Role Of Protein Kinase C On The Expression Of Platelet-Derived Growth Factor And Endothelin-1 In The Retina Of Diabetic Rats

OBJECT: We applied STZ to induce diabetic rat model, and observed the expressions of PDGF-B and ET-1 during early diabetic retinopathy , to research the pathogenesis of diabetic retinopathy after treating by drugs and to provided certain theory for clinic. METHODS: Fifty male SD rats about 200g were divided into two parts :one part was for control group (10 rats),the other was for diabetic model making (40 rats).We applied STZ to induce the diabetic rat model and affirmed the rats without drug whose blood glucose was less than 5 mmol/l as the control group (C group) ,and affirmed the rats with polydipsia ,polyphagia , hyperdiuresis whose blood glucose was more than 16.9 mmol/l as diabetic rats. The diabetic rats were divided averagely into insulin group(INS group),LY333531 group(LY group) and diabetic group (D group). After one month, we determined the every group's expression of ET-1 and PDGF on mRNA level by RT-PCR, and determined the every group's expression of PDGF on protein level by Western blot, also analyzed the expression substance by semi-quantitation agarose gel electrophoresis;and determined the ET-1 consistence in blood plasm by direct radio-immunity. RESULTS:(1)The D group's expressions of PDGF-B and ET-1 on mRNA level were apparently higher than C group's(P<0.05);The ratios of IOD between PDGF-B,ET-1 and β-actin in D group were increased 1.32 -fold and 1.54 –fold compared with C group's. (2)The D group's expression of PDGF-B on protein level was apparently higher than C group's(P<0.05) , and the ratio of IOD was increased 1.55 -fold ;(3)The D group's of ET-1 consistency in blood plasm was apparently higher by 1.70 -fold than C group's(P<0.05) . There were no apparent difference of the PDGF-B and ET-1 on mRNA and protein level , by direct radio-immunity among INS, LY, C group . CONCLUSIONS:(1) In one month diabetic rat retina, there was obvious increase of PDGF-B and ET-1 expression on mRNA level ;(2) In one month diabetic rat retina, there was also obvious increase of PDGF-B expression on Protein level; (3) In one month diabetic rat blood plasm, there was obvious increase of ET-1 consistency; (4) Insulin and special PKC-βinhibitor can inhibit the expression of PDGF-B and ET-1;(5) PDGF-B could promote the expression of ET-1 in diabetic retina.