De novo reconstruction of a functional in vivo-like equine endometrium using collagen-based tissue engineering.

To better understand molecular aspects of equine endometrial function, there is a need for advanced in vitro culture systems that more closely imitate the intricate 3-dimensional (3D) in vivo endometrial structure than current techniques. However, development of a 3D in vitro model of this complex tissue is challenging. This study aimed to develop an in vitro 3D endometrial tissue (3D-ET) with an epithelial cell phenotype optimized by treatment with a Rho-associated protein kinase (ROCK) inhibitor. Equine endometrial epithelial (eECs) and mesenchymal stromal (eMSCs) cells were isolated separately, and eECs cultured in various concentrations of Rock inhibitor (0, 5, 10 µmol) in epithelial medium (EC-medium) containing 10% knock-out serum replacement (KSR). The optimal concentration of Rock inhibitor for enhancing eEC proliferation and viability was 10 µM. However, 10 µM Rock inhibitor in the 10% KSR EC-medium was able to maintain mucin1 (Muc1) gene expression for only a short period. In contrast, fetal bovine serum (FBS) was able to maintain Muc1 gene expression for longer culture durations. An in vitro 3D-ET was successfully constructed using a collagen-based scaffold to support the eECs and eMSCs. The 3D-ET closely mimicked in vivo endometrium by displaying gland-like eEC-derived structures positive for the endometrial gland marker, Fork headbox A2 (FOXA2), and by mimicking the 3D morphology of the stromal compartment. In addition, the 3D-ET expressed the secretory protein MUC1 on its glandular epithelial surface and responded to LPS challenge by upregulating the expression of the interleukin-6 (IL6) and prostaglandin F synthase (PGFS) genes (P < 0.01), along with an increase in their secretory products, IL-6 (P < 0.01) and prostaglandin F2alpha (PGF2α) (P < 0.001) respectively. In the future, this culture system can be used to study both normal physiology and pathological processes of the equine endometrium.

Effects of freeze-drying on the quality and fertilising ability of goat sperm recovered from different parts of the epididymis.

Lyophilisation is an alternative method for sperm preservation. The aim of this study was to evaluate the effects of freeze-thawing (F/T) and freeze-drying (F/D) on the quality of epididymal goat sperm. Sperm from each region of the epididymis (caput, corpus and cauda) were collected and evaluated for the expression of phospholipase C zeta (PLC-ζ), protamine 1 (PRM1), transition protein 1 (TNP1) and 2 (TNP2). The effects of F/T and F/D on sperm quality in terms of PLC-ζ expression, chromatin stability (Chromomycin A3; CMA3) and DNA integrity were examined. The fertilising ability after intracytoplasmic sperm injection (ICSI) was also tested. Fresh sperm existed PLC-ζ, PRM1, TNP1 and TNP2, irrespective of the regions of the epididymis. However, different patterns of PLC-ζ expression were found. Although PRM1, TNP1, TNP2 were still expressed after F/T or F/D, only F/T could preserve the presence of PLC-ζ. For fresh sperm, caput epididymal sperm had the lowest evidence of chromatin stability when compared to sperm harvested from other regions of the epididymis. The F/T and F/D further increased the numbers of CMA3-positive sperm (P < 0.001). In all cases, no CMA3 staining was observed in caudal epididymal sperm. The caudal epididymal sperm had significantly greater proportions of sperm with intact DNA compared with caput and corpus epididymal sperm, especially when F/T and F/D were performed. The fertilisation rates of F/D sperm tended to decrease when compared with F/T sperm (4.2 ± 3.2 vs. 13.6 ± 9.0, P = 0.08). It is concluded that the sperm recovered from the caudal epididymis is suitable for freezing and lyophilisation. However, poor fertilisation rates of F/D sperm were coincidently observed, with a deficit demonstration of PLC-ζ.