Roles Of FKBP12.6 In Brain Ischemia Injury Of Mice And Effects Of CDC42-deficiency On Food Intake In Mice

Objective: FKBP12.6, also called the FK506 binding protein 12.6, is a kind of protein with the size of 12.6 KD, which can be combined with immunosuppressant FK506. The protein can selectively bind to the Ca2+ channel of Ry R2 in the sarcoplasmic reticulum of cardiomyocytes with the function of keeping the Ry R2 steadily in the closed state, indicating that it plays an important role in the stability of intracellular Ca2+ balance. Cerebral ischemia is a kind of the strokes, which is a common cardio-cerebrovascular disease. In the process of cerebral ischemia injury,the increases abnormally of intracellular Ca2+ is one of the important mechanisms of the cerebral ischemia injury. As FKBP12.6 plays an important role in the stability of intracellular Ca2+balance, it probably has an important effect on the cerebral ischemia.CDC42 is also called the cell division cycle protein 42, mainly involved in the depolymerization of cytoskeleton proteins and it is closely related to cell morphology,migration and split. It has been reported that Rat Insulin-2 Promoter drives Cre(Rip-Cre) expression specific CDC42 knockout mice also showed the phenotypes of disruption of some brain nuclei such as arcuate nucleus. Arcuate nucleus is the centers of accommodation of feeding and energy metabolism balance. Accordingly,we preposed that there may be a dysfunction of metabolism which invovled in the brain of the Rip-Cre specific CDC42 knockout mice. Therefore, in the present study,we will investigate the roles of FKBP12.6 in cerebral ischemia injury of mice and also the effects of CDC42-deficiency on food intake in the Rip-Cre specific knockout mice.Methods: The modeling of middle cerebral artery occlusion, pull out the thread again to fill after 60 minutes of ischemia, cut the brain into 1 mm thick slices for TTC staining, and figure out the nerve damage of the area of the ischemia. The group of give-FK506 will be given an abdomen injection of 10mg/kg 45 minutes before the ischemia. The control group will be given 10ml/kg normal saline. Cultivate the cerebral cortex cells of the fetal rat. Then have an Oxygen glucose deprivation(OGD)processing, the processing time is 1.5 hours and 3houts. The control group doesn’t do anything. Cultivate them for 24 hours and the hoechest staining will tell the number of dead cells and evaluate the nerve injuries. The the Rip-Cre specific CDC42 knockout mice and the control group will be fast for 24 hours and then monitor the food intake after 0.5h, 1h, 2h, 4h, 8h, 12 h, 24 h. A week later, monitor the food intake every day of them in normal situation and last for seven days. The HE staining frozen section of the coronal brain showed the morphology of Neuronal cell and the structure of brain to analyse the effect of CDC42 conditional knockout to the food intake.Results: 1. The disruption of FKBP12.6 gene does not protect the brain from the ischemic injury compared with control mice in vivo. 2. The apoptosis of cerebral cortex nerve cells from FKBP12.6 knock out mice have no significant difference with control group after OGD-R treatment in vitro. 3. There is an obvious protection in cultural nernone from both FKBP12.6 knockout mice and control mice with treatment of FK506 in vitro. 4. The body weight and food intake of the Rip-Cre specific CDC42 knockout mice are significant lower than the control group. 5. The region of third ventricle in the brain of the Rip-Cre specific CDC42 knockout mice is obviously reduced.Conclusions: 1. We demostrated that the knockout of FKBP12.6 gene had no significant effects on cerebral ischemia injury both in vivo and in vitro experiments,and the disruption of FKBP12.6 gene did not affect the the nerve protective role of FK506. 2. There were significant changes in functions and morphology such as the decrases of food intake and body weight, the reduction of the region of third ventricle in Rip-Cre specific CDC42 knockout mice.