Theses and Dissertations

ORCID

0009-0002-4537-0438

Issuing Body

Mississippi State University

Advisor

Archer, Todd M.

Committee Member

Howell, George Eli, III

Committee Member

Correa Natalini, Claudio

Committee Member

Mackin, Andrew J.

Committee Member

Meyer, Robert E.

Date of Degree

8-8-2023

Document Type

Dissertation - Campus Access Only

Major

Veterinary Medicine

Degree Name

Doctor of Philosophy (Ph.D)

College

College of Veterinary Medicine

Department

Department of Clinical Sciences

Abstract

In the 19th century, halothane hepatitis became a sensitive and well-known subject in human anesthesiology due to the production of a noxious metabolite further discovered, trifluoroacetic acid. Subsequently, isoflurane, enflurane, and desflurane were also investigated for potentially causing hepatitis through the same metabolite. Sevoflurane, however, does not generate trifluoroacetic acid and is quickly conjugated and excreted.

For more than four decades these anesthetics have been experimentally developed for intravenous injection by having added either a lipid or fluorocarbon-based carrier to produce general anesthesia with less drug and faster onset of action. The use of intravenous emulsified halogenated anesthetics as an alternative to inhalation brought contradictory findings, therefore they are still not utilized in the clinical settings of veterinary and human anesthesia.

The high solubility of these anesthetic emulsions increases their tissue uptake, volume of distribution, and potency. By this means, the amount of anesthetic necessary to establish general anesthesia could be significantly reduced but would still carry the risk of causing hepatic toxicity. On the other hand, because the emulsified anesthetics have a higher tissue uptake and are liposoluble, they remain for longer periods in the cellular membrane providing cellular pre- and postconditioning effects by minimizing cellular deleterious responses to a critical environment. Emulsified isoflurane and sevoflurane are the most investigated anesthetics for this purposein the heart, brain, kidneys, liver, and central nervous system of laboratory animals and human volunteers.

The focus of this study is to evaluate the cellular effects of the loaded-lipid emulsified isoflurane and sevoflurane at different concentrations on cultured primary canine hepatocytes considering their viability and apoptosis response. Specifically, the overall objective is to establish a basis for in vitro metabolism of these emulsified anesthetics on canine hepatocytes under normal oxygen tension and on canine hepatocytes exposed to extreme hypoxia (1% O2). Thus, this study is sectioned into three major chapters followed by conclusions and future studies to determine the safety and indication of these anesthetic formulations in canine hepatocytes to be further explored in the clinical setting with live animals.

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