Doppler fluxmetry and spectrophotometry. Clinical, histological, immunohistochemical and Ussing chamber analyses were performed on intestinal samples collected hourly. Tissue oxygen saturation was significantly lower in NF ischaemia. The LF group exhibited high variability in oxygen saturation and mucosal damage. Histologically, more haemorrhage was found in the LF group at all time points. Cleaved-caspase-3 and calprotectin-stained cells increased during reperfusion in both groups. After NF ischaemia, the tissue conductance was significantly higher during reperfusion. These results aid in the selection of suitable experimental models for future studies. Although the LF model has been suggested to be more representative for clinical strangulating small intestinal disease, the NF model produced more consistent IRI.
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High-definition oscillometry (HDO) over the metatarsal artery (MA) in anaesthetised horses has not yet been evaluated. This study aimed to assess agreement between HDO and invasive blood pressure (IBP) at the metatarsal artery, and to evaluate compliance with the American College of Veterinary Internal Medicine (ACVIM) consensus guidelines. In this experimental study, 11 horses underwent general anaesthesia for an unrelated, terminal surgical trial. Instrumentation included an IBP catheter in one and an HDO cuff placed over the contralateral MA, as well as thermodilution catheters. Systolic arterial pressure (SAP), mean arterial pressure (MAP), diastolic arterial pressure (DAP), and cardiac output were measured simultaneously. Normotension (MAP 61-119 mmHg) was maintained during the surgical study. Subsequently, hypotension (MAP ≤ 60 mmHg) and hypertension (MAP ≥ 120 mmHg) were induced pharmacologically. For MAP, the agreement between HDO and IBP was acceptable during normotension, while during hypotension and hypertension, IBP was overestimated and underestimated by HDO, respectively. The monitor failed to meet most ACVIM validation criteria. Consequently, if haemodynamic compromise or rapid blood pressure changes are anticipated, IBP remains preferable.
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BACKGROUND: Ischaemic postconditioning (IPoC) has been shown to ameliorate ischaemia reperfusion injury in different species and tissues. OBJECTIVES: To assess the feasibility of IPoC in equine small intestinal ischaemia and to assess its effect on histomorphology, electrophysiology and paracellular permeability. STUDY DESIGN: Randomised in vivo experiment. METHODS: Experimental jejunal ischaemia was induced for 90 min in horses under general anaesthesia. In the control group (C; n = 7), the jejunum was reperfused without further intervention. In the postconditioning group (IPoC; n = 7), reocclusion was implemented following release of ischaemia by clamping the mesenteric vessels in three cycles of 30 seconds. This was followed by 120 minutes of reperfusion in both groups. Intestinal microperfusion and oxygenation was measured during IPoC using spectrophotometry and Doppler flowmetry. Histomorphology and histomorphometry of the intestinal mucosa were assessed. Furthermore, electrophysiological variables and unidirectional flux rates of 3 H-mannitol were determined in Ussing chambers. Western blot analysis was performed to determine the tight junction protein levels of claudin-1, claudin-2 and occludin in the intestinal mucosa. Comparisons between the groups and time points were performed using a two-way repeated measures analysis of variance (ANOVA) or non-parametric statistical tests for the ordinal and not normally distributed data (significance P < .05). RESULTS: IPoC significantly reduced intestinal microperfusion during all clamping cycles yet affected oxygen saturation only during the first cycle. After reperfusion, Group IPoC showed significantly less mucosal villus denudation (mean difference 21.5%, P = .02) and decreased mucosal-to-serosal flux rates (mean difference 15.2 nM/cm2 /h, P = .007) compared to Group C. There were no significant differences between the groups for the other tested variables. MAIN LIMITATIONS: Small sample size, long-term effects were not investigated. CONCLUSIONS: Following IPoC, the intestinal mucosa demonstrated significantly less villus denudation and paracellular permeability compared to the untreated control group, possibly indicating a protective effect of IPoC on ischaemia reperfusion injury.
