[show abstract][hide abstract] ABSTRACT: Recent reports show that ER stress plays an important role in diabetic retinopathy (DR), but ER stress is a complicated process involving a network of signaling pathways and hundreds of factors, What factors involved in DR are not yet understood. We selected 89 ER stress factors from more than 200, A rat diabetes model was established by intraperitoneal injection of streptozotocin (STZ). The expression of 89 ER stress-related factors was found in the retinas of diabetic rats, at both 1- and 3-months after development of diabetes, by quantitative real-time polymerase chain reaction arrays. There were significant changes in expression levels of 13 and 12 ER stress-related factors in the diabetic rat retinas in the first and third month after the development of diabetes, Based on the array results, homocysteine- inducible, endoplasmic reticulum stress-inducible, ubiquitin-like domain member 1(HERP), and synoviolin(HRD1) were studied further by immunofluorescence and Western blot. Immunofluorescence and Western blot analyses showed that the expression of HERP was reduced in the retinas of diabetic rats in first and third month. The expression of Hrd1 did not change significantly in the retinas of diabetic rats in the first month but was reduced in the third month.
Experimental Diabetes Research 01/2012; 2012:743780. · 1.89 Impact Factor
[show abstract][hide abstract] ABSTRACT: 58-kilodalton inhibitor of protein kinase (P58(IPK)) plays an important role in preventing endoplasmic reticulum (ER) stress. It is an interferon-induced kinase that targets the eukaryotic translation initiation factor eukaryotic initiation factor 2 alpha. The aim of this study was to determine the roles of P58(IPK) in protecting against diabetic retinopathy (DR) by inhibiting ER stress-signaling mediators.
A rat diabetic model was established by intraperitoneal injection of streptozotocin. Overexpression of P58(IPK) was achieved by intravitreal injection of purified recombinant adeno-associated virus vector (rAAV2)-P58(IPK) or transfection into rat retinal capillary endothelial cells. Retinal vascular permeability was determined by assessing the Evans Blue retinal leakage. To downregulate the P58(IPK) level in cultured rat retinal capillary endothelial cells, pGIPZ-P58(IPK) RNA interference (P58(IPK)RNAi) was introduced in these cells. Real time reverse transcription (RT)-PCR and western blot analyses were performed to evaluate the mRNA and protein levels of Core/emopamil binding protein (C/EBP) homologous protein (CHOP), vascular endothelial growth factor (VEGF), and tumor necrosis factor-α (TNF-α).
Retinal blood vessel leakage was significantly decreased in rAAV2-P58(IPK)-transfected diabetic rats compared with the control diabetic rats. Both mRNA and protein levels of CHOP, TNF-α, and VEGF in the retina of diabetic rats were remarkably reduced in P58(IPK)-transfected rats. In vitro study further demonstrated that overexpression of P58(IPK) downregulated the expression of CHOP, TNF-α, and VEGF under high glucose conditions, whereas introduction of P58(IPK)RNAi enhanced the expression of CHOP, TNF-α, and VEGF.
These results revealed the protecting role of P58(IPK) against ER stress-mediated DR in diabetic rats, suggesting that P58(IPK) may act as a DR-resistant gene during diabetes.
[show abstract][hide abstract] ABSTRACT: To investigate the influence of He-Ne lasers on scar formation in the filtration canal after trabeculectomy in a rabbit model, as well as to explore the mechanisms for preventing scar formation when using He-Ne lasers in vivo.
Experiment 1: Four groups were established (four eyes in each group). In 12 eyes, the upper nasal limbus area next to the upper rectus muscle received 10 minutes of He-Ne laser irradiation (100, 150, 200mW/cm(2); 60, 90, 120J/cm(2)) every day for three days. Four eyes served as controls. Twenty-four hours after the final irradiation, the rabbits were sacrificed and the irradiated tissue was excised, fixed with paraformaldehyde and tested for proliferating cell nuclear antigen (PCNA), connective tissue growth factor (CTGF) and apoptosis (TUNEL). Experiment 2: Forty-two rabbits were randomly divided into two groups and standard trabeculectomy was performed in the right eyes either after 200mW/cm(2) He-Ne laser irradiation or not in the filtration area. The expression of PCNA and CTGF, apoptosis and collagen density in the filtration area were tested on the 7(th), 14(th) and 28(th) day after surgery.
