Sildenafil citrate-loaded targeted nanostructured lipid carrier enhances receptivity potential of endometrial cells via LIF and VEGF upregulation.

The main objective of this research is to prepare sildenafil citrate (SC)-loaded arginyl-glycyl-aspartic acid (RGD)-containing nanostructured lipid carrier (SC-loaded NLC-RGD) and evaluate their effects on the receptivity potential of endometrial cells. Hot homogenization method was used to prepare SC-loaded NLC-RGD. Then, size, drug encapsulation, and morphology of prepared nanoparticles were studied by photon correlation spectroscopy technic, ultrafiltration method, and scanning electron microscopy, respectively. Subsequently, the influence of SC-loaded NLC-RGD on endometrial receptivity was evaluated by in vitro implantation assay. Finally, expression of vascular endothelial growth factor (VEGF), leukemia inhibitory factor (LIF), and integrin beta 3 (as endometrial receptivity markers) was assessed in SC-loaded NLC-RGD-treated endometrial cells by reverse transcription polymerase chain reaction (RT-PCR). Particles with a nano-size diameter (92.7 nm), appropriate polydispersity index (0.21), spherical morphology, and acceptable loading efficiency were prepared. In vitro implantation assay showed that SC, SC-loaded NLC, and SC-loaded NLC-RGD improve the rate of endometrial attachment potential by 1.6 ± 0.4, 1.7 ± 0.3, and 2.3 ± 0.3 times, respectively. Analysis of RT-PCR results showed the enhancing mRNA of LIF and VEGF in SC-treated endometrial cells. Results also confirmed the higher influence of SC-loaded NLC-RGD on gene expression patterns in comparison to SC. Using NLC-RGD as a carrier to deliver SC to endometrial cells is an effective approach to improve endometrial receptivity. Upregulation of LIF and VEGF is the probable mechanism by which SC enhances the endometrial receptivity potential.