Anti-Müllerian hormone concentrations in female rabbits and its relation to spay status, pseudopregnancy and ovarian follicle numbers

Endocrine Diagnostics: Principles and Applications

Endocrine diagnostics currently depend on the ability to measure low and high concentrations of diagnostic hormones using immunoassays. This often is challenging in species other than humans, dogs, cats, and horses due to lack of validated assays and reference intervals. There are strategies to approach endocrine testing in zoo, wildlife, and zoologic companion animals but caution is needed in interpreting results. Newer techniques such as liquid chromatography-tandem mass spectrometry (LC-MS/MS) may be more useful for all species, although technical hurdles remain for this method too.

Adrenal Disease in Small Mammals

Adrenal gland disease has been described as a rare disease in pet rabbits and rodents. Hyperadrenocorticism with excessive secretion of corticosteroids is most commonly observed in guinea pigs and hamsters, with dermatologic signs similar to those seen in dogs. Diagnosis is based on clinical signs, diagnostic imaging such as abdominal ultrasound, and determination of the blood hormone concentrations. In guinea pigs, an adrenocorticotrophic hormone stimulation test with the measurement of salivary cortisol or corticosterone concentrations is recommended. The recommended treatment of adrenal disease in guinea pigs and hamsters is oral administration of trilostane or ketoconazole; surgical treatment is also possible.

Folliculogenesis and steroidogenesis alterations after chronic exposure to a human-relevant mixture of environmental toxicants spare the ovarian reserve in the rabbit model

BACKGROUND

Industrial progress has led to the omnipresence of chemicals in the environment of the general population, including reproductive-aged and pregnant women. The reproductive function of females is a well-known target of endocrine-disrupting chemicals. This function holds biological processes that are decisive for the fertility of women themselves and for the health of future generations. However, insufficient research has evaluated the risk of combined mixtures on this function. This study aimed to assess the direct impacts of a realistic exposure to eight combined environmental toxicants on the critical process of folliculogenesis.

METHODS

Female rabbits were exposed daily and orally to either a mixture of eight environmental toxicants (F group) or the solvent mixture (NE group, control) from 2 to 19 weeks of age. The doses were computed from previous toxicokinetic data to reproduce steady-state serum concentrations in rabbits in the range of those encountered in pregnant women. Ovarian function was evaluated through macroscopic and histological analysis of the ovaries, serum hormonal assays and analysis of the expression of steroidogenic enzymes. Cellular dynamics in the ovary were further investigated with Ki67 staining and TUNEL assays.

RESULTS

F rabbits grew similarly as NE rabbits but exhibited higher total and high-density lipoprotein (HDL) cholesterol levels in adulthood. They also presented a significantly elevated serum testosterone concentrations, while estradiol, progesterone, AMH and DHEA levels remained unaffected. The measurement of gonadotropins, androstenedione, pregnenolone and estrone levels yielded values below the limit of quantification. Among the 7 steroidogenic enzymes tested, an isolated higher expression of Cyp19a1 was measured in F rabbits ovaries. Those ovaries presented a significantly greater density/number of antral and atretic follicles and larger antral follicles without any changes in cellular proliferation or DNA fragmentation. No difference was found regarding the count of other follicle stages notably the primordial stage, the corpora lutea or AMH serum levels.

CONCLUSION

Folliculogenesis and steroidogenesis seem to be subtly altered by exposure to a human-like mixture of environmental toxicants. The antral follicle growth appears promoted by the mixture of chemicals both in their number and size, potentially explaining the increase in atretic antral follicles. Reassuringly, the ovarian reserve estimated through primordial follicles number/density and AMH is spared from any alteration. The consequences of these changes on fertility and progeny health have yet to be investigated.

Comparative evaluation of three laparoscopic cholecystectomy techniques in rabbit's model

PURPOSE

The aim of this randomized study was to compare the complications and perioperative outcome of three different techniques of laparoscopic cholecystectomy (LC). Changes in the liver function test after LC techniques were investigated. Also, we compared the degree of postoperative adhesions and histopathological changes of the liver bed.

