Related Fluoxetine and Methylprednisolone Changes of TNF-α and IL-6 Expression in The Hypothyroidism Rat Model of Spinal Cord Injury

Spinal cord injury (SCI) is a serious clinical condition that leads to disability. Following primary injury, proinflammatory
cytokines play an important role in the subsequent secondary events. The thyroid hormone (TH) is known
as the modulator of inflammatory cytokines and acts as a neuroprotective agent. Methylprednisolone (MP) is used
for the early treatment of SCI. Fluoxetine (FLX), also is known as a selective serotonin reuptake inhibitor (SSRI), has
therapeutic potential in neurological disorders. The aim of the present study was to investigate the combined effects of
MP and FLX on SCI in the rat hypothyroidism (hypo) model.

In this experimental study, 48 male Wistar rats with hypothyroidism were randomly divided
into 6 groups (n=8/group): control (Hypo), Hypo+Surgical sham, Hypo+SCI, Hypo+SCI+MP, Hypo+SCI+FLX, and
Hypo+SCI+MP+FLX. SCI was created using an aneurysm clip and Hypothyroidism was induced by 6-Propyl-2-thiouracil
(PTU) at a dose of 10 mg/kg/day administered intraperitoneally. Following SCI induction, rats received MP and FLX
treatments via separate intraperitoneal injections at a dose of 30 and 10 mg/kg/day respectively on the surgery day
and FLX continued daily for 3 weeks. The expression levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6
(IL-6) were quantified by Real-time polymerase chain reaction (PCR) and Western blotting. Myelination and glutathione
(GSH) levels were analyzed by Luxol Fast Blue (LFB) staining and ELISA respectively.

Following combined MP and FLX treatments, the expression levels of TNF-α and IL-6 significantly decreased
and GSH level considerably increased in the trial animals.

Our results show the neuroprotective effects of MP and FLX with better results in Hypo+SCI+MP+FLX
group. Further study is required to identify the mechanisms involved.