# Investigation of Osteopontin (OPN) Expression in Dromedary Camel (Camelus dromedarius) in the First Trimester of Pregnancy

## TL;DR

This study explores how Osteopontin (OPN) supports reproduction in dromedary camels during early pregnancy.

## Contribution

The study confirms OPN expression in dromedary camels during the early first trimester, suggesting its role in embryo attachment and placentation.

## Key findings

- OPN mRNA expression increases gradually in endometrial and fetal membranes during early camel pregnancy.
- OPN protein is predominantly found in uterine luminal epithelium and fetal trophectoderm.
- OPN supports embryo attachment, implantation, and placenta development in dromedary camels.

## Abstract

The dromedary camel, which is economically and socially important, faces reproductive challenges such as early embryonic loss and a low reproductive rate. This study investigated the role of Osteopontin (OPN), a crucial protein involved in reproduction across many species, in the first trimester of camel pregnancy. Endometrial and fetal membranes issue samples were collected from the uteruses and conceptuses of eight pregnant camels (Days 70–110 of pregnancy) to examine the expression of OPN by using quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC). The results showed a gradual increase in OPN mRNA expression with advancing pregnancy in both endometrial and fetal membranes tissues. OPN protein was predominantly found in the uterine luminal epithelium (LE) and fetal trophectoderm (Tr), stroma, and uterine glands. These findings suggest that OPN plays a key role in the successful reproduction of the dromedary camel by aiding in processes like embryo attachment, implantation, and the development of the placenta. Understanding this mechanism can help improve breeding success and overcome reproductive obstacles in this valuable species.

Osteopontin (OPN) is a phosphorylated acidic glycoprotein that serves various purposes across various systems. Principally, it aids in adhesion and signaling. It is an important protein related to reproduction, which has been discovered in several species, among which is the dromedary camel, where it has been detected in the endometrium and conceptuses at the time of implantation. The objective of this research is to investigate and examine the expression patterns of OPN mRNA and protein in both endometrial uterine horns with their associated fetal membranes during the first trimester of camel pregnancy. Endometrial and fetal membranes were collected from eight pregnant female camels during the first trimester of pregnancy (Days 70–110 of pregnancy). The temporospatial expression of OPN was studied in endometrial tissues and their conceptuses from the left uterine horn (LUH) and right uterine horn (RUH) using quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC) techniques. The results showed a gradual increase in OPN mRNA expression with advancing pregnancy in both LUH and RUH of endometrial and fetal membranes tissue. OPN protein was predominantly found in the uterine luminal epithelium (LE) and fetal trophectoderm (Tr), stroma, and uterine glands. In conclusion, our findings demonstrate that OPN is consistently present in both the endometrium and fetal membranes throughout the first trimester of pregnancy. This observation advances previous knowledge by confirming OPN expression even during the early first trimester, suggesting its crucial role in supporting embryo attachment, implantation, and placentation processes in the dromedary camel.