Expression Of β-APP And MAP-2 After Cerebral Contusion Of Rat

Objective:To examine the expression trend ofβ-APP and MAP-2 in the brain after cerebral contusion of rat by immunohistochemical SABC,westerbloting and real-time fluorescent quantitative RT-PCR, In order to explore the application for estimating the early time of brain contusion in forensic medicine aspect.Methods:The rat model of cerebral contusion was founded Feeney s method.The 64 SD rats were divided into control group (contain 8 rats) and experimental group (contain 56 rats) randomly. Experimental group were divided into7 subgroup by dating of wound.The cerebral contusion was performed on the side of middle of skull of experimental animal by using a gravitational force of a free falling weight. Tissue samples were fixed;paraffin embedded,sectioned and then stained by H.E performed to identify the pathologic change ofβ-APP and MAP-2 at different internals within 14 days after brain injury. The brain tissue of 100mg were cut respectively at 1h,4h,12h,48h,72h,7d,14d (8rats in each subgroup) and then the samples were stored in liquid nitrogen. Rats in control group were dealt as same as rats in experimental group except for gravitational force. To examine the expression trend of P-APP and MAP-2 in the brain after cerebral contusion of rat by immunohistochemical SABC westerbloting and real-time fluorescent quantitative RT-PCR, analyzed by use of the computer image analysis technology, Contrast with uninjured group.The results were assessed by statistic analysis.Results:(1) The expression ofβ-APP could be detected at 1h after injury, increased at 4h and peaked at 12h.Positive cells decreased with the prolongation of injury time. Little expression was found at 7d but still higher than the control. Return to the level of control at 14 d.(2) The expression of MAP-2 lost obviously at 1h and peaked at 4h, Positive cells increased with the prolongation of soon afterwards injury time.Conclusion:The time-dependent expression ofβ-APP and MAP-2 in the brain tissue after cerebral contusion of rat could be applied in dating of wound for braincontusion.Immunoemical is simple and convenient.Real-time fluorescent quantitative RT-PCR is accurate and sensitive and refer to forensic study.