Scolopendra subspinipes mutilans attenuates neuroinflammation in symptomatic hSOD1(G93A) mice

Abstract

Background: Amyotrophic lateral sclerosis (ALS) is a progressive, adult-onset neurodegenerative disorder characterized by selective motor neuron death in the spinal cord, brainstem, and motor cortex. Neuroinflammation is one of several pathological causes of degenerating motor neurons and is induced by activated microglial cells and astrocytes in ALS.Scolopendra subspinipes mutilans (SSM) is utilized in traditional Chinese and Korean medicine for the treatment of a variety of diseases, such as cancer, apoplexy, and epilepsy. However, the mechanisms underlying the effects of SSM are currently unclear, even though SSM increases immune and antibiotic activity.

Methods: To determine the effects of SSM on symptomatic hSOD1G93A transgenic mice, SSM (2.5 μℓ/g) was injected bilaterally at the Zusanli (ST36) acupoint three times per week for two weeks. The effects of SSM treatment on anti-neuroinflammation in the brainstem and spinal cord of hSOD1G93A mice were assessed via Nissl and Fluoro-Jade B (FJB) staining, and immunohistochemistry using Iba-1, CD14, HO1, and NQO1 proteins was evaluated by Western blotting.

Results: In this study, we investigated whether SSM affects neuroinflammation in the spinal cord of symptomatic hSOD1G93A transgenic mice. We found that SSM treatment attenuated the loss of motor neurons and reduced the activation of microglial cells and astrocytes. Furthermore, we demonstrated that SSM administration in this animal model of ALS suppressed oxidative stress in the brainstem and spinal cord by 1.6- and 1.8-fold, respectively.

Conclusions: Our findings suggest that SSM, which has previously been used in complementary and alternative medicine (CAM), might also be considered as an anti-neuroinflammatory therapy for neurodegenerative diseases.

Figure 1

SSM treatment increases motor neuron survival in hSOD1^G93A mice. SSM (2.5 μℓ/g) was administered bilaterally at acupoint ST36 three times per week for two weeks. Photomicrographs of Nissl (A) and FJB (C) staining of the lumbar spinal cord. Each right-hand column depicts a magnified image of the rectangular region of the corresponding image in the left column. The numbers of viable motor neurons (B) and degenerating FJB-positive glial cells (D) were counted, as described in the magnified spinal cord column. (E) Photomicrographs of MAP2 staining of the lumbar spinal cord. Each right-hand column depicts a magnified image of the rectangular region of the corresponding image in the left column. (F) Quantitative analysis of MAP2-positive cells each magnified column. Control (Sal) animals were bilaterally injected with an equivalent volume of saline at the ST36 acupoint. The data are presented as the means ± SEM (N = 6 animals/genotype). Statistical significance was assessed via t-test. ***P < 0.001 compared to the saline-treated group. Magnification: 100×. Bar = 500 μm. Sal: saline-treated hSOD1^G93A mice, SSM: Scolopendra subspinipes mutilans (SSM)-treated hSOD1^G93A mice.

Figure 2

SSM treatment reduces the expression of Iba-1 and GFAP in 113-day-old hSOD1^G93A mice. Representative photomicrographs of Iba-1 (A) and GFAP (B) staining in the lumbar spinal cord. Each column on the right depicts a magnified image of the rectangular region of the corresponding image in the left column. (C) Representative Western blot showing the activation of microglia using an Iba-1 antibody and the detection of astrocytes with a GFAP antibody in the brainstems and spinal cords of hSOD1^G93A mice. (D) Quantitative analysis of the levels of Iba1/tubulin and GFAP/tubulin, respectively. The data are presented as the means ± SEM (N = 6 animals/genotype). Statistical significance was assessed via t-test. **P < 0.01 compared to the saline-treated group. SSM: Scolopendra subspinipes mutilans, BS: brainstem, SP: spinal cord.

Figure 3

SSM treatment regulates the expression of CD14, HO1, and NQO1 in the brainstems and spinal cords of hSOD1^G93A mice. (A) Representative Western blot showing the expression of CD14, HO1, and NQO1 in the brainstem and spinal cord following the administration of SSM. (B) Quantification of the level of CD14/tubulin, HO1/tubulin, and NQO1/tubulin. The data are presented as the means ± SEM (N = 4 animals/genotype). Statistical significance was assessed via t-test. ***P < 0.001, **P < 0.01, and *P < 0.05 compared to the non-treated group. BS: brainstem, SP: spinal cord.