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The effect of the novel immunosuppressant FTY720 on inflammatory response in brain tissue of rats with brain injury

Jian-Yong Cai, Xiao-Qiao Dong, Qun Lin, Hua-Jun Ba, Chuan Lu, Mao-Hua Chen, Jun Sun

Objective: To observe the effect of the novel immunosuppressant FTY720 on inflammatory response in brain tissue of rats with brain injury and to explore its related mechanism.

Methods: 60 Wistar rats were randomly divided into control group, sham-operated group, model group and treatment group with 15 in each group. Wherein the sham-operated group were only drilled to the bone without fluid-percussion. Feeney method was used in the model group to set up severe brain injury of rat models. Former the treatment group model established in 0.5 h, FTY720 (1 mg/kg) were administrated by intraperitoneal injection. Then the cerebral cortex of rats was HE-stained to observe the inflammation response. TNF-α (TNF-alpha), IL-1β (Interleukin-1β), and IL-6 (Interleukin-6) levels in tissue were determined with ELISA assay; Immunohistochemical was used to detect the OX-42 expression of microglia; Pro-caspase 3, pro-caspase 9, and NF-κB p65 subunit levels in the nucleus were measured by western-blotting; TUNEL (transferase-mediated deoxyuridine triphosphate-biotin nick end labelling) assay was applied to inspect apoptosis of neuronal cells.

Results: HE staining showed the rat brain cortex of the control group and the sham-operated group were normal, but rats in the model group exhibited significant brain haemorrhage, and alleviated haemorrhagic symptoms were discovered in FTY720 treatment group. Compared with the normal group and the sham-operated group, IL-1β, IL-6 and TNF-α, the pro-inflammatory cytokines, displayed increased secretion in the model group. Following FTY720 treatment, cytokines above were significantly reduced, but no obvious effect on the expression of OX-42. Pro-caspase 3, pro-caspase 9 and p65 in the nucleus were expressed upward after brain injury, whereas the three proteins decreased with FTY720 treatment. Cell apoptosis was significantly increased following with brain injury in rats, while FTY720 could ameliorate the apoptosis.

Conclusions: FTY720 plays a protective role on brain injury in rats through the potential mechanism of inflammation and apoptosis inhibition.