Cobalt chloride doping in racehorses: Concerns over a potentially lethal practice

Influence of chromium (III), cobalt (II) and their mixtures on cell metabolic activity

Chromium (III) and cobalt (II) are necessary elements required for the proper functioning of the organism, but their excess can cause toxic effects. They are the basic components of implants and are also commonly used in medicine as components of dietary supplements, vitamin and mineral products and energy drinks. The aim of this study was to investigate the effect of cobalt (II) and chromium (III) and their combination on BJ cells. In the study, BJ cells were exposed to CoCl2 or CrCl3 at concentrations ranging from 100 to 1400 µM, and the cytotoxicity of chromium (III) and cobalt (II) and their mixtures was assessed by MTT reduction, LDH release and NRU assays. The outcome of this work reveals the cytotoxic effects of chromium (III) and cobalt (II) and their mixtures on BJ cells. In the cytotoxicity assays, at low concentrations of CoCl2 and CrCl3, stimulation of cell proliferation was observed. In higher concentrations, the cell viability decreased for the tested line in all the assays. During the simultaneous incubation of fibroblasts with 200 µM of CrCl3 and 1000 µM of CoCl2, antagonism was observed: chromium (III) at the concentration of 200 µM induced protection from cobalt (II) toxicity; in the case of interaction of chromium chloride at 1000 µm and cobalt chloride at 200 µM, the protective effect of CrCl3 on CoCl2 was not observed. In the latter case, synergism between these elements was noted. Our work indicates that cobalt (II) and chromium (III) show cytotoxic properties. These metals have a destructive effect on the cell membrane, lysosomes and mitochondria, which leads to disorders of cell metabolism.

Ethanolic Extract of Moringa oleifera Leaves Influences NF-κB Signaling Pathway to Restore Kidney Tissue from Cobalt-Mediated Oxidative Injury and Inflammation in Rats

This study aimed to describe the protective efficacy of Moringa oleifera ethanolic extract (MOEE) against the impact of cobalt chloride (CoCl₂) exposure on the rat’s kidney. Fifty male rats were assigned to five equal groups: a control group, a MOEE-administered group (400 mg/kg body weight (bw), daily via gastric tube), a CoCl₂-intoxicated group (300 mg/L, daily in drinking water), a protective group, and a therapeutic co-administered group that received MOEE prior to or following and concurrently with CoCl₂, respectively. The antioxidant status indices (superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH)), oxidative stress markers (hydrogen peroxide (H₂O₂), 8-hydroxy-2-deoxyguanosine (8-OHdG), and malondialdehyde (MDA)), and inflammatory response markers (nitric oxide (NO), tumor necrosis factor (TNF-α), myeloperoxidase (MPO), and C-reactive protein (CRP)) were evaluated. The expression profiles of pro-inflammatory cytokines (nuclear factor-kappa B (NF-kB) and interleukin-6 (IL-6)) were also measured by real-time quantitative polymerase chain reaction (qRT-PCR). The results showed that CoCl₂ exposure was associated with significant elevations of oxidative stress and inflammatory indices with reductions in the endogenous tissue antioxidants’ concentrations. Moreover, CoCl₂ enhanced the activity of the NF-κB inflammatory-signaling pathway that plays a role in the associated inflammation of the kidney. MOEE ameliorated CoCl₂-induced renal oxidative damage and inflammatory injury with the suppression of the mRNA expression pattern of pro-inflammatory cytokine-encoding genes. MOEE is more effective when it is administered with CoCl₂ exposure as a prophylactic regimen. In conclusion, MOEE administration exhibited protective effects in counteracting CoCl₂-induced renal injury in rats.

Cobalt accumulation in horses following repeated administration of cobalt chloride

OBJECTIVE

To monitor cobalt concentrations in urine, red blood cells and plasma after chronic parenteral administration of cobalt chloride evaluate these results against the current International Federation of Horseracing Authorities thresholds for detecting cobalt misuse.

DESIGN

Eight mares were randomly assigned to four treatment groups, with two mares in each group: Group 1 - control group, Group 2 - 25 milligrams cobalt intravenously as CoCl₂ weekly, Group 3 - 50 milligrams cobalt intravenously as CoCl₂ weekly, and Group 4 - 25 milligrams cobalt intravenously mid-week and at the end of the week. Urine and blood samples were collected before each weekly administration so that trough levels were assessed. In the group receiving two doses per week, urine and blood were collected prior to the dose given at the end of each week. Samples were initially collected at time zero then weekly for 10 weeks. Three further collections of urine and blood were made at days 81, 106 and 127.

METHODS

Urine creatinine measurements to assess horse hydration status were performed by the Jaffe reaction method. Cobalt determinations in plasma, blood and urine were by inductively coupled plasma-mass spectrometry. Haematocrit concentrations, used to calculate red cell cobalt levels, were performed using a microhematocrit centrifuge. Statistical analyses were conducted in Genstat (v17, VSNi).

