Skin, the body's protective barrier, prevents water loss and shields us from numerous diseases and environmental stimuli [1, 2]. The skin is composed of an epithelial layer and an underlying dermal layer with characteristic undulating microstructures called rete ridges (RRs) in the dermal-epidermal junction (DEJ) [3], [4], [5], [6], [7]. Porcine skin, like human skin, contains RRs [8]; however, the epidermis of other animals, such as mice and most non-human primates, generally lacks prominent RRs [9], [10], [11], [12], [13].

RRs are essential for enhancing the skin's mechanical strength and maintaining skin homeostasis [1, 14, 15]. In human skin, minor wounds heal efficiently without treatment. However, full-thickness wounds do not regenerate RRs [10, 16], which affects the quality of scar tissue and the integrity of skin function at the wound site [1]. Therefore, the morphology of RRs is one of the most distinguishing properties of intact and regenerated skin in humans [16, 17], and the depth and architecture of RRs reflect the quality of wound healing [18, 19]. Therefore, in the field of skin wound repair, more attention needs to be given to the formation mechanisms and regeneration technologies pertaining to RRs.

Advanced technologies in tissue engineering and regenerative medicine [3, 6, 20] make it possible to develop artificial skin substitutes for transplantation therapy in cases of severe injuries such as burns and chronic diabetes [3]. However, most of these tissue-engineered skin (TES) transplants commonly lack RR microstructures at the DEJ, and it is difficult to duplicate the cross-talk between dermal and epidermal components. This weakens the adhesion between these layers, reducing the efficiency of skin tissue repair and regeneration [20]. Therefore, it is important to reconstruct RR microstructures in TES transplants [15].

The repair of the RR structure in damaged skin is often neglected due to the insufficient understanding of the significance of RR structure and the limited repair technologies available for damaged skin. Therefore, it is crucial to investigate the characteristics and regeneration technologies required for maintaining RR structure. This review summarizes the existing studies on the structural features, function, and morphogenesis of RRs, and the factors influencing RR morphology. In addition, it highlights the regeneration technology for RR structures in TES and its application in skin repair and regeneration.