MALDI IMS predict Whole-body of Mice response to Arecoline

Objectives: The objective of this study was to investigate the possible changes in protein profile due to the effects of arecoline during the late-stage pregnancy.
Methods: Mice in the last week of pregnancy (from day 14 of gestation) were exposed to arecoline (40mg/kg) or control normal saline solution (NS) via daily intraperitoneal injection for 2, 3, 4, 5, 6, or 7 days (that is group1, 2, 3, 4, 5, 6, respectively ). On the day before term, mice were euthanized and fetuses were delivered and rapidly frozen in hexane/dry ice. Proteomic analysis of the whole-body sections of mouse embryos was carried out by Matrix-assisted laser desorption ionisation imaging mass spectrometry (MALDI IMS).
Results: 1. Comparative analysis of acquired mass spectra of the two groups yielded 141 differential protein peaks in group 1, 133 differential protein peaks in group 2, 130 differential protein peaks in group 3, 125 differential protein peaks in group 4, 148 differential protein peaks in group 5, and 122 differential protein peaks in group 6 (p<0.01). All protein images were acquired on a MALDI-TOF MS in the linear mode.
2. Among the differential peaks, the best discriminatory m/z peaks in the mass rang m/z 700-4,000 were selected for protein identification, and most proteins identified were involved in rang m/z 700-100.
3. Organ-specific ion signals were reliably detected and many of the same proteins were also detected in multiple organs.
Conclusions: MALDI IMS can be used to detect proteins from organs present in a whole-body sagittal tissue section and reveal the molecular changes owing to side effects associated with arecoline from chewing areca nut during embryo development, providing deeper insight into the process of embryotoxicity.