ABSTRACT
AIM: To study the effects of Tetramethylpyrazine (TMP) on retinal pigment epithelium (RPE) degeneration, choroidal blood flow and oxidative stress of RPE cells.METHODS: The 35mg/kg NaIO3-induced RPE degeneration rat eyes was given 25μg 1% TMP eye drops 3 times a day for 7 days before NaIO3 injection, and then 2 to 4 weeks after NaIO3 injection. RPE function was measured with c-wave of electroretinogram (ERG). Colored microsphere technique was used for in vivo experiments to determine the choroidal blood flow in ocular hypertensive (40mmHg) rabbit eyes. Methylthiazoltetrazolium (MTT) assay was used to study in vitro effect of TMP on various oxidants induced injury in the hRPE (ARPE-19 (ATCC, Manassas, VA, USA)) . RESULTS: Two weeks after NaIO3 injection, the amplitude of ERG c-wave fell markedly in NaIO3 group to 36% of control group (P<0.01). No apparent difference was observed in TMP+NaIO3 group. Four weeks later, the NaIO3 group fell to 46% of control group (P<0.01), while the TMP+NaIO3 group fell to only 77% of control group (P<0.01). There was a 67% reversal of the ERG c-wave by TMP as compared to NaIO3 group (P<0.01). The choroidal blood flow was significantly increased at all time points (at 30, 60 and 120 minutes after TMP instillation) as compared with corresponding controls. TMP had no effect on hypoxia-(1%O2), t-BHP- and H2O2-induced damage in RPE cells. 10μg/mL TMP could reverse 1 and 3mmol/L NaN3-induced loss of viability of RPE by 18.5% (P<0.01) and 23% (P<0.01), respectively. 30μg/mL TMP could reverse 30 and 100mmol/L NaIO3 induced loss of viability of RPE by 18.1% (P<0.05) and 16.8% (P<0.01), respectively.CONCLUSION: TMP can significantly protect RPE from NaIO3 induced degeneration in vivo and oxidative stress in vitro and can increase choroidal blood flow markedly in vivo .
ABSTRACT
AIM: To evaluate the antioxidant activity of naringenin in human retinal pigment epithelium (ARPE-19) cells andhuman umbilical vein endothelial cells (HUVEC).·METHODS: MTT assay was used to measure theviability and proliferation of ARPE-19 cells and HUVEC.·RESULTS: Three and 10mg/L naringenin significantlyincreased the proliferation of ARPE-19 cells by 10.8% and11.4%, respectively. Ten mg/L naringenin increasedhypoxia-, 0.3mmol/L NAN3-, and 200μmol/L H2O2- induced damage of ARPE-19 cells by 55.2%, 69.2%, and50.3%, respectively. One mg/L naringenin increased theviability of 50μmol/L t-BHP-, and 30mg/L NalO3-treatedARPE-19 cells by 20.2% and 30.4%, respectively. Thirtymg/L naringenin also increased the proliferation of50μmol/L t-BHP-treated ARPE-19 cells by 32.2%, and1mg/L naringenin increased the proliferation of 30, 100and 300 mg/L NalO3-treated ARPE-19 cells by 30.3%,10.3% and 18.5%, respectively. The reduction of HUVECwas 23.9%, 70.4% and 77.9% in the 3, 10 and 30mg/Lnaringenin-treated groups, respectively. Furthermore, 1and 3mg/L naringenin increased hypoxia-induced damagein HUVEC by 10.7% and 13.1%, and 300mg/L NalO3- induced damage in HUVEC by 41.2% and 37.7%. Threemg/L naringenin increased 200 and 400μmol/L H2O2-in-jured HUVEC by 20.1% and 21.5%, respectively.·CONCLUSION: Naringenin increases the proliferation ofARPE-19 cells and inhibites the growth of HUVEC, and haspotent antioxidant activity in ARPE-19 cells and HUVEC.