Use of ultrasound imaging for the diagnosis of abnormal uterine bleeding in the bonnet macaque ( Macaca radiata).

Ultrasound is a powerful, low-cost, non-invasive medical tool used by laboratory animal veterinarians for diagnostic imaging. Sonohysterography and transvaginal ultrasound are frequently used to assess uterine anomalies in women presenting with abnormal uterine bleeding (AUB). In the present study, we have evaluated the abdominal ultrasound of bonnet monkeys ( n = 8) showing spontaneous ovulatory ( n = 5) and anovulatory ( n = 3) AUB. The ovulatory ( n = 5) macaques showed cyclic AUB for 7-8 days. The anovulatory ( n = 3) macaques had irregular AUB with menstrual cycles of 40-45 days. The B-mode abdominal, colour Doppler and 3D ultrasound scans were performed during the proliferative phase of the menstrual cycle. Ultrasound examination revealed endometrial polyps in five macaques and endometrial hyperplasia in three animals. The width and length of endometrial polyps was around 0.5-1 cm (average 0.51 ± 0.23 cm × 0.96 ± 0.16 cm) with significant increase in endometrial thickness ( P < 0.0002). 3D ultrasound also showed a homogeneous mass in the uterine cavity and colour Doppler ultrasound showed increased vascularity in the endometrial polyps. Endometrial hyperplasia characteristically appeared as a thickened echogenic endometrium ( P < 0.0002). This study demonstrates the use of non-invasive ultrasound techniques in the diagnosis of AUB in macaques.

Expression of endometrial protein kinase a during early pregnancy in bonnet monkeys (Macaca radiata).

Embryo-induced signaling pathways are considered to be important for initiation and sustenance of pregnancy. However many of these pathways remain to be deciphered in primates. In the present study, differential display RT-PCR was used to identify genes or gene fragments that are differentially expressed in endometrium of bonnet monkeys (Macaca radiata) on Day 6 of pregnancy. Of several fragments found to be differentially expressed, a fragment of 567 base pair (named GG1) was characterized in detail. GG1 was highly represented in endometrium of pregnant animals compared with that of nonpregnant animals. Sequencing analysis revealed homology of this fragment to exons 7, 8, 9, and 10 and surprisingly to intron 6 of cAMP-dependent protein kinase A (PKA) regulatory type I alpha (tissue-specific extinguisher 1) (PRKAR1A). The increased expression of this fragment in gestational endometrium was confirmed by quantitative PCR studies. Two transcripts of 3.0 kilobase (kb) and 1.5 kb were detected in Northern blot probed with labeled GG1. Protein expressions of alpha regulatory (PRKAR1A) and alpha catalytic (PRKCA) subunits of PKA were also higher in gestational endometrium compared with that in nongestational endometrium. Further in vitro studies using human endometrial explants demonstrated regulation of PRKAR1A (or GG1) and prostaglandin-endoperoxide synthase 2 or cyclooxygenase 2 (PTGS2) by estradiol. This is the first study to date on the differential expression of PKA in primate endometrium during early pregnancy and its in vitro regulation by estradiol.

Role of progesterone in structural and biochemical remodeling of endometrium.

The endometrial response to the varying levels of ovarian steroids is exhibited as alterations in its form and function. These changes in endometrial morphology and physiology, especially those observed during the implantation window are prerequisites to support embryo attachment and invasion. However the state of endometrial receptivity to embryo results from an operative network of several molecular events triggered by estrogen, progesterone and probably some other factors, yet to be discovered. It is well established that estrogen and progesterone are the critical endocrine determinants of endometrial functions. However the precise delineation of hormone driven events and their interaction is yet to be ascertained. Several attempts have been made to understand these cascades, however most of these studies have been conducted in vitro using one or the other component of endometrial tissues. We have attempted to investigate in vivo morphological and biochemical/molecular changes in endometrium in response to neutralization of progesterone synthesis/ function in two primate animal models. In one of the models, ovariectomized rhesus monkeys, artificial menstrual cycles were simulated and subsequent effects on the _expression of various genes were investigated in presence and absence of sufficient progesterone levels. The results coincided with those observed in the endometrium of the other model, bonnet monkeys presenting normal hypothalamus-ovarian-pituitary function but displaying retarded endometrial growth due to blocked progesterone receptor. A significant decline was observed in the expression of transforming growth factor beta, transforming growth factor beta receptor, leukaemia inhibitory factor, whereas no remarkable changes were observed in the expression of estrogen receptor and progesterone receptors in response to neutralization of progesterone synthesis/function in these two animal models. Taking support from the inferences drawn from previously published in vitro studies and our data from in vivo studies conducted in these two models, we propose a hypothesis supporting a potential link between the expressions of transforming growth factor beta, leukaemia inhibitory factor, cyclooxygenases and integrins.