The innate and adaptive immune systems rely on the skin for various purposes, serving as the primary defense against harmful environmental elements. However, skin lesions may lead to undesirable consequences such as scarring, accelerated skin aging, functional impairment, and psychological effects over time. The rising popularity of mesenchymal stromal cells (MSCs) for skin wound treatment is due to their potential as a promising therapeutic option. MSCs offer advantages in terms of differentiation capacity, accessibility, low immunogenicity, and their central role in natural wound-healing processes. To accelerate the healing process, MSCs promote cell migration, angiogenesis, epithelialization, and granulation tissue development. Oxygen plays a critical role in the formation and expansion of mammalian cells. The term “normoxia” refers to the usual oxygen levels, defined at 20.21 percent oxygen (160 mm of mercury), while “hypoxia” denotes oxygen levels of 2.91 percent or less. Notably, the ambient O₂ content (20%) in the lab significantly differs from the 2%–9% O₂ concentration in their natural habitat. Oxygen regulation of hypoxia-inducible factor-1 (HIF-1) mediated expression of multiple genes plays a crucial role in sustaining stem cell destiny concerning proliferation and differentiation. This study aims to elucidate the impact of normoxia and hypoxia on MSC biology and draw comparisons between the two. The findings suggest that expanding MSC-based regenerative treatments in a hypoxic environment can enhance their growth kinetics, genetic stability, and expression of chemokine receptors, ultimately increasing their effectiveness.

Background: Tissue engineering is a new approach to reconstruction and/or regeneration of lost or damaged tissue. The purpose of this study was to fabricate the polycaprolactone (PCL) random nanofiber scaffold as well as evaluation of the cell viability, adhesion, and proliferation of rat nestin-positive hair follicle stem cells (HFSCs) in the graft material using electrospun PCL nanofiber scaffold in regeneration medicine. Materials and Methods: The bulge HFSCs was isolated from rat whiskers and cultivated in Dulbecco's modified Eagle's medium/F12. To evaluate the biological nature of the bulge stem cells, flow cytometry using nestin, CD34 and K15 antibodies was performed. Electrospinning was used for the production of PCL nanofiber scaffolds. Furthermore, scanning electron microscopy (SEM) for HFSCs attachment, infiltration, and morphology, 3-(4, 5-di-methylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay for cell viability and cytotoxicity, tensile strength of the scaffolds mesh, and histology analysis were used. Results: Flow cytometry showed that HFSCs were nestin and CD34 positive but K15 negative. The results of the MTT assay showed cell viability and cell proliferation of the HFSCs on PCL nanofiber scaffolds. SEM microscopy photographs indicated that HFSCs are attached and spread on PCL nanofiber scaffolds. Furthermore, tensile strength of the scaffolds mesh was measured. Conclusion: The results of this study revealed that modified PCL nanofiber scaffolds are suitable for HFSCs seeding, attachment, and proliferation. Furthermore, HFSCs are attached and proliferated on PCL nanofiber scaffolds.

Biodegradable nanoparticulate carriers are potentially applicable compounds in the administration of therapeutic agents and drug delivery. They have received much attention due to their biological characteristics such as biodegradability, biocompatibility, and bioadhesive. The objectives of this work are first, investigating the impact of two important parameters (i.e. chitosan or sodium tripolyphosphate (TPP) solution concentration and chitosan to TPP mass ratio) on the chitosan nanoparticles (CNPs) formation by ionic-gelation method and then, the synthesis and characterization of chitosan-based, biodegradable drug-loaded nanoparticles in the encapsulation of novel 4′-(4-(methylsulfonyl)phenyl)-3′-(3,4,5-trimethoxyphenyl)-4′H-spiro[indene-2,5′-isoxazol]-1(3H)-one (MTS) indanonic tricyclic spiroisoxazoline, which is a potent anticancer drug. The particle size, shape, zeta potential, drug loading capacity, in vitro release characteristics, and stability of the formulated drug-loaded nanoparticles of the different drug:carrier ratio has been studied. The results indicated that the particle size increased at the higher chitosan or TPP concentration while the mass ratio did not appear to be a significant parameter during the cross-linking process. The particle diameter and zeta potential of CNPs including MTS were approximately in the range of 256–350 nm and 24.08–38.70 mV, respectively. The entrapment efficiency steadily increased with increasing the concentration of the polymer in formulizations. Throughout 24 h, the in vitro release behavior was provided a sustained release from all the drug-loaded formulizations. The optimal formulization of CNPs based on drug content with a drug:carrier ratio of 1:2 did not change appreciably during 60-day storage at either 4 °C or the ambient temperature.