RESULTS

Marked cobalt accumulation was evident with increasing cobalt concentrations for all sample matrices in specimens collected immediately prior to cobalt administration. Correlation between the sample matrices improved when urine cobalt concentration was adjusted for creatinine level. Red cell cobalt levels remained elevated for at least 12 weeks after cessation of administration, consistent with the lifespan of the red cell. There was no significant change in haematocrit concentrations for the duration of the study.

CONCLUSION

The current urine cobalt threshold was only effective at detecting acute cobalt exposure while the plasma cobalt threshold was able to consistently identify chronic high-level cobalt exposure and potential cobalt misuse. The threshold values legislated for urine cobalt do not correlate with those set for plasma. The acute nature of urinary cobalt excretion provides a relatively small window through which cobalt administration is detected. Plasma and red cell cobalt concentrations can provide a clearer picture of potential cobalt misuse.

Neuroprotection by luteolin and gallic acid against cobalt chloride-induced behavioural, morphological and neurochemical alterations in Wistar rats

Cobalt (Co) intoxication arising from occupational exposures and ion release from metal implants has been associated with neurological alterations such as cognitive decline, incoordination and depression. The present study evaluated the mechanisms of neuro-protection exerted by Luteolin (Lut; 100 mg/kg) and Gallic acid (GA; 120 mg/kg) in Wistar rats exposed to cobalt chloride (CoCl₂) at 150 mg/kg for 7 consecutive days. Results indicate that CoCl₂ induced neuro-behavioural deficits specifically by decreasing exploratory activities of CoCl₂-exposed rats, increased anxiety, as well as significant reduction in hanging latency. Co-treatment with Lut or GA, however, restored these parameters to values near those of normal controls. Moreover, Lut and GA prevented CoCl₂-induced increases in hydrogen peroxide (H₂O₂), malondialdehyde (MDA) and nitric oxide (NO) in the brain, while also restoring the activities of acetylcholinesterase, glutathione S-transferase (GST) and superoxide dismutase (SOD). In addition, Lut and GA produced significant reversal of CoCl_2-induced elevation in levels of serum Interleukin 1 beta (IL-1β) and Tumor necrosis factor (TNFα). Meanwhile, immunohistochemistry revealed increased astrocytic expression of glial fibrillary acidic protein (GFAP), with intense calbindin (CB) D-28k staining and pronounced dendrites in the Purkinje cells. In contrast, the CoCl₂ group was characterized by decreased number of neurons expressing CB and dendritic loss. Taken together, mechanisms of luteolin and/or gallic acid protection against Co toxicity involved restoration of Ca²⁺ homeostasis, acetylcholinesterase and antioxidant enzyme activities, as well as inhibition of lipid peroxidation in the brain.

Selective Contribution of Bioactive Glasses to Molecular and Cellular Pathways

Over the past few decades, biomedical scientists and surgeons have given substantial attention to bioactive glasses as promising, long-lasting biomaterials that can make chemical connections with the neighboring hard and soft tissues. Several studies have examined the cellular and molecular responses to bioactive glasses to determine if they are suitable biomaterials for tissue engineering and regenerative medicine. In this regard, different ions and additives have been used recently to induce specific characteristics for selective cellular and molecular responses. This Review briefly describes foreign-body response mechanisms and the role of adsorbed proteins as the key players in starting interactions between cells and biomaterials. It then explains the physicochemical properties of the most common bioactive glasses, which have a significant impact on their cellular and molecular responses. It is expected that, with the development of novel strategies, the physiochemical properties of bioactive glasses can be engineered to precisely control proteins' adsorption and cellular functions after implantation.

Cardiac Pathology and Genomics of Sudden Death in Racehorses From New York and Maryland Racetracks

Postmortem evaluation of racehorses has focused primarily on musculoskeletal injuries; however, horses also die suddenly on the track (sudden death [SD]). Although cardiac conditions are frequently suspected as a cause of death, SD racehorses are often autopsy negative; however, previous studies have been limited due to inconsistent or insufficient cardiac sampling and lack of controls. SD in New York (NY) and Maryland (MD) racehorses was evaluated in an observational case vs control study comparing clinical information, postmortem evaluation including cardiac dissection, and cardiac conduction system histopathology. In the study period, there were 40 cases of SD. In NY, SD occurred in 12% (37/316) of submissions, and 36 (11%) cases of SD were exercise associated (EASD); 3 EASD cases occurred in MD. In NY/MD EASD cases with histologic examination of the heart, 11 of 36 (31%) had significant lesions, including mesenteric artery rupture (1), axial trauma (2), systemic inflammation (2), pulmonary hemorrhage (1), and cardiac disease (5). Mild myocardial fibrosis, mild inflammation, coronary arteriosclerosis, and variation in cardiac nodal connective tissue were present in both SD cases and controls and thus were not considered to be causes of SD. While not excluding a genetic basis for SD, analysis of the genotypes (GGP Equine 70 K Array) of cases and controls did not reveal significant differences in allele frequencies at any locus. Most SD racehorses were autopsy negative; further research using standardized protocols and controls is needed to understand the underlying causes of SD, which is crucial to protecting the viability of racing.