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Doenças dos Cavalos , Pós-Condicionamento Isquêmico , Traumatismo por Reperfusão , Animais , Doenças dos Cavalos/prevenção & controle , Cavalos , Intestino Delgado , Isquemia/veterinária , Pós-Condicionamento Isquêmico/veterinária , Jejuno , Traumatismo por Reperfusão/prevenção & controle , Traumatismo por Reperfusão/veterináriaRESUMO
BACKGROUND: Pharmacological preconditioning of dexmedetomidine on small intestinal ischaemia/reperfusion injury has been reported in different animal models including horses. OBJECTIVES: The objective was to assess if xylazine and lidocaine have a preconditioning effect in an experimental model of equine jejunal ischaemia. STUDY DESIGN: Terminal in vivo experiment. METHODS: Ten horses under general anaesthesia were either preconditioned with xylazine (group X; n = 5) or lidocaine (group L; n = 5). A historical untreated control group (group C; n = 5) was used for comparison. An established experimental model of equine jejunal ischaemia was applied, and intestinal samples were taken pre-ischaemia, after ischaemia and following reperfusion. Histomorphological examination was performed based on a modified Chiu score. Immunohistochemical staining for cleaved caspase-3, TUNEL and calprotectin was performed, and positive cell counts were expressed in cells/mm2 . RESULTS: There was no progression of histomorphological mucosal injury from ischaemia to reperfusion, and there were no differences in histomorphology between the groups. After ischaemia, group X had significantly less caspase-positive cells compared to the control group with a median difference of 227% (P = .01). After reperfusion, group X exhibited significantly lower calprotectin-positive cell counts compared to the control group, with a median difference of 6.8 cells/mm2 in the mucosa and 44 cells in the serosa (P = .02 and .05 respectively). All groups showed an increase in caspase- and calprotectin-positive cells during reperfusion (P < .05). TUNEL-positive cells increased during ischaemia, followed by a decrease after reperfusion (P < .05). MAIN LIMITATIONS: The small sample size and the use of a historical control group. Preconditioning effects of the tested drugs may be masked by the protective effects of isoflurane in the anaesthetic protocol. CONCLUSIONS: Preconditioning with lidocaine did not have any effect on the tested variables. The lower cell counts of caspase- and calprotectin-positive cells in group X may indicate a beneficial effect of xylazine on ischaemia/reperfusion injury. Due to the absence of a concurrent reduction of histomorphological injury, the clinical significance remains uncertain.
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Doenças dos Cavalos , Traumatismo por Reperfusão , Animais , Doenças dos Cavalos/prevenção & controle , Cavalos , Isquemia/veterinária , Lidocaína/farmacologia , Traumatismo por Reperfusão/prevenção & controle , Traumatismo por Reperfusão/veterinária , Xilazina/farmacologiaRESUMO
BACKGROUND: Strangulating small intestinal lesions in the horse have increased morbidity and mortality compared to nonstrangulating obstructions due to mucosal barrier disruption and subsequent endotoxaemia. OBJECTIVES: To investigate protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in the horse. STUDY DESIGN: Randomised, controlled, experimental study. METHODS: Eighteen systemically healthy horses were randomly assigned to three groups: control, preconditioning, and post-conditioning. During isoflurane anaesthesia, complete ischaemia was induced in a 1-m segment of jejunum for 90 minutes. Horses in the preconditioning and post-conditioning groups received dexmedetomidine (3.5 µg/kg followed by 7 µg/kg/h) before (preconditioning) or after beginning ischaemia (post-conditioning), and during reperfusion. Jejunal biopsies were collected before ischaemia (baseline-1), at the end of the ischaemic period (ischaemia), and 30 minutes after reperfusion (reperfusion-1). Additional biopsies were taken 24 hours after reperfusion from ischaemia-reperfusion-injured jejunum (reperfusion-2). Epithelial injury was scored histologically, and morphometric analyses were used to calculate villus surface area (VSA) denuded of epithelium. Data were analysed using analysis of variance, Kruskal-Wallis and Wilcoxon two-sample tests. RESULTS: In the control group, epithelial injury scores and percentage of VSA denudation for ischaemia-reperfusion-injured jejunum were higher compared to baseline-1 at all time points. The ischaemia and both reperfusion samples from the pre- and post-conditioning groups had lower epithelial injury scores and percentage of VSA epithelial denudation compared to the control group, with no difference from baseline-1 at any time point for the preconditioning group. MAIN LIMITATIONS: Preconditioning has limited application in the clinical setting with naturally occurring strangulating small intestinal lesions. CONCLUSIONS: Dexmedetomidine was protective for small intestinal ischaemia-reperfusion injury in the horse when administered before or during ischaemia.