METHODS

Thirty rabbits were divided into three groups: group A) Fundus-first technique by Hook dissecting instrument and Roeder Slipknot applied for cystic duct (CD) ligation; group B) conventional technique by Maryland dissecting forceps and electrothermal bipolar vessel sealing (EBVS) for CD seal; group C) conventional technique by EBVS for gallbladder (GB) dissection and CD seal.

RESULTS

Group A presented a longer GB dissection time than groups B and C. GB perforation and bleeding from tissues adjacent to GB were similar among tested groups. Gamma-glutamyl transferase and alkaline phosphatase levels increased (p ≤ 0.05) on day 3 postoperatively in group A. By the 15th postoperative day, the enzymes returned to the preoperative values. Transient elevation of hepatic transaminases occurred after LC in all groups. Group A had a higher adherence score than groups B and C and was associated with the least predictable technique.

CONCLUSIONS

LC can be performed using different techniques, although the use of EBVS is highly recommended.

Anti-Müllerian hormone levels in serum and testes of male dogs: relations with neuter status and bilateral abdominal cryptorchidism

Anti-Müllerian hormone (AMH) analysis has contributed to new information in the reproductive endocrinology of domestic animals, due to clinically available diagnostic tools. An accurate and rapid diagnostic method to distinguish between neutered and bilateral abdominal cryptorchid dogs is needed in veterinary practice. Therefore, this study uses an enzyme-linked immunosorbent assay to evaluate the clinical relevance of AMH analysis in peripheral blood as a diagnostic tool for dogs with suspected bilateral abdominal cryptorchidism. The possible alteration of the AMH localization in testicular tissue caused by this pathologic condition was also investigated using immunohistochemistry. Male dogs were divided into three groups of healthy intact (n = 14), healthy castrated (n = 14), and bilateral abdominal cryptorchid (n = 14) dogs. The results demonstrated a higher level of serum AMH in the cryptorchid group compared to the intact group (P < 0.01), while serum AMH levels of all castrated dogs were below the limit of detection (<0.05 ng/mL). Moreover, the percentage of positive AMH immunostaining of the intact group was less than that of the cryptorchid group (P < 0.01). A significantly positive correlation was found between serum AMH concentration and localization in testicular tissues (r = 0.93, P < 0.01). Our findings suggest that AMH levels in the peripheral blood could be used as an alternative and rapid screening method for detecting dogs with abdominal cryptorchidism.

[Diagnostic utility of the anti-Mullerian hormone in companion animals]

The anti-Mullerian hormone is a glycoprotein secreted by Sertoli cells in males and granulosa cells in females. The initial identification of this hormone in canine and feline serum was achieved in 2011. Meanwhile, a variety of studies have demonstrated its clinical significance as a tool in the endocrine diagnosis. This review summarizes the current knowledge about anti-Mullerian hormone in small animal reproduction and describes future opportunities for its diagnostic usage.

Application of Enzyme-Linked Fluorescence Assay (ELFA) to Obtain In Vivo Matured Dog Oocytes through the Assessment of Progesterone Level

Successful dog cloning requires a sufficient number of in vivo matured oocytes as recipient oocytes for reconstructing embryos. The accurate prediction of the ovulation day in estrus bitches is critical for collecting mature oocytes. Traditionally, a specific serum progesterone (P4) range in the radioimmunoassay (RIA) system has been used for the prediction of ovulation. In this study, we investigated the use of an enzyme-linked fluorescence assay (ELFA) system for the measurement of P4. Serum samples of estrus bitches were analyzed using both RIA and ELFA, and the measured P4 values of ELFA were sorted into 11 groups based on the standard concentration measured in RIA and compared. In addition, to examine the tendency of changes in the P4 values in each system, the P4 values on ovulation day (from D - 6 to D + 1) in both systems were compared. The ELFA range of 5.0-12.0 ng/mL was derived from the RIA standard range of 4.0-8.0 ng/mL. The rates of acquired matured oocytes in RIA and ELFA were 55.47% and 65.19%, respectively. The ELFA system successfully produced cloned puppies after the transfer of the reconstructed cloned oocytes. Our findings suggest that the ELFA system is suitable for obtaining in vivo matured oocytes for dog cloning.