Effect Of MDMA On Oxidative Stress,Proteins Related With Apoptosis And Endoplasmic Reticulum Ca²⁺ Channel In Rat Brain For24Hours

[Objectives]3,4-Methylenedioxymethamphetamine (MDMA, also known as "ecstasy") is a ring-substituted phenylamine with very high abuse liability around the world. Many medico legists and toxicologists made researches on its mechanism of the toxicity. However, almost all of these studies were focus on the causes of the changes after abuse of MDMA24hours later. Whether does abuse of MDMA have any effects on organism within the first day? Little is understood about it. Some preclinical and clinical evidences show MDMA can made some users excited and leads to neurotoxic effects on central neurons only within a few minutes. For this reason, it is very necessary to study the changes on central nervous system for the first24hours after the consumption of MDMA. In order to find out the nervous effects within the first24hours, the subject made research on three probable aspects (oxidative stress, apoptosis and endoplasmic reticulum Ca2+channel) on brain tissue in rats.[Methods] Part1:1. An experiment model of forensic toxicology was set up under in vivo adult animal conditions, for administration of MDMA20mg/kg into abdominal cavity.32SD rats were supposed to be divided into experimental group(27rats) and control group(5rats). Then, all the rats in experimental group were consumed to be killed in three groups:1h,12h and24h after using MDMA.9rats in the1h group were executed. However,6rats died spontaneously during2-6h after injection of MDMA, which was named as spontaneous death group. The remaining rats were randomly divided into12h group(6rats) and24h group(6rats). The brain tissues of each group rats were taken out to reserve.2. To analyze of5-HT and DA in three groups and spontaneous death group by High Performance Liquid Chromatography (HPLC).3. To measure the activity of MDA in different groups by the method of TBA; to measure the activity of SOD by Hydroxylamine method. Part2:1.1h group,12h group,24h group and contral group are the same as the part1.2. To present rats’ brain cells by HE and TUNNEL staining; to analyze of the proteins about apoptosis:bcl-2, bax and caspase-3by Western Blot and immumohistochemical staining. Part3:1. To administration of drugs and to make groups as same as the part2.2. To analyze the expression of Ryr2and SERCA2by the method of RT-PCR and immumohistochemical staining.[Results] Part1:1. Obvious toxic reactions were observed after administration of MDMA, and there was spontaneous death of rats in6hours with the mortality rate was22.22%.2. MDMA administration produced significant decreases in only5-HT tissue content in each group, while there were significant grows in DA content in both24h group and spontaneous death group.3. There were increases of SOD in1h and24h group comparing to the control group, while decline in spontaneous death group. Part2:There was no significant difference in the number of apoptotic cells in each exposed group, while MDMA administration led to the bcl-2/bax ratio rising and caspase-3falling. Part3:1. The analysis of Ryr2was1h group had no obvious change, but the contents in12h and24h groups increased significantly after MDMA abusing.2. The expression of SERCA2was higher in exposed groups than control group.3. The contents about expression and mRNA of Ryr2and SERCA2were increasing with time.[Conclusions]1. Disposable20mg/kg MDMA administration in rats can lead to the neurotoxicity on monoamine terminals and oxidative stress reaction in brain within24hours. Serious damages caused by MDMA maybe fatal.2. MDMA administration produces the raising of antioxidative enzymes SOD and the effect of resistance to apoptosis.3. MDMA administration can induce the expression of Ryr2and SERCA2who are endoplasmic reticulum Ca2+channel proteins.4. Sublethal injury by MDMA can provide some protections on brain tissue. The mechanism of nervous protections is related with antioxidative enzymes SOD, anti-apoptotic protein Bcl-2and endoplasmic reticulum of Ca2+channel proteins.