Osmolyte taurine induction in UVA exposed human retinal pigment epithelial cells.

AIM: To explore the osmolytes expression in ultraviolet (UVA) stressed human retinal pigment epithelial cells. METHODS: Osmolyte transporters and vascular endothelial growth factor (VEGF) messenger RNA (mRNA) were determined by real time polymerase chain reaction (PCR). Osmolyte uptake was measured by radioimmunoassay. VEGF concentrations were determined by immunoassay and enzyme-linked immunosorbent assay (ELISA). Osmolyte taurine transporter (TAUT) were silenced by siRNA technology. RESULTS: Hypertonicity accelerated osmolyte betaine uptake, myoinositol uptake, and taurine uptake, compared to normotonic stress. UVA irradiation also accelerated osmolyte transporters expression and osmolytes uptake. Especially, osmolyte taurine remarkably inhibited VEGF release induced by UVA irradiation. VEGF in the UVA stressed retinal pigment epithelial cell supernatant was accumulated slow after taurine preincubation. VEGF expression increased significantly in UVA-stressed cells after TAUT silencing. Moreover, taurine reduced the VEGF level in human ocular aqueous humor. CONCLUSION: The inhibition of VEGF by osmolyte taurine plays the crucial role in retina adaption to UVA irradiation.

Taurine reduces blue light-induced retinal neuronal cell apoptosis in vitro.

BACKGROUND: The massive uptake of organic compatible osmolytes is a self-protective response to multiple stressors. OBJECTIVE: This study aimed to determine the protective effects of the osmolyte taurine against blue light-induced apoptosis in retinal neuronal cells in vitro. METHODS: Real-time PCR was used to measure osmolyte transport. Radioimmunoassays were performed to measure osmolyte uptake. Cell Counting Kit-8 assays were conducted to measure cellular viability. Flow cytometry analysis was used to measure apoptosis. RESULTS: Compared with normotonic stress, hypertonic stress-induced uptake of osmolytes, including betaine, myoinositol, and taurine, into the retinal neuronal cells. Blue light increased osmolyte transporter mRNA expression together with osmolyte uptake. Furthermore, taurine significantly suppressed blue light-induced retinal neuronal cell apoptosis. CONCLUSION: The compatible osmolyte taurine may have an important role in cell resistance to blue light and cell survival.

Taurine prevents ultraviolet B induced apoptosis in retinal ganglion cells.

BACKGROUND: Compatible osmolytes accumulation is an active resistance response in retina under ultraviolet (UV) radiation and hypertonicity conditions. OBJECTIVE: The purpose of this research is to investigate the protective role of taurine on retina under UVB radiation. METHODS: Osmolytes transporters were measured by quantitative realtime PCR. Osmolytes uptake was estimated by radioimmunoassay. Cell viability was calculated by MTT assay. Cell apoptosis was measured by flow cytometry analysis. RESULTS: Hypertonicity accelerated osmolytes uptake into retinal ganglion cells (RGCs) including taurine, betadine, and myoinositol. UVB radiation increased osmolytes transporter expression and osmolytes uptake. In addition, osmolyte taurine remarkably prevented UVB radiation induced cell apoptosis in RGCs. CONCLUSIONS: The effect of compatible osmolyte taurine on cell survival rate may play an important role in cell resistance and adaption to UVB exposure.

Taurine Protects Lens Epithelial Cells Against Ultraviolet B-Induced Apoptosis.

BACKGROUND: The massive uptake of compatible osmolytes is a self-protective response shared by lens exposed to hypertonic stress and ultraviolet stress. OBJECTIVE: This study aimed to investigate the protective effects of taurine against ultraviolet B-induced cytotoxicity in the lens epithelial cells. METHODS: Real-time PCR was used to measure osmolytes transport. Radioimmunoassay was used to measure osmolytes uptake. Cell counting kit-8 assays were used to measure cellular viability. Flow cytometry analysis was used to measure apoptosis level. RESULTS: Compared with normotonic stress, hypertonic stress-induced osmolytes uptake into the lens epithelial cells such as betaine, myoinositol and taurine. UVB exposure increased osmolytes transporter mRNA expression together with osmolytes uptake. Moreover, taurine suppressed UVB-induced cell apoptosis in the lens epithelial cells significantly. CONCLUSIONS: The effect of compatible osmolyte taurine on cell survival rate may play an important role in cell resistance and adaption to UVB exposure.

Cardiac myocyte apoptosis in diabetic rats and effect of non-enzymatic glycosylation inhibitor / 中国组织工程研究

BACKGROUND: Oxygen-derived free radicals are produced during non-enzymatic glycosylation of diabetic protein and accompanied with decrease in nitrogen monoxide (NO) synthesis so as to cause the calcium increase in cell,evacuation of pykno-granule and apoptosis induced by activating endoenzyme.OBJECTIVE: To observe the effects of non-enzymatic glycosylation inhibitor-aminoguanidine on apoptosis of cardiac myocyte and cardiac function in diabetic rats.DESIGN: Completely randomized grouping design and controlled study.SETTING: Pharmacological Department of Jinzhou Medical College.MATERIALS: The experiment was completed at the Central Laboratory of Jinzhou Medical College between September 2002 and March 2003. Totally 54 male SD rats with 2-month old were selected.METHODS: Totally 36 rats were selected to establish diabetic model 60 mg/kg of streptozotocin were injected into the caudal vein. If blood glucose of rats was more than 16.7 mmol/L, the establishment of diabetic model was successful. Model rats were divided into diabetes group and aminoguanidine (AG) group with 18 in each group. Rats in each group were also divided into two 12-week groups with 8 and 12 respectively. Another 18 rats were determined as the control group at 2 time points: 12 weeks (n=8) and 24 weeks (n=10). Rats in each group were fed for 12 and 24in other two groups. Calculation of mass index was [heart (mg)/body mass (g)]. Myocardial tissue of left ventricle was taken out and observed with transmission electron microscope and then stained with in situ end-labeling (ISEL) method. Number of positive nucleus was counted with 10 × 10 ocular lens check system and with 10 fields ISEL method; meanwhile, their average was obtained.MAIN OUTCOME MEASURES: Whether there was apoptosis of cardiac cell and the effect on AG in changes of cardiac structure and function of diabetic rats or not.RESULTS: Eight rats were lost during the experiment because of death mass: That of rats in the 12-week and 24-week diabetic group was higher decrease and increase rate of pressure in left ventricle: That of rats in the 12-week and 24-week diabetic group was lower than that in the control in left ventricle: That in 24-week diabetes group was obviously lower than diabetic group was obviously more than that in AG group (P ＜ 0.01), and that in 24-week diabetes group was obviously more than that in 12-week Apoptosis could be observed in myocardial cell in diabetic group.CONCLUSION: Apoptosis of myocardial cell plays an important role in the development of heart failure in diabetic rats. AG can reduce the apoptosis of myocardial cell and decrease the myocardial pathomorphological abnormality.