Regulated On Activation Normal T Expressed And Secreted And SPARC Expressed In Rejection Of The Corneal Allograft

Purpose: To evaluate the chemokines, RANTES and SPARC, gene expression after cornea transplantation and to determine whether there is temporal relation between chemokine expression and allograft rejection. This project may explore new methods for early diagnoses of cornea transplant rejection.Methods: First, The rat model of cornea transplantation and corneal alkali injury were established. Isografts and normal nonsurgical eyes served as control speciments. Secondly, both RATENS and SPARC gene expression by corneal epithelium of each experimental rat were evaluated . Total RNA was extracted from corneal epithelium , followed by the RT -PCR detection . The cDNA was semi-quantified by laser densitometry . Main products of RANTES and SPARC primer RT-PCR amplification were analyzed by restricted endonuclease digestion . Before above laboratory studies, experimental corneas were examined by slit-lamp and confocal microscopy through focusing(CMTF). Finally, cornea pathological data were used to confirm clinical diagnoses of cornea allograft rejection.Results: 1. There was no RANTES gene expression and minimal expression of SPARC in normal cornea epithelium; 2. Overexpression of RANTES gene by cornea epithelium was detected in rejected allograft eyes. RANTES was not detectable in isografts nor in corneal alkali injury groups; 3. Overexpression of SPARC was observed in cornea epithelium after cornea transplantation or corneal alkali injury. 4. In the case of allograft rejection, the tendency of overexpression in both RANTES and SPARC was correlated with positive findings of CMTF and pathology examination. 5. The change of RT-PCR results was earlier than the clinical findings by slit-lamp and CMTF techniques.Conclusion: Upregulation of RANTES mRNA expression by cornea epithelium is specifically associated with cornea allograft rejection. In contrast, increased expression of SPARC was observed in cornea allograft rejection , cornea chemical burn, and traumatic process. In terms of temporal sequence, the earliest detection of increased expression of both RANTES and SPARC preceded clinical phenomena of cornea allograft rejection about one week. Therefore, detection of mRNA profile of selected chemokines is useful method for early diagnosis of cornea allograft rejection , consequently...