Exploration of tongue coating protein based on proteomics assessment and bioinformatics analysis

Objective: To observe the coating of tongue to identify the diagnosis and explore its mechanisms at molecular level by using proteomics techniques. Method: Subjects were divided into four groups: normal thin and whitish coating group, patho-thin coating group, thick coating group and exfoliative coating group according to the presentation of the coating of tongue and with or without system organic diseases; two-dimension electrophoresis was conducted with immobilized pH gradients as first-dimension and vertical SDS-PAGES as second dimension. Proteins expressional signal were examined by sliver staining and image analysis of ImageMaster 2D Platinum software. Proteins altered in expressional level were digested by trypsin. The peptide mass fingerprint was identified by MALDI-TOF MS/MS. Result: The results of protein spots in these four groups were 1082plusmn105, 1052plusmn85, 1129plusmn98 and 1143plusmn140 respectively. According to the analysis of those selective protein spots by mass spectrometry and bioinformatics studies, 13 proteins closely related to tongue coating had been found, among which cystatin B, cytokeratin 13 and GAL7 protein were found for first time, which were closely related to the changes of tongue coating. Furthermore, there were 5 new proteins identified, which have not been recorded in the international Protein Data Bank till today, of which the biological effect needs to be further explored. Conclusion: The research method for tongue coating on the basis of proteomics and bioinformatics was feasible. The protein profile present significantly difference between patho-tongue coating and normal tongue coating. Deep research on proteomics of tongue coating may hopefully become the scientific proof and microcosmic index of clinic diagnosis of traditional Chinese medicine, evaluation of herbal pharmaceutical effect, method for screening new drugs and exploring their pharmacodynamics.