Effects of ACTH4-10Pro8-Gly9-Pro10 on anti-inflammatory cytokine (IL-4, IL-10, IL-13) expression in acute spinal cord injury model (Sprague Dawley rats)

Background: Spinal cord injury (SCI) is a destructive neurological and pathological state that causes major motor, sensory and autonomic dysfunctions. It's final neurological outcome determined from both primary and secondary injury process. Neuroinflammation is a key component of the secondary injury mechanisms with local and systemic consequences. A neuroprotective compound, ACTH_4-10Pro⁸-Gly⁹-Pro¹⁰ also known as Semax has shown neuroprotective and anti-inflammatory properties. ACTH_4-10Pro⁸-Gly⁹-Pro¹⁰ also has actively used in the treatment of brain ischemia without serious complication reported. Here we analyzed the effects of ACTH_4-10Pro⁸-Gly⁹-Pro¹⁰ in regulating inflammatory cascade in SCI by looking at the expression of anti-inflammatory cytokine IL-4, IL-10, IL-13 in acute compression SCI.

Method: We do laminectomy in Sprague Dawley rats at the second thoracic vertebrae. After laminectomy we expose the myelum and create mild SCI model with 20gr and severe SCI with 35gr aneurysm clips. ACTH_4-10Pro⁸-Gly⁹-Pro¹⁰ was administered intranasally to the treatment group and 0,9% NaCl to the control group (placebo). Both group was remain alive and terminated at 3 and 6 hour. The preparations tissue sample were fixed in formalin and examined for immunohistochemistry. Quantitative measurement of anti-inflammatory cytokine (IL-4, IL-10, IL-13) was done in posterior horn with associated anti-monoclonal antibodies.

Result: Rats with mild SCI that were given ACTH_4-10Pro⁸-Gly⁹-Pro¹⁰ shown greater expression of IL-4, IL-10 and IL-13 at three hour post compression but only IL-10 and IL-13 elevated significantly at six hour. Rats with severe compression in ACTH_4-10Pro⁸-Gly⁹-Pro¹⁰ group shown greater expression of IL-10, IL-13 at three hour and IL-4, IL-10 at six hour compared with the placebo group.

Conclusion: Administration of ACTH_4-10Pro⁸-Gly⁹-Pro¹⁰ intranasal can increase anti inflammatory cytokine expression at Sprague Dawley rat model with mild and severe SCI. Expression of anti inflammatory cytokine was greater in mild compression and early hour (3 hour). Further research needs to be done to determine optimal dose and the actual clinical outcome in vivo.