Proteomic analysis of down-regulated proteins in colonic mucosa of chronic slow transit constipation rats

Objective： To investigate the alternations of proteins in the colonic mucosa of chronic slow transit constipation （STC） rats with a 2-DE-based proteomic method and analyze the function of these down-regulated proteins so as to provide theoretical basis for the pathogenesis of intestinal mucosa of chronic STC rats. Methods： STC model was established by feeding rats with 8 mg/（kg＇d） diphenoxylate for 120 d. An experimental model of chronic STC rat was used for separation of proteomics from colonic mucosa using two-dimensional electrophoresis （2-DE）. Proteins altered in expressional level were identified by Image Master 2DElite, mass spectrometry, and bibliometrics were applied to identify the differential protein expression and their clinical s observed in the pathogenesis lgn of ificance and function were analyzed. Results： Obvious differential protein expression was STC, including mast cell protease （A1）, non-specific dipeptidase （A2） and chondrosome succinate dehydrogenase precursor （A3）. The expressions of A1, A2 and A3 were down-regulated in the gel graph of STC rats Conclusion： The down-regulation of chondrosome succinate dehydrogenase, mast cell protease as well as non-specific dipeptidase in rat colon suggests the functional impairment of the oxidoreduction of mitochondrion is very important in the genesis and development of STC. The immunological reaction of STC rats is weakened, and the function of digesting and absorbing protein may be damaged to some extent.

EFFECT OF A 30 kD PROTEIN FROM TECTAL EXTRACT OF RAT ON CUL-TURED RETINAL NEURON

For the first time we have shown here that the constituent from tectal extract (Te) which can support and promote the survival and growth of the retinal ganglion cell is a 30 kD protein. (i) Using MTT colorimetric microassay to measure the optical density for the survival and growth of the cultured retinal neuron, it was found that the optical densities for the experimental cultures with either Te, or its 10-30 kD fraction, or its ≥30 kD fraction were 2-4 times that of the control culture without Te (P<0.01). This indicated that experimental cultures were more active in growth, (ii) The retinal neurons cultured on Te Phast gels showed that large retinal neurons (>18 μm) grew only on the gel region containing the 30 kD protein. The retrograde prelabelled with horseradish peroxidase (HRP) for retinal ganglion cells indicated that these surviving neurons grown on Te Phast gel were HRP positive, i.e. retinal ganglion cells, (iii) The retinal explants cultured with 30 kD gels at a close distance of 1 mm apart revealed that many neurite outgrowths, up to 400 μm, extended from the retinal explants towards 30 kD gels, and that many individual cells and tissue masses migrated out from the explants and grew onto 30 kD gels. They were stained anti-neuron specific enolase and anti-Thy 1.1 positive, indicating they are retinal ganglion cells. Therefore, we concluded that the 30 kD protein is the neuronotrophic factor in the tectal extract specific for retinal ganglion cells.