AIM:To explore the effect of intravitreal injection FasL inhibitors on corneal apoptosis, Fas, FasL expression, Treg numbers in blood and lymph nodes and rejection index in rats after corneal transplantation.METHODS:A total of 24 SD rats(24 eyes)who received penetrating keratoplasty were randomly divided into two groups: PBS group received intravitreal injection of PBS(12 rats, 12 eyes)and FasL inhibitor group(12 rats, 12 eyes). Rejection index was recorded every week and blood samples and lymph node were collected at 1, 3 and 5wk after surgery to analyze the proportions of Treg. Corneal tissue was collected for detecting the expression of Fas and FasL and number of apoptosis.RESULTS: The expression of Fas, FasL in FasL inhibitor group decreased significantly compared with the PBS group(all P