The Influence of a Single Acetic Acid and LacticAcid Injection on Rat Normal Thyroid Tissue

Overview

Until now, the use of acetic and lactic acid for the treatment of thyroid nodular lesions, as well ashistopathologic changes in the thyroid tissue after their intrathyroidal injections has not beendescribed. The aim of this study is to evaluate macro- and microscopic changes in rat normalthyroid tissue induced by single intrathyroidal injection of acetic acid (AA) and lactic acid (LA) indifferent concentrations, as well as the influence of intrathyroidal acid injection on function ofthe recurrent laryngeal nerves.Male Wistar rats were divided into two groups of 50 (Group A and B). Rats of each group weredivided into the subgroups of five. In each subgroup of Group A and B, AA and LA water solutionsof different concentrations (0%, 2.5%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 80%), respectively, wereinjected into the right thyroid lobe.From Group A and B, 7 and 8 rats died, respectively (after injections of 50-80% AA and LA solutions).After 4 weeks post AA or LA injection the thyroid along with the surrounding tissues was excisedand assessed macro- and microscopically in all rats that survived. Before the injection and justbefore the second operation, the vocal cord function was evaluated.Our results show that both, acetic and lactic acid of different concentrations damage rat normalthyroid tissue after a single intrathyroidal injection. The minimal concentrations of acetic andlactic acid that cause lethal changes in rat normal thyroid tissue are 20% and 10%, respectively.Acetic and lactic acid in the concentrations of 40% and 50%, respectively, and higher can causeinjury of the tissues adjacent to the thyroid.

Key words:
acetic acid - lactic acid - thyroid nodule - percutaneous injection