# A Borophosphate Glass Doped with Cobalt Oxide Improves Skeletal Muscle Structure and Function in Myopathic Mice

## TL;DR

A new borophosphate glass doped with cobalt oxide improves muscle strength and structure in mice with a muscle disease.

## Contribution

A novel inorganic biomaterial (CoO-TRIM) is shown to enhance muscle regeneration and function in myopathic mice.

## Key findings

- CoO-TRIM injection increased muscle force and myofiber size in myopathic mice up to 70 days post-treatment.
- VEGF levels were elevated in treated mice, leading to increased muscle vascularity.
- Inflammation markers increased temporarily but normalized by 70 days without long-term negative effects.

## Abstract

Skeletal muscle myopathy remains a significant cause of disability with limited treatment strategies. Advancements in tissue engineering have led to the development of borophosphate bioactive glasses (BPBGs) capable of enhancing skeletal muscle structure and function. Using a mouse model of severe myopathy (D2.mdx), we investigated muscle force, regeneration, angiogenesis and inflammation at 14, 70 and 140 days post-treatment (dpt). Tibialis anterior (TA) muscles of D2.mdx mice that received a single injection of cobalt oxide-doped BPBG (CoO-TRIM) particles exhibit greater active force, myofiber size, and regeneration through 70 dpt compared to control D2.mdx mice injected with Saline. Vascular endothelial growth factor (VEGF) was elevated up to 70 dpt in D2.mdx CoO-TRIM mice followed by increased muscle vascularity. As a marker of inflammation, interleukin (IL)-6 increased in D2.mdx CoO-TRIM mice compared to D2.mdx Saline controls at 14 dpt, with no differences at 70 or 140 dpt. No differences were observed in outcome measures between wild-type (WT) CoO-TRIM mice and WT Saline controls. We report that CoO-TRIM can stimulate VEGF production and promote restoration of muscle structure and function when inflammation is present. Local injection of an inorganic biomaterial alone can benefit myopathic skeletal muscle.