[Expressions of micro-calpain mRNA and protein in cerebral tissues of neonatal rats after hypoxic-ischemic brain damage].

OBJECTIVE: To identify the expression of micro-calpain mRNA and protein in cerebral tissues of neonatal rats after hypoxic-ischemic brain damage (HIBD) and its role in the pathogenesis of HIBD. METHODS: Seven-day-old Sprague-Dawley rats were randomly divided into seven groups: control group and groups with 0, 6, 12, 24, 48, and 72 hours of exposure to HIDB. Quantitative real-time fluroscent polymerase chain reaction and Western blot technique were employed to detect the expression of micro-calpain mRNA and its protein respectively. RESULTS: The micro-calpain mRNA in the ipsilateral cerebral tissues began to increase 6 hours after the HIDB and reached peak at 24 hours, and then gradually decreased but remained in a higher level than that of the control group until at 72 hours (P < 0.05). The activated micro-calpain protein started to increase 6-12 hours after the HIDB (P < 0.05) and reached peak at 24 hours (P < 0.01). Higher levels of micro-calpain protein were maintained until 48 and 72 hours after the HIBD (P < 0.05). CONCLUSION: The expressions of micro-calpain mRNA and protein increase with the HIBD. The micro-calpain may play a role in the pathogenesis of the HIBD.

[Alternations of ADF and G-actin in renal tubular epithelial cell of neonatal rats during kidney ischemic Injury].

OBJECTIVE: To study the changes of ADF and G-actin in renal tubular epithelial cell of neonatal rats during kindney ischemic injury. To explore the interactions between ADF and G-actin and their relationships with actin cytoskeleton. METHODS: Twenty-four neonatal rats were used to the experiments due to have the weights from 30 to 40 g respectively. Renal ischemia was induced by clamping the left renal pedicle for different periods of time that was in 10 min or 30 min. The kidneys of normal neonatal rats were functioned as the control group. Two kinds of primary antibodies, which one was rabbit anti-chick ADF antiserum and another was mouse monoclonal G-actin antibody, were used on one same section of kidney tissue. FITC-labeled and TRITC-labeled secondary antibodies were used to identify ADF and G-actin respectively. These samples were examined by using a fluorescene microscope. RESULTS: In control group, ADF and G-actin showed to be diffused in cytoplasm of renal tubular epithelial cell. In ischemic injury group, the distributions of ADF and G-actin were changed significantly to apical region of tubular epithelial cells and the renal tubula lumen. Regardless of the ADF expression to not change but G-actin was increased after kidney ischemia. CONCLUSION: Under the physiolgical condition, ADF and G-actin got a diffuse distribution in cytoplasm of renal tubular epitbelial cell. However, when the kidney got in ischemia, the distributions of ADF and G-actin were changed significantly to apica region of tubular epithelial cell or the renal tubular lumen.