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Dexmedetomidina , Doenças dos Cavalos , Traumatismo por Reperfusão , Animais , Dexmedetomidina/farmacologia , Doenças dos Cavalos/prevenção & controle , Cavalos , Mucosa Intestinal , Intestino Delgado , Jejuno , Traumatismo por Reperfusão/prevenção & controle , Traumatismo por Reperfusão/veterináriaRESUMO
Pain assessment is very important for monitoring welfare and quality of life in horses. To date, no studies have described pain scales for objective assessment of pain in foals. Studies in other species have shown that facial expression can be used in neonatal animals for objective assessment of acute pain. The aim of the current study was to adapt a facial expression-based pain scale for assessment of acute pain in mature horses for valid pain assessment in foals. The scale was applied to fifty-nine foals (20 patients and 39 healthy controls); animals were assessed from video recordings (30-60 s) by 3 observers, who were blinded for the condition of the animals. Patients were diagnosed with acute health problems by means of clinical examination and additional diagnostic procedures. EQUUS-FAP FOAL (Equine Utrecht University Scale for Facial Assessment of Pain in Foals) showed good inter- and intra-observer reliability (Cronbach's alpha = 0.95 and 0.98, p < 0.001). Patients had significantly higher pain scores compared to controls (p < 0.001) and the pain scores decreased after treatment with NSAIDs (meloxicam or flunixin meglumine IV) (p < 0.05). Our results indicate that a facial expression-based pain scale could be useful for the assessment of acute pain in foals. Further studies are needed to validate this pain scale.
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Small intestinal strangulation associated with ischaemia-reperfusion injury (IRI) is common in horses. In laboratory animals IRI can be ameliorated by ischaemic preconditioning (IPC) and pharmacological preconditioning (PPC) with dexmedetomidine. The aim of this study was to determine the effect of PPC with dexmedetomidine or IPC in an equine model of small intestinal ischaemia-reperfusion (IR). In a randomized controlled experimental trial, 15 horses were assigned to three groups: control (C), IPC, and PPC with dexmedetomidine (DEX). All horses were placed under general anaesthesia and 90% jejunal ischaemia was induced for 90 minutes, followed 30 minutes of reperfusion. In group IPC, three short bouts of ischaemia and reperfusion were implemented, and group DEX received a continuous rate infusion of dexmedetomidine prior to the main ischaemia. Jejunal biopsies were collected before ischaemia (P), and at the end of ischaemia (I) and reperfusion (R). Mucosal injury was assessed by the Chiu-Score, inflammatory cells were stained by cytosolic calprotectin. The degree of apoptosis and cell necrosis was assessed by cleaved-caspase-3 and TUNEL. Parametric data were analyzed by two-way ANOVA for repeated measurements followed by Dunnetts t-test. Non parametric data were compared between groups at the different time points by a Kruskal-Wallis-Test and a Wilcoxon-2-Sample-test. The mucosal injury score increased during I in all groups. After reperfusion, IRI further progressed in group C, but not in IPC and DEX. In all groups the number of cleaved caspase-3 and TUNEL positive cells increased from P to I. The number of TUNEL positive cells were lower in group DEX compared to group C after I and R. Infiltration with calprotectin positive cells was less pronounced in group DEX compared to group C, whereas in group IPC more calprotectin positive cells were seen. In conclusion, IPC and DEX exert protective effects in experimental small intestinal ischaemia in horses.
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Agonistas de Receptores Adrenérgicos alfa 2/uso terapêutico , Dexmedetomidina/uso terapêutico , Isquemia/terapia , Precondicionamento Isquêmico/métodos , Jejuno/irrigação sanguínea , Traumatismo por Reperfusão/terapia , Agonistas de Receptores Adrenérgicos alfa 2/administração & dosagem , Agonistas de Receptores Adrenérgicos alfa 2/farmacologia , Animais , Dexmedetomidina/administração & dosagem , Dexmedetomidina/farmacologia , Cavalos , Isquemia/tratamento farmacológico , Jejuno/efeitos dos fármacos , Jejuno/patologia , Distribuição Aleatória , Traumatismo por Reperfusão/tratamento farmacológicoRESUMO
In tropical and subtropical climates, infection of periocular tissue by Habronema larvae is a recognised cause of conjunctivitis or blepharitis. To the authors' knowledge, only a few cases of habronemiasis have been described in Western Europe, and it has not been documented previously in the Netherlands. The objective of this report is to describe the occurrence of five cases of (peri)ocular habronemiasis in the Netherlands, of which four date from the past few years. The diagnosis was based on the history, clinical signs and histopathologic examination of biopsy specimens. A granulomatous conjunctivitis/dermatitis and sulphur-like granules were present in all cases. Histopathology showed an eosinophilic granulomatous inflammation, and three out of five (60 per cent) samples revealed one or more nematodes on section. Treatment combinations with surgical excision, local corticosteroid and/or anthelmintic drugs were used. Furthermore, all horses received ivermectin or moxidectin. Treatment resulted in healing of the lesions in four horses. One case, which was refractory to treatment, resolved spontaneously after the onset of colder weather. This case series suggests an increased prevalence of (peri)ocular habronemiasis in the Netherlands. This diagnosis should therefore be considered when being presented with a horse with granulomatous conjunctivitis/dermatitis in Western Europe, especially during the summer months.