title: Effects of different concentrations of tetramethylpyrazine, an active constituent of Chinese herb, on human corneal epithelial cell damaged by hydrogen peroxide.
abstract: OBJECTIVE
  To discuss the effects of different concentrations of tetramethylpyrazine (TMP), an active constituent of Chinese herb, on damaged Shandong human corneal epithelial cell (SDHCEC) induced by hydrogen peroxide.
  
  
  METHODS
  We detected the combined effects of TMP with concentrations ranging from 4 mg/mL to 0.03 mg/mL and 800 µM hydrogen peroxide on SDHCEC. The methyl thiazolyl tetrazolium (MTT) assay was processed at 3, 6 and 12h separately while the detection of cell apoptosis at 6h only by flow cytometry.
  
  
  RESULTS
  The viability of SDHCEC with 0.5 mg/mL, 0.25 mg/mL, 0.125 mg/mL and 0.06 mg/mL TMP joint with 800 µM hydrogen peroxide at 3h and 6h was significantly higher than that with 800 µM hydrogen peroxide only, P<0.05. However, except 0.25 mg/mL, TMP with other concentrations joint with 800 µM hydrogen peroxide at 12h could not significantly inhibit decreased SDHCEC viability induced by 800 µM hydrogen peroxide. At 12h, TMP of 0.5 mg/mL, 0.25 mg/mL, 0.125 mg/mL and 0.06 mg/mL could significantly inhibit SDHCEC early apoptosis induced by 800 µM hydrogen peroxide, most remarkable at 0.25 mg/mL TMP, P<0.05.
  
  
  CONCLUSIONS
  Our results suggested that hydrogen peroxide can induce apoptosis related damage to SDHCEC. TMP can protect SDHCEC from the damage, and the protective effects may be associated with its anti-apoptosis mechanism.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China ; Department of Ophthalmology, Huizhou First Hospital, Huizhou 516001, Guangdong Province, China.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China.
authors.forename: Xin-Guo
authors.initials: XG
authors.lastname: Deng
authors.affiliation: Department of Ophthalmology, Huizhou First Hospital, Huizhou 516001, Guangdong Province, China.
authors.forename: Shi-Hua
authors.initials: SH
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China.
authors.forename: Mei-Feng
authors.initials: MF
authors.lastname: He
authors.affiliation: Department of Ophthalmology, Huizhou First Hospital, Huizhou 516001, Guangdong Province, China.
authors.forename: Dong-Qing
authors.initials: DQ
authors.lastname: Zhao
keywords: apoptosis; cell viability; human corneal epithelial cell; hydrogen peroxide