A tannic acid doped hydrogel with small extracellular vesicles derived from mesenchymal stem cells promotes spinal cord repair by regulating reactive oxygen species microenvironment

Materials Today Bio, 2022 · DOI: https://doi.org/10.1016/j.mtbio.2022.100425 · Published: September 16, 2022

Simple Explanation

Spinal cord injury (SCI) often leads to permanent nerve damage due to inflammation and harmful molecules called reactive oxygen species (ROS). This study explores a new treatment using a special gel that releases tiny sacs from stem cells to help reduce inflammation and ROS. The gel, called sEVs-NGL/T, contains tannic acid for its antioxidant properties and releases small extracellular vesicles (sEVs) from mesenchymal stem cells, which have shown promise in reducing inflammation and promoting tissue repair. The results showed that this gel can protect nerve cells in lab tests and help rats with spinal cord injuries regain movement and preserve urinary function by reducing inflammation and ROS in the injured area.

Study Duration

56 days

Participants

24 Sprague–Dawley rats

Evidence Level

Not specified

Key Findings

1
The sEVs-NGL/T hydrogel exhibited excellent antioxidant properties in vitro, effectively scavenging DPPH radicals and reducing H2O2 levels.
2
In vivo, the sEVs-NGL/T hydrogel significantly improved motor function recovery in rats with SCI, as demonstrated by BBB scores, and reduced cystic cavitation in the injured spinal cord.
3
The hydrogel promoted nerve tissue regeneration, reduced oxidative stress (4-HNE and 8-OHdG expression), and inhibited the release of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in vivo.

Research Summary

This study introduces a novel sEVs-NGL/T hydrogel for treating spinal cord injury (SCI). The hydrogel combines tannic acid's antioxidant properties with the therapeutic potential of mesenchymal stem cell-derived small extracellular vesicles (sEVs). In vitro, the hydrogel demonstrated excellent antioxidant activity and protected nerve cells from oxidative stress. In vivo, it significantly improved motor function recovery, reduced tissue damage, and promoted nerve regeneration in a rat SCI model. The therapeutic effects are attributed to the hydrogel's ability to mitigate the ROS microenvironment and inhibit the release of pro-inflammatory cytokines, suggesting a promising strategy for SCI treatment.

Practical Implications

Potential Therapeutic Strategy

The sEVs-NGL/T hydrogel offers a promising therapeutic strategy for SCI by combining antioxidant and anti-inflammatory properties with the regenerative potential of MSC-derived sEVs.

Microenvironment Regulation

The study highlights the importance of regulating the pathological microenvironment, particularly ROS and inflammation, in promoting SCI repair.

Localized and Sustained Delivery

The hydrogel provides a vehicle for the localized, sustainable, and stable delivery of sEVs to the injured site, enhancing their therapeutic effects.

Study Limitations

1
Detailed molecular mechanisms underlying the positive effects of sEVs-NGL/T on SCI recovery are not fully elucidated.
2
The hydrogel is not injectable, potentially increasing surgical damage.
3
The release of sEVs from the hydrogel cannot be precisely controlled in vivo.

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