Effects of Ovariohysterectomy and Hyperbaric Oxygen Therapy on Systemic Inflammation and Oxidation in Dogs

The effects of hyperbaric oxygen therapy on snake-bite-associated wounds in dogs

OBJECTIVE

To assess the effect of hyperbaric oxygen therapy (HBOT) on Crotalinae envenomation-induced wound swelling and severity and pain in dogs, and to describe the safety and complications of HBOT.

DESIGN

Prospective, randomized, controlled, blinded study (2017-2021).

SETTING

University teaching hospital, private veterinary practice.

ANIMALS

Thirty-six client-owned dogs presenting within 24 hours of a confirmed or suspected naturally occurring Crotalinae snake bite injury were enrolled between 2017 and 2021.

INTERVENTIONS

In addition to the standard of care treatment, dogs received 2 interventions with either HBOT (n = 19) or control (n = 16) within 24 hours of hospital admission. Dogs receiving HBOT were pressurized over 15 minutes (1 psi/min), maintained at a target pressure of 2 atmosphere absolute (ATA) for 30 minutes, and decompressed over 15 minutes. Control dogs received 1 ATA for 1 hour. Local wound swelling, wound severity score, and pain score were assessed at admission, before and after each intervention, and at hospital discharge.

MEASUREMENTS AND MAIN RESULTS

There was no significant difference in wound swelling (P = 0.414), severity score (P = 1.000), or pain score (P = 0.689) between HBOT and control groups. Pain decreased significantly over time regardless of the study intervention (P < 0.001). There were no major adverse effects associated with either study intervention.

CONCLUSIONS

HBOT did not significantly alter the short-term recovery from Crotalinae envenomation in this study population. However, the study might be underpowered to detect a significant treatment effect.

Hyperbaric Oxygen Therapy Attenuated the Motor Coordination and Cognitive Impairment of Polyglutamine Spinocerebellar Ataxia SCA17 Mice

Spinocerebellar ataxias (SCAs) are a large and diverse group of autosomal-dominant neurodegenerative diseases. No drugs have been approved for these relentlessly progressive and fatal SCAs. Our previous studies indicate that oxidative stress, neuroinflammation, and neuronal apoptosis are elevated in the SCA17 mice, which are the main therapeutic targets of hyperbaric oxygen treatment (HBOT). HBOT is considered to be an alternative and less invasive therapy for SCAs. In this study, we evaluated the HBOT (2.2 ATA for 14 days) effect and the persistence for the management of SCA17 mice and their wild-type littermates. We found HBOT attenuated the motor coordination and cognitive impairment of SCA17 mice and which persisted for about 1 month after the treatment. The results of several biochemistry and liver/kidney hematoxylin and eosin staining show the HBOT condition has no obvious toxicity in the mice. Immunostaining analyses show that the neuroprotective effect of HBOT could be through the promotion of BDNF production and the amelioration of neuroinflammation. Surprisingly, HBOT executes different effects on the male and female SCA17 mice, including the reduction of neuroinflammation and activation of CaMKII and ERK. This study suggests HBOT is a potential alternative therapeutic treatment for SCA17. Accumulated findings have revealed the similarity in disease pathomechanisms and possible therapeutic strategies in polyQ diseases; therefore, HBOT could be an optional treatment as well as the other polyQ diseases.

Common Uses and Adverse Effects of Hyperbaric Oxygen Therapy in a Cohort of Small Animal Patients: A Retrospective Analysis of 2,792 Treatment Sessions

