Microfluidics is a promising approach for the facile and large-scale fabrication of monodispersed droplets for various applications in biomedicine. This technology has demonstrated great potential to address the limitations of regenerative medicine. Microfluidics provides safe, accurate, reliable, and cost-effective methods for encapsulating different stem cells, gametes, biomaterials, biomolecules, reagents, genes, and nanoparticles inside picoliter-sized droplets or droplet-derived microgels for different applications. Moreover, microenvironments made using such droplets can mimic niches of stem cells for cell therapy purposes, simulate native extracellular matrix (ECM) for tissue engineering applications, and remove challenges in cell encapsulation and three-dimensional (3D) culture methods. The fabrication of droplets using microfluidics also provides controllable microenvironments for manipulating gametes, fertilization, and embryo cultures for reproductive medicine. This review focuses on the relevant studies, and the latest progress in applying droplets in stem cell therapy, tissue engineering, reproductive biology, and gene therapy are separately evaluated. In the end, we discuss the challenges ahead in the field of microfluidics-based droplets for advanced regenerative medicine.

Premature ovarian failure (POF) leads to infertility. Numerous researchers have endeavored to enhance ovarian function through antioxidant interventions. Extract from Vitex agnus-castus (VAC) has demonstrated a protective effect. Therefore, the objective of this study was to investigate the amelioration of ovarian function following VAC treatment in a POF mouse model. In this investigation, 30 female NMRI mice were categorized into control, POF model (cyclophosphamide 120 mg/kg I.P), and experimental groups (100, 300, and 500 of VAC extract). Parameters such as body weight, vaginal smears, and follicular evaluation were examined. FSH, estradiol levels, free radicals, and the expression of the FMR1 gene were assessed. The microscopic assessment revealed that POF induced morphological alterations in ovarian tissue, whereas VAC treatment significantly ameliorated ovarian tissue conditions. The follicles number exhibited a significant reduction in the POF group; however, VAC led to an increase in follicular count and elevated estradiol levels in the treatment groups. Serum FSH levels displayed an elevation in the POF group, whereas the treatment groups exhibited a substantial reduction in FSH levels compared to the POF group. The expression of the FMR1 gene demonstrated upregulation in the POF group compared to the control group (p<0.05). Moreover, this expression significantly decreased in the 500-dose VAC group compared to the POF group (p<0.001). ROS generation exhibited a significant increase in the POF group, which was conversely mitigated in all experimental groups. Our findings underscore the potential of this extract to ameliorate POF symptoms, however, further investigations are needed.

Varicocele is a prevalent condition among the male population, representing a significant cause of male infertility. Naringenin, a flavonoid, has demonstrated significant antioxidant and anti-apoptotic properties. In this study, 24 male Wistar rats were divided into four groups: control group, sham group, a varicocele-induced rat (VCL) group, and a varicocele-with-Naringenin (20 mg/kg) treatment group (N20+C). Following a 21-day period, the rats were euthanized, and the quality of the tissue, the level of oxidative stress, the expression levels of HSP70, and the expression levels of the genes VEGF, BCL-2, caspase-3, and IL-6 in the testes were evaluated. Based on H&E images, varicocele induced tissue damage was improved by Naringenin. The expression of HSP70 in the VCl group increased in comparison to the Sham group, and in the N20+C group (p<0.001) it was lower than in the VCL group (p<0.05). MDA in the VCL group increased, SOD and TAC decreased when compared to the Control group (p<0.01), and there was no significant difference between the N20+C and the Control group. In the VCL group the expression of VEGF (p<0.05), caspase-3 (p<0.001) and IL-6 (p<0.001) genes increased in the VCL Group, and BCL-2 (p<0.05) decreased in comparison to the Control group. The expression of VEGF (p<0.05) and BCL-2 (p<0.05) increased and caspase-3 (p<0.001) and IL-6 (p<0.001) genes decreased in the N20+C group when compared to the VCL group. Naringenin has been demonstrated to reduce oxidative stress and apoptosis through the intrinsic pathway in rats with varicocele. This finding suggests that naringenin may be a promising candidate for mitigating the adverse effects associated with varicocele.