An animal experimental study of porous magnesium scaffold degradation and osteogenesis

Abstract

Our objective was to observe the biodegradable and osteogenic properties of magnesium scaffolding under in vivo conditions. Twelve 6-month-old male New Zealand white rabbits were randomly divided into two groups. The chosen operation site was the femoral condyle on the right side. The experimental group was implanted with porous magnesium scaffolds, while the control group was implanted with hydroxyapatite scaffolds. X-ray and blood tests, which included serum magnesium, alanine aminotransferase (ALT), creatinine (CREA), and blood urea nitrogen (BUN) were performed serially at 1, 2, and 3 weeks, and 1, 2, and 3 months. All rabbits were killed 3 months postoperatively, and the heart, kidney, spleen, and liver were analyzed with hematoxylin and eosin (HE) staining. The bone samples were subjected to microcomputed tomography scanning (micro-CT) and hard tissue biopsy. SPSS 13.0 (USA) was used for data analysis, and values of P<0.05 were considered to be significant. Bubbles appeared in the X-ray of the experimental group after 2 weeks, whereas there was no gas in the control group. There were no statistical differences for the serum magnesium concentrations, ALT, BUN, and CREA between the two groups (P>0.05). All HE-stained slices were normal, which suggested good biocompatibility of the scaffold. Micro-CT showed that magnesium scaffolds degraded mainly from the outside to inside, and new bone was ingrown following the degradation of magnesium scaffolds. The hydroxyapatite scaffold was not degraded and had fewer osteoblasts scattered on its surface. There was a significant difference in the new bone formation and scaffold bioabsorption between the two groups (9.29±1.27 vs 1.40±0.49 and 7.80±0.50 vs 0.00±0.00 mm3, respectively; P<0.05). The magnesium scaffold performed well in degradation and osteogenesis, and is a promising material for orthopedics.

Bone biomaterials and interactions with stem cells

“…As for Mg and its alloys, the porous structure is mainly prepared by space holding, 301 , 302 mechanical drilling, 303–305 laser drilling 306 , 307 , and selective laser melting (SLM). 308 Among these methods, mechanical drilling and laser drilling can only prepare pores with a monotonous shape and structure, as well as a narrow pore diameter distribution and low porosity.…”

Porous magnesium-based scaffolds for tissue engineering

“…Liu et al [89] studied the in vivo biodegradability and osteogenicity of porous magnesium scaffolds by implantation inside the femoral condyle of male New Zealand white rabbits [89].…”

“…Although surface modifications was used to reduce the degradation rate and to decrease hydrogen generation, formation of mild swelling in rabbits knees starting from 2 weeks and persisting for 2 months, indicated inadequate thickness of magnesium oxide and surface treatment [89]. However, these findings show that even fast degrading magnesium scaffolds demonstrate good biocompatibility, suitable inflammatory response, and bone regeneration, which makes open porous magnesium scaffolds good candidates for bone and cartilage tissue engineering [45].…”

Development of magnesium implants by application of conjoint‐based quality function deployment

“…A pH increase above 7.8 may result in alkaline poisoning (Song, ) and inflammatory responses (Li et al, ; Razavi et al, ), which explains the background of the requirement. Moderate hydrogen release : The corrosion of magnesium‐based implants forms hydrogen (Witte et al, ). Despite the rapid diffusion and absorption (Aghion, Levy, & Ovadia, ; Dziuba et al, ; Gu, Xie, Li, Zheng, & Qin, ; Hänzi, Gerber, Schinhammer, Löffler, & Uggowitzer, ; Hou et al, ; Liu, Yang, Tan, Li, & Zhang, ; Pichler et al, ; Razavi et al, ; Song & Atrens, ; Witte et al, ; Witte et al, ) of this gas, a moderate and controlled release mechanism is required during the degradation process. Rapid production of large amounts of hydrogen can promote the loss of mechanical integrity due to hydrogen embrittlement (Choudhary & Singh Raman, ; Gu, Zhou, Zheng, Cheng, et al, ; Jafari et al, ; Kannan, ), the formation of temporary gas cavities (Witte et al, ) and/or the impairment of blood circulation (Song, ).…”