Hyperbaric oxygen therapy (HBOT) is commonly utilized for various human conditions with a low incidence of major adverse effects (0.002–0.035%). Despite growing use in veterinary patients, there remains a paucity of literature describing its use and associated complications. The purpose of this study was to report clinical use of HBOT in small animals and identify the rate of major adverse events at a university teaching hospital. Electronic medical records were searched for small animals receiving HBOT between November 2012 and February 2020. Data extracted from the medical records included signalment, treatment indication, and adverse events. Treatment sessions totaled 2,792 in 542 dogs, 24 cats, and 10 pocket pets and exotics. Common indications included neurologic injuries (50.4%), tissue healing (31.4%), control of oomycete infection (5.5%), neoplasia or post-radiation injury (5.4%), and various miscellaneous conditions (7.4%). Observed minor adverse events included agitation in two dogs and vomiting in three dogs. The most common major adverse event was central nervous system (CNS) oxygen toxicity in 19 dogs. Central nervous system oxygen toxicity, manifesting as focal or generalized seizures, occurred in 0.7% of treatment sessions, with increasing age (p = 0.01) and female sex (p = 0.01) identified as risk factors. One dog developed pulmonary edema following HBOT which is a reported adverse event in humans or may have been a manifestation of progression of the dog's underlying disease. No adverse events were noted in cats or other species. In conclusion, HBOT appeared safe across various indications, although oxygen toxicity affecting the CNS was higher than reports in humans. Future prospective, randomized, controlled trials should evaluate specific clinical indications and outcomes.

Spectrophotometric assays for evaluation of Reactive Oxygen Species (ROS) in serum: general concepts and applications in dogs and humans

Reactive oxygen species (ROS) are reactive compounds derived from oxygen. In biological systems, an excessive amount of ROS can cause oxidative damage to biological macromolecules being involved in different diseases. Several assays have been developed in the last 30 years for ROS evaluation. The objective of this article will be to provide an update about the spectrophotometric methods currently used in the assessment of ROS in serum. The chemical basis of four different techniques will be reviewed, and examples of their possible applications will be provided. A particular emphasis about the practical applications of these assays in the dog will be made, but selected information about their use in humans will also be presented for comparative purposes, following a One-Health approach. The information about the spectrophotometric assays presented in this paper should be interpreted with caution once limited information about them is available yet, and further studies should be performed to clarify what they measure and their clinical application. Ideally, when applied to evaluate a sample's oxidative status, they should be incorporated in a panel of analytes where other oxidants, antioxidants, and biomarkers of inflammation were also included.

Kinetics of Plasma Cytokines, Angiopoietin-2, and C-Reactive Protein in Dogs With Gastric Dilatation Volvulus

Background: The degree of systemic inflammation, reperfusion injury and endothelial activation are potentially important determinants of clinical outcomes in dogs with gastric dilatation volvulus (GDV).

Objective: To evaluate plasma concentrations and kinetics of inflammatory markers in dogs with GDV over a time frame of 48 h, and to compare to healthy dogs.

Design and Setting: Prospective, observational cohort study in client-owned dogs with GDV.

Materials and Methods: Fifteen dogs with GDV and 9 healthy control dogs were enrolled. Plasma concentrations of interleukin (IL)-6, IL-7, IL-8, IL-10, IL-15, IL-18, interferon gamma (IFN-γ), keratinocyte chemotactic-like, monocyte chemotactic protein (MCP)-1, Angiopoietin (Ang)-2, and C-reactive protein (CRP) were measured at admission (prior any therapeutic intervention, (T0), immediately after surgery (T1), 24 ± 4 h (T24), and 48 ± 4 h (T48) post-surgery. Cytokines were measured using multiplex magnetic bead assay. Plasma Ang-2 was measured with a commercial human ELISA test kit validated for dogs.

Results: Dogs with GDV had significantly higher plasma concentrations of IFN-γ and IL-10 compared to healthy control dogs at all time points. Concentrations of IL-6 were significantly higher at T1 and T24, concentrations of MCP-1 at T24, and concentrations of CRP at T24 and T48. A significant increase between T0 and T1 was found for IL-6, IL-10, and CRP, between T1 and T24 for IL-8, IFN-γ, MCP-1, and CRP, and between T24 and T48 for IL-15, Ang-2, and CRP. A significant decrease between T0 and T1 was found for IL-7, IL-8, IL-15, IL-18, and Ang-2; between T1 and T24 for IL-6 and KC-like; and between T24 and T48 for IL-6.

