Validation of the IDS Octeia ELISA for the determination of insulin-like growth factor 1 in equine serum and tendon tissue extracts

Authors

  • Tone Lygren,

    1. Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark
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  • Peter Schjerling,

    1. Institute of Sports Medicine, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Copenhagen NV, Denmark
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  • Stine Jacobsen,

    1. Department of Production Animals and Horses, Faculty of Life Sciences, University of Copenhagen, Taastrup, Denmark
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  • Lise C. Berg,

    1. Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark
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  • Mette O. Nielsen,

    1. Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark
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  • Henning Langberg,

    1. Institute of Sports Medicine, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Copenhagen NV, Denmark
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  • Preben D. Thomsen

    Corresponding author
    • Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark
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Correspondence

Preben Dybdahl Thomsen, Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Groennegaardsvej 7, Frederiksberg DK-1870, Denmark

E-mail: pdt@sund.ku.dk

Abstract

Background

Insulin-like growth factor (IGF-1) is an important mediator of tissue repair in horses.

Objectives

The aim of the study was to evaluate whether IGF-1 could be measured reliably in equine serum and tendon tissue extracts, using an IGF-1 ELISA kit developed for human serum and plasma.

Methods

A glycyl-glycine pretreatment protocol of samples was compared with the pretreatment procedure recommended by the manufacturer. Intra- and inter-assay imprecision were evaluated by repeated measurements of equine serum pools. Assay inaccuracy was determined based on the linearity of serially diluted equine serum samples and tendon tissue extracts. The recovery of IGF-1 was evaluated in serum and tendon tissue extracts spiked with known amounts of IGF-1.

Results

The range of IGF-1 released using the manufacturer's pretreatment was between 23% and 56% of the amount released using the gly-gly pretreatment in different equine samples. In serum pools with low, intermediate, and high IGF-1 concentrations, intra-assay imprecision was 4.0%, 4.0%, and 3.1%, respectively, and inter-assay imprecision was 13.9%, 7.3%, and 12.8%, respectively. The recovery of serially diluted serum was 96 ± 3% when diluted with serum, and 72 ± 15% when diluted with PBS. The recovery after dilution was 108 ± 17% in tendon tissue extracts. Recovery from serum spiked with a fixed amount of IGF-1 was 101 ± 5% and 99 ± 7% from tendon tissue samples.

Conclusions

The IDS Octeia IGF-1 ELISA kit can be used for measuring IGF-1 in equine serum and tendon tissue extract after pretreatment with glycyl-glycine.

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