国家自然科学基金项目30371535;广东省自然科学基金项目32874:广东省科技计划项目A1080201;广东省医学科研基金项目 National Nature Seience Foundation of ChinaNo.3037 1535:Nature Science Foundation of Guangdong ProvinceNo.32874:Technology Project of Guangdong ProvinceNo.A1080201;Medical Seientifie Research Foundation of GuangdongProvince2004382