Effect of Intravenous Administration of Cobalt Chloride to Horses on Clinical and Hemodynamic Variables

Background

Cobalt chloride (CoCl₂) is administered to racehorses to enhance performance. The purpose of this study was to evaluate the clinical, cardiovascular, and endocrine effects of parenterally administered CoCl₂.

Objectives

To describe the effects of weekly intravenous doses of CoCl₂ on Standardbred horses.

Animals

Five, healthy Standardbred mares.

Methods

Prospective, randomized, experimental dose‐escalation pilot. Five Standardbred mares were assigned to receive 1 of 5 doses of CoCl₂ (4, 2, 1, 0.5, or 0.25 mg/kg) weekly IV for 5 weeks. Physical examination, blood pressure, cardiac output, and electrocardiography (ECG) were evaluated for 4 hours after administration of the first and fifth doses. Blood and urine samples were collected for evaluation of cobalt concentration, CBC and clinical chemistry, and hormone concentrations.

Results

All mares displayed pawing, nostril flaring, muscle tremors, and straining after CoCl₂ infusion. Mares receiving 4, 2, or 1 mg/kg doses developed tachycardia after dosing (HR 60–126 bpm). Ventricular tachycardia was noted for 10 minutes after administration of the 4 mg/kg dose. Increases in systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) occurred after administration of all doses (4, 2, 1, 0.5, and 0.25 mg/kg). Profound hypertension was observed after the 4 mg/kg dose (SAP/DAP, MAP [mmHg] = 291–300/163–213, 218–279). Hemodynamics normalized by 1–2 hours after administration. ACTH and cortisol concentrations increased within 30 minutes of administration of all CoCl₂ doses, and cardiac troponin I concentration increased after administration of the 4 and 2 mg/kg doses.

Conclusions and Clinical Importance

The degree of hypertension and arrhythmia observed after IV CoCl₂ administration raises animal welfare and human safety concerns.

Cobalt chloride exposure dose-dependently induced hepatotoxicity through enhancement of cyclooxygenase-2 (COX-2)/B-cell associated protein X (BAX) signaling and genotoxicity in Wistar rats

Cobalt chloride (CoCl₂ ) is one of the many environmental contaminants, used in numerous industrial sectors. It is a pollutant with deadly toxicological consequences both in developing and developed countries. We investigated toxicological impact of CoCl₂ on hepatic antioxidant status, apoptosis, and genotoxicity. Forty Wistar rats were divided into four groups, 10 rats per group: Group 1 served as control and received clean tap water orally; Group 2 received CoCl₂ solution (150 mg/L); Group 3 received CoCl₂ solution (300 mg/L); and Group 4 received CoCl₂ (600 mg/L) in drinking water for 7 days, respectively. Exposure of rats to CoCl₂ led to a significant decline in hepatic antioxidant enzymes together with significant increase in markers of oxidative stress. Immunohistochemistry revealed dose-dependent increase in cyclooxygenase-2 and BAX expressions together with increased frequency of Micronucleated Polychromatic Erythrocytes. Combining all, CoCl₂ administration led to hepatic damage through induction of oxidative stress, inflammation, and apoptosis.

Protective effects of kolaviron and gallic acid against cobalt-chloride-induced cardiorenal dysfunction via suppression of oxidative stress and activation of the ERK signaling pathway

Cobalt (Co) toxicity is a potential public health problem due to recent renewed use of Co in orthopedic implants, dietary supplements, and blood doping in athletes and horses. We investigated the protective roles of kolaviron (KV), a bi-flavonoid of Garcinia kola, and gallic acid (GA) on cobalt chloride (CoCl2)-induced cardiorenal damage in rats. CoCl2 caused significant increases (p < 0.05) in serum creatine kinase–myocardial band (CK-MB), lactate dehydrogenase (LDH), aspartate transaminase (AST), xanthine oxidase (XO), urea, creatinine, malondialdehyde, H2O2, nitric oxide, as well as C-reactive protein expression, along with significant (p < 0.05) reduction in cardiac and renal expression of extracellular signal regulated kinase (ERK) and the activities of superoxide dismutase, catalase, and glutathione S-transferase. KV and GA prevented the toxic effects of CoCl2 by stimulating ERK expression and reversing Co-induced biochemical changes. Administration of CoCl2 alone did not significantly alter ECG patterns in the rats, although co-treatment with KV (200 mg/kg) produced QT-segment prolongation and also appeared to potentiate Co hypotension. Histopathology of the heart and kidneys of rats treated with KV and GA confirmed the biochemical data. KV and GA thus protected against cardiac and renal damage in Co intoxication via antioxidant and (or) cell survival mechanisms, possibly involving ERK activation.