Study on the promotion of spinal cord injury repair in rats by light-curing GelMA hydrogel combined with mitochondrial complex transplantation

doi:10.3877/cma.j.issn.2095-9141.2025.06.008

Abstract

Abstract:

Objective

To investigate the therapeutic efficacy and underlying mechanisms of methacryloyl gelatin (GelMA) hydrogel loaded with active mitochondria in promoting repair after spinal cord injury (SCI) in rats.

Methods

Sixty-three adult male SD rats (aged 8-10 weeks, SPF grade) were randomly assigned using a random number table into the Sham group (n=3), SCI group (n=15), SCI+GelMA group (hydrogel transplantation alone, n=15), SCI+Mito group (mitochondria transplantation alone, n=15), and SCI+GelMA+Mito group (combined hydrogel and mitochondria transplantation, n=15). The Sham group was only used for footprint analysis. A right-sided spinal cord hemisection injury model was established at the thoracic T10 level. According to the group assignment, corresponding materials were injected into the spinal cord lesion gap, followed by suturing of the overlying muscle and tissue. Prior to surgery, rheological characterization and scanning electron microscopy of the hydrogel were performed. At 24 h post-surgery, rats were euthanized, and tissue samples were collected to assess cell death by measuring Drp1 protein expression using Western blotting. At 7 d post-surgery, the expression of ARG1 was evaluated using Western blotting and immunofluorescence to assess inflammatory levels in the injured spinal cord region. At 28 d post-surgery, axonal regeneration was evaluated by detecting NF200 expression using Western blotting and immunofluorescence. From 7 to 28 d post-surgery, motor functional recovery of the hind limbs was assessed at multiple time points using the Basso-Beattie-Bresnahan locomotor rating scale and footprint analysis.

Results

At 24 h post-surgery, compared with the SCI group, SCI+GelMA group, and SCI+Mito group, the Drp1 expression level in the SCI+GelMA-Mito group was significantly lower, with statistically significant differences (P<0.05). At 7 d post-surgery, compared with the SCI group, SCI+GelMA group, and SCI+Mito group, the ARG1 fluorescence intensity and protein expression level in the SCI+GelMA-Mito group were significantly enhanced, and the differences were statistically significant (P<0.05). The footprint analysis experiment showed that compared with the SCI group and the SCI+GelMA group, the SCI+Mito group and the SCI+GelMA+Mito group had longer front and back step widths on the right hind limb, and narrower left and right step widths, with statistically significant differences (P<0.05). The BBB scores of the 4 groups of rats showed varying degrees of improvement over time at postoperative days 7, 14, 21, and 28, with SCI+GelMA+Mito group>SCI+Mito group>SCI+GelMA group>SCI group, and the differences were statistically significant (P<0.05).

Conclusions

GelMA hydrogel combined with mitochondrial transplantation has an obvious therapeutic effect on SCI, which can reduce cell death in the injured area, suppress inflammatory responses, promote axonal regeneration, and improve motor functional recovery. Therefore, this strategy may represent a feasible and promising therapeutic method for SCI in the future.

Key words: Mitochondrial transplantation, GelMA hydrogel, Spinal cord injury

Wenyong Gao, Can Tang, Youjie Yan, Min Wei, Hengzhu Zhang, Xiaodong Wang. Study on the promotion of spinal cord injury repair in rats by light-curing GelMA hydrogel combined with mitochondrial complex transplantation[J]. Chinese Journal of Neurotraumatic Surgery(Electronic Edition), 2025, 11(06): 380-389.

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Figures/Tables 5

Fig.1 Appearance-related characteristics of GelMA hydrogels

Fig.2 Drp1 expression levels in the spinal cord injury areas of 4 groups 24 h post-surgery

Fig.3 Immunofluorescence staining of M2 macrophages in the spinal cord injury areas of 4 groups at 7 d post-surgery

Fig.4 Immunofluorescence staining of MBP and NF200 in the spinal cord of 4 groups at 28 d post-surgery

Fig.5 Recovery of hindlimb motor function in four groups of rats after SCI

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