The Effects Of Lipid And High Glucose On Diabetic Retinopathy And The Expressions Of NO, NOS And PDGF-B Of Retinal Endothelial Cells

Part 1. The effects of high fat diet ingestion on the pathologic change of DR in streptozotocin-induced diabetic ratsObjective: To investigate the effects of high fat diet ingestion on the pathologic change of DR in streptozotocin-induced diabetic rats.Methods: Diabetes was induced in 40 rats with a single intraperitoneal injection of streptozotocin (STZ). Experimental rats were divided into A(non-diabetic rats on normal fat diet) ,B(non-diabetic rats on high fat diet) ,C (diabetic rats on normal fat diet) and D(diabetic rats on high fat diet) groups. The morphology of retinal paraffin slide,digest preparation and ultrastrucure were observed by light microscope and transmission electronmicroscope.Results: Retinal digest preparation: There was no abnormal morphologic change in A and B group. Acellular capillaries were seen occasionally and the number of pericytes was decreased slightly in C group. The severest morphologic change of capillary was seen in D group, including more acellular capillaries, less pericytes and loss irrigation of capillary. HE stain slide: There was no abnormal morphologic change in A and B group. Thickening retina was found in C group,especially inner plexiform layer, rod cell and cone cell layer. The severest lesion was seen in C group, including disorder of cell structure, intern granulose layer edema, decrease of ganglionices number, retinal venae expansion, exuding and hemorrhage. Transmission electronmicroscope: There was no abnormal ultrastructure change in A and B group. Edema endothelial cells and pericytes and thickening basement membrane were observed in C group. Marginal heterochromatin in endothelium and pericyte ,edema and degeneration of mitochondrion , stricture of capillary cavity , disorder of the ultrastructure of discus membrane of external fragment and edema of mitochondrion of internal fragment of optic cell were found in D group.Conclusion: High fat diet ingestion inducing hyperlipoidemia can promote the development of DR in diabetic rats.Part 2. Lipid and glucose participate in the pathogenesis of DRChapter 1. The effects of LPC and glucose on the expressions of NO and NOS in bovine retinal microvascular endothelial cellsObjective: To study the effects of LPC and glucose on the expressions of NO and NOS in cultured bovine retinal microvascular endothelial cells(BRECs).Methods: The primary BRECs were cultured by different selective media and were pured by differential conglutination. The primary BRECs were divided into 3 groups:the first group was exposed to a range of LPC concentration (0-60umol/L);the second group was exposed to different glucose concentration (5.6,30mmol/L)and mannitol concentration(20 mmol/L);the third group was exposed to LPC concentration (60umol/L) and glucose concentration (30mmol/L). The NO content and NOS activity in conditioned media of BRECs were assessed by NO and NOS kits. The levels of eNOS mRNA were determined by RT-PCR analysis.Results:â‘ The NO content, NOS activity and the levels of eNOS mRNA of BRECs were lower at LPC concentration 60umol/L compared to control after 24 hours (p<0.05).â‘¡The NO content, NOS activity and the levels of eNOS mRNA of BRECs decreased at glucose cencontration 30mmol/L after 24 hours compared to 6 hours(p<0.01). Mannitol concentration 20mmol/L of osmotic pressure equivalent with glucose concentration 30mmol/L has no effect on the NO content and NOS activity(P>0.05).â‘¢The NO content, NOS activity and the levels of eNOS mRNA of BRECs were significantly lower at LPC concentration 60umol/L and glucose concentration 30mmol/L compared to control after 24 hours.Conclusion: These results demonstrate that LPC and glucose may decrease the expression of NO and NOS in BRECs, and with the synergistic effect of the two factors. These may be one of the pathogenesis of dyslipidemia participating in the development of DR.Chapter 2. The effects of LPC and glucose on the expressions of PDGF-B in bovine retinal microvascular endothelial cellsObjective: To study the effects of LPC and glucose on the expressions of PDGF-B in cultured bovine retinal microvascular endothelial cells(BRECs).Methods: The primary BRECs were divided into 3 groups:the first group was exposed to a rang of LPC concentration (0-60umol/L);the second group was exposed to different glucose concentration (5.6, 30mmol/L)and mannitol concentration(20 mmol/L); the third group was exposed to LPC concentration (60umol/L) and glucose concentration (30mmol/L).The PDDGF-B in conditioned media of BRECs were assessed by ELISA kits. RT-PCR was used to detect the PDGF-B mRNA expression.Results:â‘ The PDGF-B in conditioned media and the levels of PDGF-B mRNA of BRECs was higher at LPC concentration 60umol/L compared to control after 12 hours.â‘¡The PDGF-B in conditioned media and the levels of PDGF-B mRNA of BRECs was higher at glucose cencontration 30mmol/L after 24 hours compared to 6 hours(p<0.01). Mannitol concentration 20mmol/L of osmotic pressure equivalent with glucose concentration 30mmol/L has no effect on the product of PDGF-B(P>0.05).â‘¢The PDGF-B in conditioned media and the levels of PDGF-B mRNA of BRECs were significantly higher at LPC concentration 60umol/L and glucose concentration 30mmol/L compared to control after 12 hours.Conclusion: These results demonstrate that LPC and glucose may enhance the expression of PDGF-B in BRECs, and with the synergistic effect of the two factors. These maybe result in the retinal neovascularization, which is one of the pathogenesis of dyslipidemia participating in the development of DR.