Biological effects different diameters of Tussah silk fibroin nanofibers on olfactory ensheathing cells

Abstract

Transplantation of olfactory ensheathing cells (OECs) has potential for treating spinal cord and brain injury. However, they are void of an extracellular matrix to support cell growth and migration. Engineering of tissue to mimic the extracellular matrix is a potential solution for neural repair. Tussah silk fibroin (TSF) has good biocompatibility and an Arg-Gly-Asp tripeptide sequence. A small number of studies have assessed the effect of the diameter of TSF nanofibers on cell adhesion, growth and migration. In the present study, TSF nanofibers with a diameter of 400 and 1,200 nm were prepared using electrospinning technology; these were then used as scaffolds for OECs. The structure and morphology of the TSF nanofibers were characterized by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy. An inverted-phase contrast microscope and SEM were used to observe the morphology of OECs on the TSF nanofibers. The effect on the adhesion of the cells was observed following crystal violet staining. The phenotype of the cells and the maximum axon length on the scaffolds were evaluated by immunostaining for nerve growth factor receptor p75. Cell proliferation and viability were assessed by an MTT assay and a Live/Dead reagent kit. The migration efficiency of OECs was observed using live-cell microscopy. The results indicated that a 400-nm TSF fiber scaffold was more conducive to OEC adhesion, growth and migration compared with a 1,200-nm TSF scaffold. The phenotype of the OECs was normal, and no difference in OEC phenotype was observe when comparing those on TSF nanofibers to those on PLL. The present study may provide guidance regarding the preparation of tissue-engineered materials for neural repair.

Advances in Electrospun Nerve Guidance Conduits for Engineering Neural Regeneration

“…Similar to SCs, they can enhance the microenvironment after nerve injury via secretion of neurotrophic factors including brain derived neurotrophic factor, glial derived neurotrophic factor, and nerve growth factor [65,66], as well as extracellular matrix molecules, which together can indirectly activate endogenous SCs [60,[67][68][69]. Compared to SCs, OECs express higher levels of macrophage migration inhibitory factor (MIF), which prevents the infiltration of macrophages into the injury site and thus OECs can modulate the inflammatory response [65,66,70].…”

Comprehensive Review on Silk at Nanoscale for Regenerative Medicine and Allied Applications

“…Results indicated that the diameter of the fibers played an important role in guiding cell adhesion, growth, and migration in vitro . In similar lines, culturing of nonmulberry silk nanofibrous mats (tasar silk) with OECs also displayed greater OEC adhesion, growth, and migration on 400 nm diameter of nanofibers (Figure I and II) . On the other hand, structural resemblance of biomineralized nanosilk fibroin films seeded with bone marrow stromal cells to the natural bone has been successfully exploited to induce spinal fusion in rat models .…”

“…In similar lines, culturing of nonmulberry silk nanofibrous mats (tasar silk) with OECs also displayed greater OEC adhesion, growth, and migration on 400 nm diameter of nanofibers (Figure 4I and II). 132 On the other hand, structural resemblance of biomineralized nanosilk fibroin films seeded with bone marrow stromal cells to the natural bone has been successfully exploited to induce spinal fusion in rat models. 133 Although the bone volume, relative strength and stiffness, and the bone fusion rate of the cell seeded films were slightly less than those of the autograft, no significant difference was documented.…”

“…( II ) Images representing alignment of cultured OECs with the nanofibers made up of Tussah silk. ( III – IV ) Silk fibroin electrospun mats as bioactive guides for nerve regeneration [Panels I – II are reprinted with permission from ref . Copyright 2018 Wu et al Panels III – IV are reprinted with permission from ref .…”