Emmanuel Fontaine

Clinical use of GnRH agonists in canine and feline species.

GnRH (gonadotrophin releasing hormone) is a key hormone of reproductive function in mammals; agonist forms have been largely developed, and data concerning their use in small animal reproduction are now abundant. GnRH agonists act by a two-step mechanism. First, their agonist properties on the pituitary will cause marked LH (luteinizing hormone) and FSH (follicle-stimulating hormone) secretion into the bloodstream, accompanied by an increase in the concentrations of sex steroid hormones. Then, in case of constant administration, GnRH agonists will lead to pituitary desensitization, and FSH and LH levels will collapse. These two effects have been widely documented, and these compounds have many potential benefits in a clinical context, capitalizing both on their stimulating and sterilizing effects.

Findings in uterine biopsies obtained by laparotomy from bitches with unexplained infertility or pregnancy loss: An observational study

Surgical uterine biopsies (SUBs) were obtained by laparotomy from 14 bitches with unexplained infertility whose pregnancy was not confirmed (NCP group) and from 7 bitches that had experienced unexplained pregnancy loss (PL). SUBs were obtained during the luteal phase of the cycle in 16 of 21 bitches. Overall, the biopsied uterine tissues presented obvious alterations in 17 of 21 cases. In the NCP group, 11 of 14 bitches had varying degrees of uterine lesions. In this group, six of nine bitches with macroscopically normal uteri presented histopathologic changes in the endometrium. All bitches with macroscopic modifications (five of 14) presented endometrial changes. Cytologic examination of the uterine fluid revealed eosinophilic amorphous material, erythrocytes, and a low number of degenerated leukocytes. On histopathologic examination, the most common lesion was fibrosis with degeneration of the endometrial glands (FDEGs six of 11), followed by endometritis (four of 11), cystic endometrial hyperplasia (CEH) (two of 11) and pseudoplacentational endometrial hyperplasia (PEH) (two of 11). Other lesions were adenomyosis, mucometra, and an endometrial polyp (one each of 11). Mixed lesions were present in four of the 11 bitches. In the PL group, macroscopic modifications consisted of intraluminal uterine dilatation (seven of seven) and presence of ovarian cysts (three of 7). Cytologic examination of the uterine content revealed high leukocyte counts. Histopathologic endometrial changes were found in six of seven bitches and included endometritis (three of seven), PEH (two of 6), pyometra (one of six), and CEH together with mucometra (one of six). Research of infectious agents was performed in 20 of 21 cases. Surprisingly, no bacteria or viruses were isolated from the uterine lumen in any of the cases. When the SUB was performed in diestrus, a medical treatment with aglepristone or with prostaglandins was established to avoid the risk of postoperative-induced pyometra. One case of complete uterine stenosis was the only side effect observed in the bitches that were not ovariohysterectomized after the collection of a biopsy (17 of 21). In conclusion, the most common findings in our biopsy specimens were FDEGs, endometritis, and hyperplastic remodeling of the endometrium (CEH and PEH). SUBs might provide useful information regarding the cause of infertility or PL. This technique allows visual inspection and palpation of the whole uterus and ovaries before the selection of a precise site for the biopsy. The size of the tissue sample collected can be large enough for an accurate diagnosis and samples for research of infectious agents can be obtained with no risk of contamination. Risk of side effects seems low when SUBs are performed according to this protocol, including postsurgery treatment with aglepristone or prostaglandins.

Elective Caesarean Operation in the Bitch Using Aglepristone Before the Pre-Partum Decline in Peripheral Progesterone Concentration

The aim of this study was to investigate caesarean operation (CO) undertaken before the pre-partum decrease of progesterone but following administration of a progesterone receptor antagonist and to evaluate the innocuity of this procedure for the dam and pups. Thirty seven bitches of 15 different breeds, received an injection of 15 mg/kg aglepristone 59 or 60 days after the estimated day of ovulation, determined by progesterone quantitative assays, and caesarean section (CS) was performed between 20 and 24 h after administration. Progesterone remained above 6 nmol/l at the time of CS (mean = 15.75, SD = 3.84). No post-operative clinical complications were reported in any of the bitches. All bitches were able to nurse and feed their puppies in the first 24 h following surgery. No pups showed any signs of prematurity and 5 out of 188 pups (2.6) died in the first 2 weeks after delivery. This small study demonstrates that a CS may be safely and successfully performed an average of 2 days before the expected date of parturition following the administration of aglepristone, without any harmful consequence for the dam and her neonates.

L'insémination artificielle chez les félidés

Linsemination artificielle chez le chat domestique et les felides sauvages repond a plusieurs indications. Chez le chat, elle peut notamment permettre daider la reproduction lorsque laccouplement ne se produit pas ou difficilement et de favoriser les echanges geographiques de semence et donc un brassage et une meilleure selection genetiques. Chez les felins sauvages, elle joue un role complementaire au sein des programmes de conservation. Son utilisation est cependant complexe. Loestrus et lovulation sont le plus souvent induits par lemploi de gonadotropines qui possedent cependant des effets indesirables, notamment un risque dhyperstimulation ovarienne. La semence des mâles est generalement recoltee par electro-ejaculation. Elle peut etre congelee. Neanmoins, un probleme specifique aux felins tient a la teratospermie, cest-a-dire la production de nombreux spermatozoides porteurs danomalies morphologiques. Linsemination artificielle donne de meilleurs resultats lorsque la semence est deposee par voie intra-uterine. Pendant longtemps, la laparoscopie a ete la technique de reference, mais recemment, des techniques de catheterisme du col uterin par voie vaginale ont ete mises au point, aussi bien chez le chat que chez certains felides sauvages. Les resultats de linsemination artificielle chez les felides restent moyens (souvent moins de 50 % de gestations obtenues).

