Dimethyl sulfoxide intrauterine therapy in the mare: Effect upon uterine-derived neutrophil function

Abstract

Twelve mares were evaluated reproductively and divided into two groups (n = 6 each) according to their status as either resistant or susceptible to chronic uterine infections. Each mare per group was challenged by intrauterine bacterial culture ultrafiltrate infusion to stimulate uterine cellular defense mechanisms. Two hours post innoculum challenge, mares received either sham, sterile saline or 18g DMSO (30% solution) intrauterine infusion treatment. Fourteen hours post innoculum challenge uterine lavage was performed on each mare to recover uterine polymorphonuclear (PMN) leukocytes. The uterine-derived PMNs were then studied in vitro for functional characteristics that included basal intracellular free calcium content, intracellular calcium release response rates, respiratory burst activity, superoxide production, lysosomal enzyme production and phagocytosis response. Analysis of these parameters, comparing uterine-derived PMN functions betweeen the two groups (resistant vs susceptible mares) were no different (P>0.05), with the exception of a significant difference (P = 0.0244) for basal intracellular free calcium content, which was lower in the susceptible group of mares. The effects of the intrauterine treatments administered upon the cellular functions of the uterine-derived PMNs revealed no differences (P > 0.05) between mare groups. Animal by group and treatment by group interactions were not detected using a general linear models procedure (P > 0.05). By these methods, the uterine-derived PMN functions were no different between mares classified as resistant to chronic uterine infections vs those classified as susceptible to chronic uterine infections. The administration of 30% DMSO as an intrauterine infusion (18g DMSO/mare) produced effects upon uterine-derived PMN function parameters studied here that were no different (P > 0.05) than either sham or saline intrauterine treatments.