Epigallocatechin Gallate-Modified Gelatins with Different Compositions Alter the Quality of Regenerated Bones

Abstract

Bone quality is a significant indicator of the result of bone treatments. However, information regarding the quality of regenerated bones is limited. The study investigates the effect of different compositions of vacuum heated epigallocatechin gallate-modified gelatins sponge (vhEGCG-GS) on the quality of regenerated bones in critical size defects (9 mm) of rat calvariae. Five different compositions of vhEGCG-GSs containing the same amount of EGCG and different amounts of gelatin were tested. Following four weeks after implantation, the harvested regenerated bones were evaluated by using micro-computed tomography analysis, histological evaluation (hematoxylin-eosin and Villaneueva Goldner staining), picrosirius red-staining with polarized microscopic observation for collagen maturation, and Fourier transform infrared spectroscopy microscopy and imaging analysis for mineral-matrix ratio. The results indicated that increasing content of gelatin in the vhEGCG-GSs promoted bone and osteoid formation but yielded porous bones. Furthermore, tissue mineral density decreased and the maximum mineral-matrix ratio increased. In contrast, vhEGCG-GSs containing smaller amount of gelatin formed mature collagen matrix in the regenerated bones. These results suggest that the alteration of composition of vhEGCG-GSs affected the bone forming capability and quality of regenerated bone and provides valuable insight for the fabrication of new bone substitute materials.

Augmentation of Bone Regeneration by Depletion of Stress-Induced Senescent Cells Using Catechin and Senolytics

“…The rats were housed in a ventilated room with a 12 h light/dark cycle during the experiments. At the center of their calvaria, 9-mm-sized bone defects, commonly recognized as the critical size defect, were created using a trephine bar as reported previously [ 45 ]. During surgery, the rats were anesthetized with an intraperitoneal injection of a mixture of medetomidine hydrochloride (0.15 mg/kg; Domitor; Zenoaq, Fukushima, Japan), midazolam (2 mg/kg; Midazolam Sandoz, Sandoz KK, Yamagata, Japan), and butorphanol tartrate (2.5 mg/kg; Vetorphale, Meiji Seika Parma Co., Ltd., Tokyo, Japan).…”

Sustained Release of Catechin from Gelatin and Its Effect on Bone Formation in Critical Sized Defects in Rat Calvaria

“…The AC-vhEGCG-GS was prepared according to previous methods 18) . Briefly, 0.07 mg of EGCG, 100 mg of gelatin, 27.5 μl of NMM, and 69.2 mg DMT-MM were mixed in 5 ml of MilliQ water at 23 o C. The dose of EGCG and gelatin determined in our previous study to result in superior bone formation was used 18,24) . The resulting solution was dialyzed using Spectra/Por7 MWCO 1000 (Spectrum Labs, Inc., CA, USA) to remove residual reagents and diluted to 10 ml with MilliQ water.…”

“…The rats were anesthetized by intraperitoneal injection of a mixture of medetomidine hydrochloride (Domitor; Zenoaq, Fukushima, Japan), midazolam (Midazolam Sandoz; Sandoz K.K., Yamagata, Japan), and butorphanol tartrate (Vetorphale; Meiji Sika Parma Co., Ltd., Tokyo, Japan). Bone defects (9 mm) were prepared at the center of the calvaria using a trephine bar as reported previously 24) . Ten sponges (each sponge: 3 × 2 mm; D × H) were implanted in three defected calvaria per group.…”

“…4 and 5). Our previous study showed that in defects with no implantation (negative control) there was a small amount of newly formed bone in the defect for up to 4 w 18,24) . The defects treated with AC-vhEGCG-GSs showed a greater radio-opacity than those treated with NC-vhEGCG-GSs (Fig.…”

“…More recently, we showed that the bone-forming ability of vacuum-heated AC-EGCG-GS (AC-vhEGCG-GS) was greater than that of vacuum-heated gelatin sponges (without EGCG) in critical-sized bone defects (9 mm of diameter) of rat calvaria 18) . Alteration of the quantity of EGCG and gelatin in AC-vhEGCG-GSs affected the bone formation results 18,24) . Although both AC-vhEGCG-GSs and vacuum-heated gelatin sponges successfully served as scaffolds for cells, the combination of AC-vhEGCG-GS with multipotent progenitor cells (dedifferentiated fat cells or adipose-derived stem cells) formed more bone in the congenital bone defects of rat jaws than the combination of vacuum-heated gelatin sponge with the above cells 25) .…”