Evaluation of Plasmid Delivery by Electroporation as a Means of Increasing Gonadotropin-Releasing Hormone Production in Stallions

Document Type

Article

Publication Date

3-1-2008

Abstract

A plasmid delivery system validated in other species was assessed for its potential for inducing long-term expression of gonadotropin-releasing hormone (GnRH) in stallions. The efficacy of this technique was demonstrated using two plasmids: pSEAP, expressing secreted embryonic alkaline phosphatase (SEAP), and pGnRH, expressing GnRH. In experiment 1, geldings were used as a model to test the effect of muscle of injection (splenius, pectoralis, and semitendinosus; n = 3 for each site) on the expression of the reporter plasmid, pSEAP. Concentrations of SEAP rose (P < .01) in jugular plasma samples, indicating uptake and expression of the pSEAP plasmid. Concentrations of SEAP were greatest (P < .05) and most consistent after pectoralis injection, and this site was chosen for injection and electroporation in the subsequent experiment. In ex-periment 2, stallions were treated with pGnRH (2 mg, n = 3; and 4 mg, n = 3) or 2 mg of pSEAP (control; n = 4) to determine the effects on the reproductive axis. Treatment with pGnRH (day 0) resulted in higher (P < .05) plasma testosterone concentrations from day 35 to 56 and increased the luteinizing hormone (LH) (P < 0.01) and testosterone (P < .1) responses to GnRH challenge on day 21. Daily semen characteristics from days 31 to 36 showed no effect (P > .1) of pGnRH treatment on seminal characteristics. It was concluded that delivery by electroporation of plasmids encoding peptide hormones may serve as a means of long-term in vivo production of peptides in the horse. Increases in LH and testosterone secretion after GnRH were observed in pGnRH-treated stallions; however, optimal conditions for expression need to be determined in future experiments. © 2008 Elsevier Inc. All rights reserved.

Publication Source (Journal or Book title)

Journal of Equine Veterinary Science

First Page

149

Last Page

155

This document is currently not available here.

Share

COinS