Effect of Mycobacterium cell wall fraction on endometrial histomorphometry of mares resistant and susceptible to persistent breeding-induced endometritis

HERRERA MARCELA F.; OTERMIN MARTINA ; HERRERA JUAN MANUEL; SIMOY MARÍA VERÓNICA; BIANCHI CAROLINA P.; AGUILAR JAVIER; FUMOSO ELIDA

THERIOGENOLOGY

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2020

0093-691X

Mycobacterium cell wall fraction (MCWF) is a biological component made up of molecules with immunostimulant properties, which is therapeutically used to reverse persistent breeding-induced endometritis (PBIE). The aim of this study was to analyze the effect of an immunomodulator on the endometrial histological structure during the diestrus of PBIE-resistant and -susceptible mares that were treated or untreated with MCWF. The experiment was conducted with 10 resistant mares (RM) and 9 susceptible mares (SM). In the first estrous cycle of the trial, all mares were inseminated with dead semen as an inflammatory stimulus, and they constituted Group A; at the next cycle, all mares were inseminated with dead semen and treated with a MCWF commercial immunomodulator, constituting Group B. In both groups, endometrial biopsies were taken on day 7 post-ovulation (diestrus). Endometrial biopsies of untreated-RM (UTRM, n=6), untreated-SM (UTSM, n=7,) MCWF-treated-RM (TRM, n=6) and MCWF-treated-SM (TSM, n=6) were evaluated. They were randomly chosen as representative mares of Group A and B, respectively. The height of lining and glandular epithelia, glandular diameter, glandular density and glandular area were evaluated. The histological structure revealed lymphocytic infiltration and dilated, tortuous glands with some glandular nests, particularly in UTSM. The histomorphometrical results show no differences (ρ> 0.05) between the analyzed groups. This would indicate that post-service treatment with the MCWF immunomodulator does not modify the endometrial histoarchitecture but, apparently, its action would be mainly based on the stimulation of the cellular and humoral immune responses.