Effects of alpha-Lipoic Acid on Apoptotic Cell Death in Rat Hippocampus Following Transient Forebrain Ischemia-reperfusion Injury

PURPOSE: The purpose of this study was to evaluate effect of alpha-lipoic acid on apoptotic cell death in rat hippocampal neuron following transient forebrain ischemia-reperfusion (I/R) injury. METHODS: The four-vessel occlusion method was used to induce transient I/R injury in the forebrain of Sprague-Dawley rats. In the treatment group, alpha-Lipoic acid (LA) was administered subcutaneously at 50 mg/kg/day for 7 days before induction of I/R injury. RESULTS: Pretreatment with LA significantly reduced the number of TUNEL-positive neurons in the pyramidal cells layer of the hipocampal CA1 region 5 days after the ischemia, suggesting a marked reduction of apoptotic cell death. Pretreatment with LA also resulted in marked suppression at the transcript level of mRNA for caspase-3 at 24 hours, and decreased concentration of the active form of caspase-3 protein in the hippocampus at 1, 3, and 5 days after I/R injury. Furthermore, as indicated by western blot analysis, the concentration of apoptosis-inducing factor (AIF) in the hippocampus was reduced at 1 and 3 days after a transient I/R injury by pretreatment with LA. CONCLUSION: The results of this study suggest that LA has the potential to prevent neuronal cell death in the hippocampus by inhibiting intracellular signaling pathways responsible for apoptosis following transient I/R injury.

Mechanism of anti-apoptotic action of dipfluzine on neuronal damage of the rat hippocampal CA1 region subjected to transient forebrain ischemia / 药学学报

Aim To explore the relations between anti-apoptotic role of dipfluzine (DIP) and the death signaling transduction pathway initiated by CD95 molecules, and the transcription factor involved in the transcription regulation of CD95 molecules in the hippocampal CA1 region after transient forebrain ischemia. Methods The rat forebrain transient ischemia model was established through 15 min ischemia followed by 3 days reperfusion by using the four-vessel method. The rats were divided randomly into five groups: sham control group, ischemia / reperfusion (I/R) group, DIP treated groups (20, 40 and 80 mg·kg-1 body weight, ig, separately). Western blotting and RT-PCR were performed to detect the expression changes of Fas, FasL, caspase 10 p20, caspase 8, I-κB-α, and p-I-κB-α molecules in protein and mRNA levels, separately, and immunohistochemistry for molecular localization of Fas and FasL in rat hippocampus. Results The expression of Fas, FasL, and caspase 10 p20 in protein and mRNA levels increased after I/R, which was inhibited significantly after treatment with 20 and 40 mg·kg-1 of DIP (P<0.01). In 80 mg·kg-1 of DIP group, the expression of Fas and FasL protein was not significantly different from that of I/R group (P>0.05). The expression of caspase 8 and I-κB-α showed no significant differences in all groups (P>0.05), and no gene expression was observed for p-I-κB-α protein in the study. DIP significantly affected molecular distribution of Fas and FasL protein in CA1 subregion of hippocampus. Conclusion DIP inhibits the death signaling transduction pathway initiated by CD95 molecules in rat hippocampal CA1 subregion, and NF-κB transcription factor may not be involved in the transcription regulation of CD95 molecules after transient forebrain ischemia.