Amniotic fluid proteomic analysis of neural tube defects using surface enhanced laser desorption/ionization time-of-flight mass spectrometry

Abstract

Objective Using SELDI-TOF-MS technology to detect specific protein biomarkers in maternal anmiotic fluid of fetus with neural tube defects(NTDs)and pregnant rat amniotic fluid of fetal rat with NTDs. Methods Of the 20 maternal amniotic fluid samples obtained, 11 were from pregnant women with neural tube defects fetuses and 9 from healthy volunteers undergoing routine pregnancy μltrasonography examination. Amniotic fluid from five spina bifida, five anencephaly and one hydrencephaly pregnancies was retrieved by transabdominal amniocentesis. 45 female Wistar White rats were randomly assigned to deformity groups (n = 30) and control groups(n = 15). Pregnant Wistar rats in deformity groups were given a suspension of all-trans retinoic acid (40 mg/ml) and liquid paraffin and pregnant Wistar rats in control group were only given liquid paraffin on gestational days 10. About 0. 1 ml to 0. 3 ml Amniotic fluid of each pregnant rat was aspirated by a needle on gestational days 17. Eleven amniotic fluids of fetal rats with spina bifida and 15 normal controls were selected as experiment group for further SELDL Protein chip biosystem (PBS Ⅱ C) and CM10 chip were purchased from Ciphergen Biosystems (USA). The data were processed with the ProteinChip Software version 3. 1.1. Results A total of 35 qualified mass peaks (signal-to-noise ratio>5) were detected in maternal amniotic fluid between 1,000 and 30,000 Da. Compared with the spectra of control groups, there were 7 potential maternal amniotie fluid biomarkers detected in the spectra of the neural tube defects patients. The protein expression was high in 6 of 7 (rn/z 14 700, 7 995, 15 891, 16 027, 13 776, 11 040) and low in 1 of 7 (m/z 23 417). A total of 55 qualified mass peaks (signal-to-noise ratio>5) were detected in pregnant rat arnniotic fluid between 1,000 and 30,000. Compared with the spectra of control groups, there were 9 potential rat amniotic fluid biomarkers detected in the spectra of the neural tube defects rats. The protein expression was high in 5 of 9 (m/z 11 658, 27 387, 7 898, 11 603, 13 829) and low in 4 of 9 (m/z 5 124, 14 702, 5 403, 13 626). Compared those protein biomarkers between rat amniotic fluid and maternal amniotic fluid, five mass peaks, including 4 138(4 145), 7 947(7 941), 8 588(8 588), 9 385 (9 390), 14 702 (14 700), especially m/z 14 700 (P = 0.006) may be the same protein/ pep((de of them. Conclusions The biomarker proteins/peptides in maternal amniotic fluid of fetus with NTDs and pregnant rat amniotic fluid of fetal rat with NTDs were similar. This may be clinically useful in diagnosing NTDs. Key words: Neural tube defects; Surface enhanced laser desorption / ionization time-of-flight mass spectrometry; Amniotic fluid; Protein biomarker