Utilizing epoxy Bletilla striata polysaccharide collagen sponge for hemostatic care and wound healing.

Hemostatic materials that are lightweight and possess good blood absorption performance have been widely considered for use in modern wound care. Natural hemostatic ingredients derived from traditional Chinese medicine have also received extensive attention. Bletilla polysaccharides are valued by researchers for their excellent hemostatic performance and good reactivity. Collagen is favored by researchers due to its high biocompatibility and low immunogenicity. In this study, Bletilla striata polysaccharide, the main hemostatic component of Bletilla striata, was activated by epoxy groups, and epoxidized Bletilla striata polysaccharide (EBSP) was prepared. Then, EBSP was crosslinked with collagen under alkaline conditions, and a new hemostatic material that was an epoxidized Bletilla polysaccharide crosslinked collagen hemostatic sponge was prepared. We demonstrated that endowing collagen with better hemostatic performance, cytocompatibility, and blood compatibility does not destroy its original three-stranded helical structure. Compared with the medical gauze, hemostasis time was shorter (26.75 ±â€¯2.38 s), and blood loss was lower (0.088 ±â€¯0.051 g) in the rat liver injury hemostasis model. In the rat model of severed tail hemostasis, hemostasis time was also shorter (47.33 ±â€¯2.05 s), and the amount of blood loss was lower (0.330 ±â€¯0.122 g). The sponge possessed good hemostatic and healing performance.

Amniotic membrane attenuates heterotopic ossification following high-dose bone morphogenetic protein-2 treatment of segmental bone defects.

Treatment of large bone defects with supraphysiological doses of bone morphogenetic protein-2 (BMP-2) has been associated with complications including heterotopic ossification (HO), inflammation, and pain, presumably due to poor spatiotemporal control of BMP-2. We have previously recapitulated extensive HO in our rat femoral segmental defect model by treatment with high-dose BMP-2 (30 µg). Using this model and BMP-2 dose, our objective was to evaluate the utility of a clinically available human amniotic membrane (AM) around the defect space for guided bone regeneration and reduction of HO. We hypothesized that AM surrounding collagen sponge would attenuate heterotopic ossification compared with collagen sponge alone. In vitro, AM retained more BMP-2 than a synthetic poly(ε-caprolactone) membrane through 21 days. In vivo, as hypothesized, the collagen + AM resulted in significantly less heterotopic ossification and correspondingly, lower total bone volume (BV), compared with collagen sponge alone. Although bone formation within the defect was delayed with AM around the defect, by 12 weeks, defect BVs were equivalent. Torsional stiffness was significantly reduced with AM but was equivalent to that of intact bone. Collagen + AM resulted in the formation of dense fibrous tissue and mineralized tissue, while the collagen group contained primarily mineralized tissue surrounded by marrow-like structures. Especially in conjunction with high doses of growth factor delivered via collagen sponge, these findings suggest AM may be effective as an overlay adjacent to bone healing sites to spatially direct bone regeneration and minimize heterotopic ossification.

* Early and Marked Enhancement of New Bone Quality by Alendronate-Loaded Collagen Sponge Combined with Bone Morphogenetic Protein-2 at High Dose: A Long-Term Study in Calvarial Defects in a Rat Model.

Choice of appropriate biomaterial is a key factor for the success of recombinant human bone morphogenetic protein (rhBMP)-2 therapy. Inspired by osteogenic cell-differentiating and osteoclast-suppressing capabilities of alendronate (ALN), we manufactured a composite type of ALN-loaded collagen sponge (ALN-CS), which controls the early detrimental effect of high-dose rhBMP-2. This study aimed to evaluate ALN-CS as a high-dose rhBMP-2 carrier by investigating its initial biomolecular effect and efficacy on intramembranous ossification at 1, 4, 8, and 24 weeks using a rat calvarial defect model compared with nonloaded CS. The in vitro rhBMP-2 release in the ALN-CS showed a low initial burst and steady release phase during the rest period despite lack of calcium compared with that in CS alone. ALN release showed the same tendency as rhBMP-2 release. In vitro characterization showed that osteoblast differentiation and mineralization of mesenchymal stromal cells were more enhanced with ALN-CS. The ALN-CS-BMP group showed higher expression of bone-forming and -resorbing markers in vivo than the CS-BMP group after the first 7 days, which might be attributable to the relatively large amount of rhBMP-2 remaining. However, osteoclast activation in the ALN-CS-BMP group was significantly reduced compared with the CS-BMP group. Radiological and histological analyses revealed that ALN-CS-BMP promoted early and dense ossification at the initial defect, with 100% greater bone mass, 20% greater bone density, and less fatty marrow tissue than CS-BMP, which continued during the whole healing period. However, CS or ALN-CS alone failed to show complete defect closure even at the 24-week healing interval. Our results demonstrate that ALN-CS has remarkable advantages over CS alone in high-dose BMP-2 delivery, with potent suppression of resorption, early and dense ossification at the target area with less fatty marrow formation, and continuation of bone quality over the long term, which highlights its great clinical potential as a rhBMP carrier for bone regeneration at intramembranous ossification sites.

Low-level laser therapy (780 nm) combined with collagen sponge scaffold promotes repair of rat cranial critical-size defects and increases TGF-ß, FGF-2, OPG/RANK and osteocalcin expression.

The aim of this study was to evaluate the effect of collagen sponge scaffold (CSS) implantation associated with low-level laser therapy (LLLT) on repairing bone defects. A single 5-mm cranial defect was surgically created in forty Wistar rats, which then received one of the following four interventions (n = 10 per group): no treatment (G0); bone defect implanted with collagen sponge scaffold (CSS) alone (G1); defect treated with low-level laser therapy (LLLT) (wavelength 780 nm; total energy density 120 J/cm2 ; power 50 mW) alone (G2); and CSS associated with LLLT treatment (G3). After surgery, animals in each group were euthanized at 21 days and 30 days (n = 5 per euthanasia time group). Bone formation was monitored by X-ray imaging analysis. Biopsies were collected and processed for histological analysis and immunohistochemical evaluation of transforming growth factor-beta (TGF-ß), fibroblast growth factor-2 (FGF-2), osteoprotegerin (OPG) and receptor activator of nuclear factor ƙ (RANK). Osteocalcin (OCN) was detected by immunofluorescence analysis. Compared to the G0 group, defects in the 30-day G3 group exhibited increased bone formation, both by increase in radiopaque areas (P < 0.01) and by histomorphometric analysis (P < 0.001). The histopathological analysis showed a decreased number of inflammatory cells (P < 0.001). The combined CCS + LLLT (G3) treatment also resulted in the most intense immunostaining for OPG, RANK, FGF-2 and TGF-ß, and the most intense and diffuse OCN immunofluorescent labelling at 30 days postsurgery (G3 vs. G0 group, P < 0.05). Therefore, the use of CCS associated with LLLT could offer a synergistic advantage in improving the healing of bone fractures.