Fertility in Adult Bitches Previously Treated with a 4.7 mg Subcutaneous Deslorelin Implant

The absence of fertility problems in male dogs after a single treatment with deslorelin acetate (Suprelorin(®)) is well acknowledged. However, reports on the application of deslorelin in the bitch and information concerning fertility after implant treatment are still limited. In this retrospective study, data concerning induced and spontaneous oestruses of 39 bitches from 17 breeds, treated with deslorelin acetate implants (4.7 mg Suprelorin(®), Virbac, France), were retrieved to assess post-treatment fertility (ovulation rate, pregnancy rate and litter size). Animals were grouped according to treatment characteristics: group 1 (Gr1) - females submitted to oestrus induction, showing natural oestruses afterwards (n = 19); group 2 (Gr2) - females re-implanted with 4.7 mg deslorelin acetate to re-induce oestrus, showing subsequent spontaneous post-implant oestruses (n = 7); and group 3 (Gr3) - females submitted to a 4.7 mg deslorelin acetate implant for oestrus suppression, evaluated at subsequent spontaneous post-implant oestruses (n = 13). Comparison of fertility traits between induced and post-treatment spontaneous oestruses in Gr1 and Gr2 (short treatments), or between spontaneous oestruses after long-treatment schedules (Gr 3) revealed a slightly better performance in spontaneous cycles compared with induced cycles: ovulation rate post-treatment was 97.1%, 94.1% and 94.4% and the pregnancy rate post-treatment was 91.2%, 88.9% and 84.6% for groups 1, 2 and 3, respectively. Nevertheless, fertility in induced and post-treatment oestruses was considered normal. Moreover, the individual litter size did not differ within groups between induced and spontaneous cycles. From these findings, we concluded that treatment with 4.7 mg deslorelin implants did not compromise the bitches fertility in subsequent oestruses.

UTILISATION D’IMPLANTS SOUS-CUTANÉS D’AGONISTES DE LA GNRH CHEZ LES CARNIVORES DOMESTIQUES POUR MAÎTRISER LA REPRODUCTION

The recent commercialisation in Europe of sub-cutaneous implants containing an agonist of the hypothalamic n hormone GnRH, called deslorelin, has been done in the purpose of offering a chemical alternative n to surgical castration in the adult male dog. The efficacy of these implants in this indication n is real. They have an action on the endocrine function ( spectacular diminution of testosteronemia), n on the exocrine function (alteration of sperm quality and infertility) and on the clinical evolution ( n diminution of the size of the testis). The availability of these implants also gave rise to numerous other n indications in the canine and feline species. Many recent publications, or even unpublished studies n still going on, seem to show an interest in the improvement of unpleasant behavior potentially linked n with testosterone in the male, but also to prevent fertility in the adult male cat and to prevent oestrus n in the bitch or in the queen. Implantation of pre-pubertal animals to postpone puberty seems successful. n In the adult bitch, induction of a fertile oestrus post-implantation is even possible, which bears n a zootechnical interest. However, secondary effects, duration of action and further fertility after implantation n are not well known at the moment and need to be further studied

Utilisation du laboratoire en gynécologie et andrologie canines

Resume En gynecologie et andrologie veterinaire, le laboratoire joue un role cle entre la clinique et les examens paracliniques complementaires plus pousses. Le role central du microscope est indeniable : determination du stade du cycle chez la femelle, analyse de semence chez le mâle, detection d’affections de l’appareil genital,… autant d’indications qui font qu’il serait impossible de s’en priver. L’utilisation de cet outil s’accompagne neanmoins aujourd’hui de celle d’analyseurs (principalement pour les dosages hormonaux) et de systemes automatises (evaluation de la semence, morphometrie) qui permettent d’augmenter la precision des mesures effectuees et par la meme occasion, facilitent la gestion d’une activite qui n’a de cesse de se developper.

MICROENVIRONNEMENT TUBAIRE: RÔLE DANS LA MATURATION DES OVOCYTES CANINS IN VIVO ET IN VITRO

Chez la plupart des mammiferes, les ovocytes sont bloques en metaphase II au moment de lovulation et cette inhibition de la meiose est ensuite levee par la fecondation. Chez les chiennes et les autres femelles de canides, les ovocytes sont liberes au stade de prophase I, et il faut encore attendre 48 a 72 heures pour quils atteignent le stade de metaphase II et deviennent fecondables. Cette particularite constitue aujourdhui un frein au developpement des biotechnologies de la reproduction chez les canides. En effet, dans les essais de maturation in vitro dovocytes canins, seuls 10 a 30 % des ovocytes atteignent le stade de metaphase au bout de 72 heures de culture. Chez la chienne, la maturation nucleaire se produisant dans loviducte, des substituts de loviducte (milieux de culture comme le Synthetic Oviductal Fluid, explants doviductes, cultures sur tapis de cellules tubaires) ont ete utilises pour les cultures dovocytes in vitro, afin den ameliorer le rendement, mais sans grand succes jusqua maintenant. Cet echec peut etre du au manque de donnees sur la composition du liquide tubaire de la chienne. Letude de ce microenvironnement prend donc tout son interet, celui-ci etant probablement assez different de celui des autres femelles, ne serait-ce que par lexistence du processus de luteinisation preovulatoire dans cette espece. A terme, la conception dun milieu de maturation sur la base de la composition du liquide tubaire pourrait etre une voie interessante pour augmenter les taux de maturation in vitro.