Autophagic effect of programmed cell death 5 (PDCD5) after focal cerebral ischemic reperfusion injury in rats

- PDCD5 is involved in both apoptotic and autophagic-type programmed cell death.
- PDCD5 siRNA reduced the ratio of LC3 II/I and the expression of Beclin 1.
- PDCD5 siRNA reduced apoptotic and autophagic cell death, improved behavior and mortality.

Former studies indicated that programmed cell death 5 (PDCD5) protein could accelerate the process of apoptosis in response to some stimuli in various kinds of cells via the intrinsic or extrinsic pathway. In this study, we aimed to demonstrate for the first time that protein level of PDCD5 are related to autophagic activity after focal ischemic brain injury in rats. One hundred and twenty-five Sprague-Dawley rats (male) were randomly divided into the following groups: Sham operated, Middle Cerebral Artery Occlusion/Reperfusion (MCAO), MCAO + Control siRNA and MCAO + PDCD5 siRNA. Outcome measurements include neurobehavioral outcomes, brain infarct volume, brain water content, BBB disruption, MRI and double fluorescence labeling. Western blot and histopathophysiological techniques were used to measure the expression of PDCD5 and some pro-autophagic proteins such as Beclin 1 and the LC3-II/LC3-I ratio. The study found that decreased PDCD5 expression via intracerebroventricular injection of PDCD5 siRNA significantly improved the neurobehavioral outcome, reduced the infarct ratio, cerebral edema and BBB disruption. These results were associated with decreased expression of Beclin 1 and the LC3-II/LC3-I ratio in the penumbra area. Rapamycin, an inducer of autophagy, partially weakened the effect of PDCD5 siRNA. In conclusion, this study suggested that PDCD5 was a key regulator of autophagy that might play an important role following MCAO injury.