Relationship between retinal protein kinase C and endothelin system in early diabetic rats / 中华眼底病杂志

ABSTRACT

Objective To investigate the alteration of protein kinase C (PKC) and endothelin system in early diabetic rats, and the effect of specific PKC inhibitor on the expression of retinal endothelin-1 (ET-1). Methods The rats model with streptozotocin(STZ)-induced diabetes were set up. The expression of retinal PKC was detected by enzyme-linked immunoabsorbent assay (ELISA). The expression of retinal ET-1, ET-3, ET-A and ET-B receptor mRNA was determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The alteration of retinal ET-1 mRNA after intravitreal injection of PKC inhibitor GF109203X in diabetic rats was also observed. Results The activities of membranous PKC were significantly increased in 2-week diabetic rats compared with that in normal rats(t=3.296, P=0 008), while activities of cytosolic PKC were unchangeable(t=0 138, P=0 894). The expression of retinal ET-1 mRNA was significantly increased(P=0 008), while no change was found in expression of ET-3, ET-A and ET-B mRNA(P=0 918,P=0 889,P=0 500). After intravitreal injection of 10 -5、10 -6、10 -7 mol/L PKC inhibitor GF109203X in diabetic rats, the expression of retinal ET-1 mRNA was decreased in a dose-dependent manner compared with the control rats. Conclusion Activation of PKC and increased expression of ET-1 could be found in the retina of early diabetic rats, and PKC inhibitor could inhibit the expression of retinal ET-1.