BACKGROUND: Intercellular adhesion molecule-5 (ICAM-5) relieves the damage of beta-amyloid protein to PAJU cells. However, little is known about how ICAM-5 works as a neurotrophic factor, or whether ICAM-5 lessens neuronal damage under ischemic conditions following cerebral infarction. OBJECTIVE: To investigate the effects of ICAM-5 on PAJU cells growth in serum-free medium under ischemic conditions following cerebral infarction. DESIGN, TIME AND SETTING: The cytological in vitro study was performed at the Central Laboratory, Second Xiangya Hospital, Central South University, China, in June 2009. MATERIALS: Human ICAM-5 gene transfected into PAJU-TLN cells was supplied by the Life Science College, Helsinki University, Finland. Empty vector transfected PAJU-NEO cells were established by the Gene Center, Second Xiangya Hospital, Central South University, China. METHODS: PAJU-TLN cells transfected with human ICAM-5 or empty vector were incubated in serum-free medium. MAIN OUTCOME MEASURES: Phase contrast microscopy was used to observe changes in PAJU cell morphology. 3-(4, 5-dimethylthiazolzyl)-2, 5-diphenyltetrazolium bromide was used to determine cell viability. Hoechst 33258 was used to stain cell nuclei. Flow cytometry was utilized to measure the apoptosis rate of both PAJU-TLN and PAJU-NEO cells. RESULTS: Both PAJU-TLN and PAJU-NEO cells were injured by cultivating in serum-free medium, but the survival rate of PAJU-TLN cells was significantly higher. CONCLUSION: ICAM-5 protects PAJU-TLN cells from serum deprivation-induced apoptosis, induces the outgrowth of PAJU cells, and diminishes their morphologic impairment. However, little is known about how ICAM-5 works as a neurotrophic factor, or whether ICAM-5 lessens neuronal damage under ischemic (ICAM-5) relieves the damage of beta-amyloid protein to PAJU cells. conditions following cerebral infarction. OBJECTIVE: To investigate the effects of ICAM-5 on PAJU cells growth in serum-free medium under ischemic conditions following cerebral infarction. DESIGN, TIME AND SETTING: The cytological in vitro study was performed at the Central Laboratory, Second Xiangya Hospital, Central South University, China, in June 2009. MATERIALS: Human ICAM-5 gene transfected into PAJU-TLN cells was supplied by the Life Science College, Helsinki University, Finland. Empty vector transfected PAJU-NEO cells were established by the METHODS Center: Second Xiangya Hospital, Central South University, China. METHODS: PAJU-TLN cells transfected with human ICAM-5 or empty vector were incubated in serum-free medium. MAIN OUTCOME MEASURES : Phase contrast microscopy was used to observe changes in PAJU cell morphology. 3- (4, 5-dimethylthiazolzyl) -2, 5-diphenyltetrazolium bromide was used to determine cell viability. Hoechst 33258 was used to stain cell nuclei. RESULTS: Both PAJU-TLN and PAJU-NEO cells were injured by cultivating in serum-free medium, but the survival rate of PAJU-TLN cells was significantly higher. CONCLUSION: ICAM-5 protects PAJU-TLN cells from serum deprivation-induced apoptosis, induces the outgrowth of PAJU cells, and diminishes their morphologic impairment.