Bredigite-Based Bioactive Nerve Guidance Conduit for Pro-Healing Macrophage Polarization and Peripheral Nerve Regeneration

Our plain-English summary of Bredigite-Based Bioactive Nerve Guidance Conduit for Pro-Healing Macrophage Polarization and Peripheral Nerve Regeneration, by Y. Xuan, L. Li, X. Yin, et al (Advanced Healthcare Materials, 2024).

The study

• Authors: Y. Xuan, L. Li, X. Yin, D. He, S. Li, C. Zhang, Y. Yin, W. Xu, Z. Zhang
• Journal: Advanced Healthcare Materials
• Published: 2024;13(8):e2302994
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Structural and functional healing of peripheral nerves damaged by trauma or chronic disease remain major clinical challenges, requiring the development of an effective nerve guidance conduit (NGC). The present study investigates a NGC fabrication strategy based on bredigite (BRT, Ca7MgSi4O16) bioceramic for the treatment of peripheral nerve injury. Here, BRT bioceramic shows good biocompatibility and sustainable release of Ca2+, Mg2+, and Si4+ ions. Both BRT extracts and BRT-incorporating electrospun membranes promote the proliferation and myelination potential of RSC96 cells, as well as accelerate vascular formation by human umbilical vein endothelial cells. Notably, BRT facilitates RAW 264.7 cell polarization to the pro-healing phenotype under LPS-induced inflammatory stimulation. More importantly, the macrophages activated by BRT in turn promote RSC96 cell migration and remyelination. In a rat sciatic nerve defect model, improved electrophysiological performance and alleviated gastrocnemius muscle atrophy are observed at 12 weeks post-implantation. Further experiments verify that BRT-loaded NGC facilitates axonal regrowth and revascularization with high M2-like macrophage infiltration. These findings support the beneficial effects of BRT for creating a pro-healing immune microenvironment and orchestrating multicellular processes associated with functional nerve regeneration, indicating the potential of rationally engineered bioceramics as safe, effective, and economical materials for peripheral nerve repair.

© 2023 The Authors. Advanced Healthcare Materials published by Wiley‐VCH GmbH.

In plain English

This laboratory and animal study from China did not involve asbestos. It tested a nerve guidance conduit, a tube for bridging gaps in damaged nerves, made from a plastic (PCL) mixed with bredigite, a calcium-magnesium-silicate bioceramic. In cell cultures, bredigite extracts at 1/16 and 1/32 dilutions increased the growth of rat Schwann-type cells (RSC96), while stronger extracts (1/4 and 1/8 dilutions) were toxic to them. Under inflammatory conditions, membranes containing 5% bredigite shifted mouse macrophages toward the M2-like type, which the authors describe as pro-healing. In rats with a 10-mm sciatic nerve gap (5 rats per group), this conduit was compared with a plain PCL conduit and with nerve autografts. At 12 weeks, nerve conduction latency was shorter with the bredigite conduit than with plain PCL, though still inferior to autografts. Mean axon diameter remained lower than in the autograft and native (uncut) groups. The authors concluded the conduit had therapeutic effects on peripheral nerve injury.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory (cell culture) experiments followed by an animal experiment in a rat sciatic nerve defect model
• Who was studied: Cell lines RSC96 (rat Schwann cells), human umbilical vein endothelial cells (HUVECs) and mouse RAW 264.7 macrophages (n = 3 per group in vitro). Male Sprague–Dawley rats aged 8–10 weeks and weighing 250–320 g, n = 5 per group, in PCL conduit, BRT/PCL conduit, autograft and native control groups, at Shanghai Ninth People's Hospital.
• Exposure: Bredigite (BRT, Ca7MgSi4O16) bioceramic, used as powder extracts and as electrospun PCL membranes containing 2.5, 5 or 10 wt% BRT. A 5% BRT/PCL conduit was implanted in rats. No asbestos or other mineral fibers were studied.
• Main results:
  • BRT powder released Ca2+ at 35.57 mg/L and Si4+ at 27.29 mg/L. Mg2+ reached 3.998 mg/L after 24 h of soaking.
  • In RSC96 cells, BRT extracts at 1/16 and 1/32 dilutions significantly promoted growth, while 1/4 and 1/8 dilutions were cytotoxic.
  • In LPS-stimulated RAW 264.7 macrophages, BRT/PCL membranes had a much higher ratio of CD206-positive (M2-like) macrophages than the other groups.
  • In rats at 1 to 2 weeks after implantation, the BRT/PCL group showed more CD206+ M2-like and fewer iNOS+ M1-like macrophages than the PCL group.
  • At 12 weeks, conduction latency was significantly shorter in the BRT/PCL group than in the PCL group, but still inferior to the autograft group.
  • At 12 weeks, mean axonal diameter in the BRT/PCL group remained lower than in the autograft and native groups.
• The authors' conclusion: The authors concluded that the BRT bioceramic-based nerve guidance conduit exerted therapeutic effects on peripheral nerve injury.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Tremolite.

Medical terms in this study, explained in our Lexicon: Macrophage.

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