Experiment 1: There were no more PCNA and CTGF positive cells in the He-Ne irradiation group than in the control group. No apoptotic cells were found in either group. Experiment 2: The expression of PCNA and CTGF was lower in the He-Ne irradiation group than in the control group on the 7(th) and 14(th) day after trabeculectomy surgery (P<0.05); no apoptotic cells were detected in either group. Collagen density was significantly lower in the He-Ne irradiation group than in the control group on the 14(th) and 28(th) day after surgery (P<0.05).
Pretreating the filtration area with 200mW/cm(2) (120J/cm(2)) of He-Ne laser irradiation may be helpful in preventing scar formation after trabeculectomy, possibly due to the downregulation of the expression of PCNA, CTGF and collagen synthesis in fibroblasts.
International Journal of Ophthalmology 01/2010; 3(2):132-6. · 0.12 Impact Factor
[show abstract][hide abstract] ABSTRACT: To observe the effect of endothelin-1 (ET-1) on the cytoskeleton protein F-actin of cultured human trabecular meshwork (HTM) cells.
CULTURED HTM CELLS WERE RANDOMLY DIVIDED INTO FOUR GROUPS: control group, low-dose ET-1 (10(-9) mol/L) treatment group, middle-dose ET-1 (10(-8) mol/L) treatment group, and high-dose ET-1(10(-7) mol/L) treatment group. After treated with ET-1, the expression of cytoskeleton protein F-actin in trabecular meshwork was analyzed with Western-blot and the distribution of F-actin was detected with FITC-Phalloidin probe.
ET-1 dose-dependently and significantly increased F-actin in trabecular meshwork cells (P<0.05). The F-actin stress fiber and periphery actin fiber highly increased and manifested mild reorganization after treated with ET-1; and there were much more cell-to-cell and cell-to-extracellular matrix attachments formation in ET-1 treated HTM cells than that in the untreated HTM cells.
ET-1 promotes the expression of cytoske- leton protein F-actin and induced the trabecular meshwork actin cytoskeleton reorganization.
International Journal of Ophthalmology 01/2010; 3(1):61-3. · 0.12 Impact Factor
[show abstract][hide abstract] ABSTRACT: To investigate the influence of He-Ne laser on connective tissue growth factor (CTGF) expression and collagen formation of fibroblast in filtration site after trabeculectomy in rabbit, and to discuss the mechanism for preventing scar formation with He-Ne laser in vivo.
The upper nasal limbus area next to the upper rectus muscle in right eyes received 10 minutes He-Ne laser irradiation (200mW/cm(2)) every day for three days, the left eyes served as control. Twenty-four hours after the last irradiation, both eyes of the rabbits were took trabeculectomy surgery. The expressions of CTGF in the filtration area were tested on the 7(th), 14(th) and 28(th) day after surgery and collagen density was tested on the 14(th) and 28(th) day after surgery. Each of the time point had 7 rabbits.
The expression of CTGF was lower than that of the control group's on the 7(th) and 14(th) day after trabeculectomy surgery (P=0.01, P=0.005). When examined on the 14(th) and 28(th) day, the collagen density of irradiation group were significantly lower than that of the control group's (P=0.013, P=0.01).
Pretreating the filtration area with 200mW/cm(2) He-Ne laser may be helpful in preventing scar formation after trabeculectomy in rabbit, possibly due to downregulation of the expression of CTGF and collagen synthesis in fibroblasts. He-Ne laser may be developed into a new scar preventing method in filtration surgery.
International Journal of Ophthalmology 01/2010; 3(3):192-5. · 0.12 Impact Factor