A Critical Review on the Pharmacodynamics and Pharmacokinetics of Non-steroidal Anti-inflammatory Drugs and Opioid Drugs Used in Reptiles

Pain Management for Gastrointestinal Conditions in Exotic Animals

Gastrointestinal (GI) disorders are very common in exotic animals, such as reptiles, birds, mammals, and can be extremely painful. This review aims to provide the reader with a better understanding of the different pain mechanisms and manifestations across orders and species in order to provide the most updated information on pain recognition and management for GI conditions in exotic animals.

Mesenchymal stromal cell isolation from pond slider (Trachemys scripta) adipose tissue obtained during routine neutering: a model for turtle species

Introduction

Mesenchymal stromal cells (MSCs) hold great clinical potential in veterinary regenerative medicine. However, a notable gap exists in the literature regarding the isolation and characterization of these cells in reptiles. The objective of this study was to evaluate the feasibility of isolating adipose tissue-derived mesenchymal stem cells (MSCs) from pond slider (Trachemys scripta) tissue samples collected during routine neutering procedures.

Methods

Adipose tissue samples were obtained from five animals and processed using an enzymatic procedure. The resulting cell suspension was subsequently cultured at 28°C in a controlled atmosphere with 5% CO2. The cell growth rates were evaluated through direct counting of cells up to passage 7. The colony-forming unit (CFU) capacity of MSCs was evaluated in low-density cell cultures, and the ability of the cells to differentiate into adipogenic, chondrogenic and osteogenic lineages was assessed. The cell phenotype was characterized at the molecular level using reverse transcription-polymerase chain reaction (RT-PCR) and amplicon sequencing, with a focus on markers commonly used for gene expression profiling of mammalian MSCs.

Results

The cells demonstrated the capacity to differentiate into adipogenic, chondrogenic, and osteogenic lineages. RT-PCR revealed the expression of CD105, CD73, CD44, and CD90, whereas CD34 and HLA-DRA were not expressed. Sequence homology analysis demonstrated that the amplicons matched the sequences reported in the Trachemys scripta whole-genome shotgun sequence. This study represents the first investigation aimed at the isolation, in vitro expansion, and characterization of reptile adipose tissue-derived MSCs.

Discussion

The results demonstrate the feasibility of isolating MSC-like cells from chelonian adipose tissue and underscore their potential for application in regenerative medicine for both companion reptiles and endangered wild species.

Effectiveness, Safety, and Pharmacokinetics of Meloxicam Formulations in African-clawed Frogs, Xenopus laevis

Pain management in amphibians is an emerging field of veterinary medicine with only a limited number of analgesics studied for their efficacy. The African-clawed frog, Xenopus laevis, is a popular animal model in research due to its oocyte morphology and embryonic development. We investigated analgesic effects of 2 formulations of meloxicam (standard and extended release [ER]) along with their pharmacokinetics and potential toxicity in this species. Adult female African-clawed frogs (n = 6/group) received either standard (0.2, 0.4, 1, or 5 mg/kg) or ER meloxicam (0.6, 1.2, 3, or 15 mg/kg) injected into the dorsal lymph sac. The acetic acid test (AAT) was performed at -1, 1, 6, 12, 24, 48, and 72 h postadministration to evaluate pain response. In addition, a subset of frogs (n = 2/group) were euthanized 72 h postinjection and submitted for necropsy. There were no significant differences in AAT with both formulations compared with saline control. No signs of meloxicam-induced toxicity with either formulation was present in histology. A pharmacokinetic study was conducted for both the standard and ER formulation of meloxicam at 5 and 15 mg/kg, respectively. Results were consistent with the fact that both formulations of meloxicam were readily absorbed with the standard plasma concentrations peaking at 20.40 µg/mL at 2 h and ER plasma concentration at 30.4 µg/mL at 12 h. The elimination half-life was only determinable for standard formulation (7.74 h). According to the AAT, both formulations of meloxicam did not provide effective analgesia in adult female Xenopus laevis despite reaching high plasma concentrations.

PHARMACOKINETICS OF SINGLE INTRAMUSCULAR ADMINISTRATION OF CEFTIOFUR CRYSTALLINE FREE ACID IN AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS)

A pharmacokinetic study of ceftiofur crystalline free acid sterile oil suspension (CCFA) was performed in six apparently healthy juvenile American alligators (Alligator mississippiensis). A single intramuscular dose of 30 mg/kg was administered in the triceps muscle. Blood samples were collected prior to treatment and at 4, 12, 24, 48, 72, 120, 144, 192, 288, and 366 h post administration. Plasma samples were analyzed for ceftiofur equivalent concentrations using liquid chromatography-mass spectrometry. Pharmacokinetic parameters were determined by noncompartmental analysis. Mean peak plasma concentration was 23.2 µg/ml (range, 16.0-27.9), median time to maximum concentration was 72 h (range, 72-120), mean area under the curve from 0 to 366 h postdose was 4.24 h · mg/ml (range, 3.54-4.97), and mean terminal half-life was 143 h (range, 90.8-220). Plasma concentrations were maintained above the minimum inhibitory concentration for this study of 2.0 µg/ml, which was established from similar CCFA pharmacokinetic studies in other reptilian species, through the end of the data collection of 366 h. Because of prolonged plasma concentrations, a dosing interval could not be established in this study. Future studies should include extended collection time points and multidose studies to determine dosing regimens.

Egg Removal via Cloacoscopy in Three Dystocic Leopard Geckos (Eublepharis macularius)

Dystocia is a multifactorial, life-threatening condition commonly affecting pet reptiles. Treatment for dystocia can be either medical or surgical. Medical treatment usually involves the administration of oxytocin, but in some species or, in some cases, this treatment does not work as expected. Surgical treatments such as ovariectomy or ovariosalpingectomy are resolutive, but invasive in small-sized reptiles. In this paper, we describe three cases of post ovulatory egg retention in three leopard geckos (Eublepharis macularius) successfully treated through a cloacoscopic removal of the retained eggs, after a non resolutive medical treatment. The intervention was fast, non-invasive, and no procedure-related adverse effects were noted. The problem relapsed six months later in one animal, and a successful bilateral ovariosalpingectomy was performed. Cloacoscopy should be considered a valuable, non-invasive tool for egg removal in dystocic leopard geckos when the egg is accessible to manipulation. Recrudescence or complications such as adhesions, oviductal rupture, or the presence of ectopic eggs should recommend surgical intervention.