Conclusion: In GDV dogs, a mild pro-inflammatory reaction was present at admission, which peaked immediately after and up to 24 h post-surgery, mainly represented by IL-6, IFN-γ, MCP-1, and CRP, and which decreased at T48. In addition, the anti-inflammatory IL-10 was increased in GDV dogs at all time points.

Acute Effects on the Human Peripheral Blood Transcriptome of Decompression Sickness Secondary to Scuba Diving

Decompression sickness (DCS) develops due to inert gas bubble formation in bodily tissues and in the circulation, leading to a wide range of potentially serious clinical manifestations. Its pathophysiology remains incompletely understood. In this study, we aim to explore changes in the human leukocyte transcriptome in divers with DCS compared to closely matched unaffected controls after uneventful diving. Cases (n = 7) were divers developing the typical cutis marmorata rash after diving with a confirmed clinical diagnosis of DCS. Controls (n = 6) were healthy divers who surfaced from a ≥25 msw dive without decompression violation or evidence of DCS. Blood was sampled at two separate time points-within 8 h of dive completion and 40-44 h later. Transcriptome analysis by RNA-Sequencing followed by bioinformatic analysis was carried out to identify differentially expressed genes and relate their function to biological pathways. In DCS cases, we identified enrichment of transcripts involved in acute inflammation, activation of innate immunity and free radical scavenging pathways, with specific upregulation of transcripts related to neutrophil function and degranulation. DCS-induced transcriptomic events were reversed at the second time point following exposure to hyperbaric oxygen. The observed changes are consistent with findings from animal models of DCS and highlight a continuum between the responses elicited by uneventful diving and diving complicated by DCS. This study sheds light on the inflammatory pathophysiology of DCS and the associated immune response. Such data may potentially be valuable in the search for novel treatments targeting this disease.

The effects of melatonin treatment on oxidative stress induced by ovariohysterectomy in dogs

BACKGROUND

As one of the most common surgeries performed in veterinary medicine, ovariohysterectomy (OHE) can induce oxidative stress in dogs. The antioxidant properties of melatonin have been confirmed in various studies. This study aimed to investigate the effects of melatonin administration on oxidative stress in dogs before and after OHE. In this study, 25 mature female intact dogs were selected and randomly divided into five equal groups: Melatonin (melatonin, no surgery), OHE (no melatonin, surgery), OHE + melatonin (melatonin, surgery), anesthesia+melatonin (melatonin, sham surgery), and control (no melatonin, no surgery) groups. Melatonin (0.3 mg/Kg/day, p.o.) was administrated to the dogs in the melatonin, OHE + melatonin, and anesthesia+melatonin groups on days - 1, 0, 1, 2, and 3 (day 0 = OHE). Blood sampling was performed on days - 1, 1, 3, and 5 of the study. Blood samples were immediately transferred to the laboratory and sera were separated and stored at - 20 °C. Superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT) and malondialdehyde (MDA) concentrations were measured with commercial kits.

RESULTS

The levels of SOD, GPX and CAT were significantly higher in the melatonin and anesthesia+melatonin groups compared to those of the control group at days 3 and 5. The level of antioxidant enzymes significantly decreased in the OHE group compared to that of other groups at days 3 and 5. The administration of melatonin increased the level of antioxidant enzymes in ovariohysterectomized dogs. Ovariohysterectomy significantly increased the concentration of MDA in comparison to that of other groups at day 3. Melatonin administration significantly decreased the level of MDA in melatonin, anesthetized, and ovariohysterectomized dogs at day 3.

CONCLUSIONS

Administration of melatonin on day - 1, 0, 1, 2 and 3 modulate the oxidative stress induced by OHE in dogs by increasing antioxidant enzymes concentration and decreasing MDA levels.