Pre-B-cell colony-enhancing factor as a target for protecting against apoptotic neuronal death and mitochondrial damage in ischemia

Focal ischemic stroke（FIS）results from the lack of blood flow in a particular region of the brain and accounts for about 80%of all human strokes.Although tremendous efforts have been made in translational research,the treatment strategies are still limited.Tissue plasminogen activator is the only FDA-approved drug currently available for acute stroke treatment,

Stereotaxic microinjection of adenovirus-mediated human tissue Kallikrein gene reduces apoptosis in a rat model of middle cerebral artery occlusion

BACKGROUND：Several studies have demonstrated that Kallikrein gene transfer provides neuroprotection. Whether the neuroprotective effects of human tissue Kallikrein （HTK） are associated with apoptosis remains unclear. OBJECTIVE： To investigate the effects of HTK on apoptosis in the peripheral cerebral infarct region. DESIGN, TIME AND SETTING： The completely randomized grouping, gene engineered, controlled experiment was performed at the Lin Baixin Laboratory Center, the Second Affiliated Hospital of Sun Yat-sun University between September 2007 and April 2008. MATERIALS： Ninety clean, healthy, male, Sprague Dawley rats were included. pUC19-HTK plasmid was constructed in the Laboratory for Neurology, the Second Affiliated Hospital of Sun Yat-sen University, China. bcl-2, bax, caspase-3, and β-actin were designed and purified by Shanghai Shuiyuan Company, China. METHODS： Middle cerebral artery occlusion （MCAO） model was established in all rats. At 72 hours after MCAO model establishment, rats were randomly divided into 3 groups, with 30 rats per group： blank control, saline, and pAdCMV-HTK. The saline and pAdCMV-HTK groups were respectively stereotactically micro-injected with 5 μL physiological saline or pAdCMV-HTK at the area surrounding the cerebral infarction region. Only puncture was performed, without any injection, in the blank control group. MAIN OUTCOME MEASURES： At 72 hours after MCAO establishment, as well as at 24 hours, 72 hours, and 7 days subsequent to treatment, exogenous HTK expression was detected by immunohistochemistry. Apoptosis was examined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL）, while mRNA levels of bcl-2, bax, and caspase-3 were detected by reverse transcription-polymerase chain reaction. In addition, neurological severity scores were evaluated prior to and after treatments. RESULTS： Ninety rats were included in the final analysis. HTK was primarily detected in the cytoplasm at 24 hours after pAdCMV-HTK injection. Thereafter, HTK expression gradually increased and reached a peak level at 72 hours after injection, which was significantly different from the blank control and saline groups （P 〈 0.05）. At 7 days, HTK expression began to decrease, but remained higher than the saline and blank control groups （P 〈 0.05）. Apoptotic cells aggregated around the cerebral infarction region. Compared with the saline and blank control groups, the mean number of TUNEL-positive cells was notably decreased in the pAdCMV-HTK group at each time point after treatment （P 〈 0.05）. mRNA levels of bcl-2, bax, and caspase-3 were elevated in all groups at 24 hours after treatment, peaked at 72 hours, and then gradually decreased again at 7 days. Compared with the saline and blank control groups, bcl-2 slightly increased, but was not significantly different from the pAdCMV-HTK group （P 〉 0.05）. bax and caspase-3 mRNA levels were significantly reduced at 24 and 72 hours after treatment （P 〈 0.05）. At 72 hours and, in particular, at 7 days after treatment, neurological severity scores were significantly less in the pAdCMV-HTK group compared with the saline and blank control groups （P 〈 0.05–0.01）. CONCLUSION： HTK could protect neural cells in the peripheral cerebral infarction region from apoptosis, which resulted in a better outcome. This may be related to modulated bcl-2 expression and reduced bax and caspase-3 expression.