姜黄素抑制 N-甲基-N-亚硝脲诱导的 Sprague-Dawley 大鼠光感受器细胞凋亡。

Curcumin suppresses N-methyl-N-nitrosourea-induced photoreceptor apoptosis in Sprague-Dawley rats.

机构信息

Department of Pathology II, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka 573-1010, Japan.

出版信息

In Vivo. 2013 Sep-Oct;27(5):583-90.

Abstract

AIM

Retinitis pigmentosa is a group of inherited neurodegenerative human diseases characterized by the loss of photoreceptor cells by apoptosis and lead to eventual blindness. A single intraperitoneal (i.p.) injection of N-methyl-N-nitrosourea (MNU), an alkylating agent, causes photoreceptor cell apoptosis within seven days in rats. Curcumin is a polyphenolic natural product with pluripotent properties including antioxidant activity. The purpose of the present study was to evaluate the efficacy of curcumin against photoreceptor apoptosis in a MNU-induced retinal degeneration rat model.

MATERIALS AND METHODS

Seven-week-old female Sprague-Dawley rats received a single i.p. injection of 40 mg/kg MNU. Three days prior to MNU injection, daily i.p. injections of 100 or 200 mg/kg curcumin were started, and the injections were continued once daily until sacrifice. Rats were sacrificed at 6, 12, 24 and 72 h, and 7 days after MNU, and their eyes were examined morphologically and morphometrically to evaluate the photoreceptor cell ratio and retinal damage ratio in hematoxylin and eosin-stained sections. Retinal 8-hydroxy-2-deoxyguanosine (8-OHdG) levels were quantified by enzyme-linked immunosorbent assay (ELISA), and the apoptotic cell ratio in photoreceptor cells was determined in situ by TdT-mediated dUTP-digoxigenin nick-end labeling (TUNEL).

RESULTS

Curcumin (200 mg/kg) significantly (p<0.01) suppressed the loss of photoreceptor cells, as determined by the photoreceptor cell ratio at the central retina seven days after MNU, and this effect was dose-dependent. At 12 h after MNU injection, when the oxidative DNA damage caused by MNU peaked, curcumin significantly reduced the level of 8-OHdG (0.78 vs. 0.50 ng/ml) (p<0.05) and the percentage of TUNEL-positive photoreceptor cells (17.5% vs. 10.8%) (p<0.05) as compared with MNU-exposed, curcumin-untreated retina, respectively.

CONCLUSION

Curcumin inhibited MNU-induced photoreceptor cell apoptosis by suppressing DNA oxidative stress. These findings indicate that curcumin may help to suppress the onset and progression of human retinitis pigmentosa.

摘要

目的

色素性视网膜炎是一组遗传性神经退行性人类疾病，其特征是光感受器细胞通过细胞凋亡而丧失，最终导致失明。单次腹腔内（i.p.）注射亚硝甲基脲（MNU），一种烷化剂，可在大鼠中在七天内引起光感受器细胞凋亡。姜黄素是一种具有多种特性的多酚天然产物，包括抗氧化活性。本研究的目的是评估姜黄素对 MNU 诱导的视网膜变性大鼠模型中光感受器细胞凋亡的疗效。

材料和方法

7 周龄雌性 Sprague-Dawley 大鼠接受单次腹腔内注射 40mg/kg MNU。在 MNU 注射前 3 天，开始每日腹腔内注射 100 或 200mg/kg 姜黄素，直至处死。大鼠分别于 MNU 后 6、12、24 和 72 小时以及 7 天处死，对其眼睛进行形态学和形态计量学检查，以评估苏木精和伊红染色切片中光感受器细胞的比例和视网膜损伤比例。通过酶联免疫吸附试验（ELISA）定量测定视网膜 8-羟基-2-脱氧鸟苷（8-OHdG）水平，并通过末端转移酶介导的 dUTP-地高辛缺口末端标记（TUNEL）原位测定光感受器细胞中的凋亡细胞比例。

结果

姜黄素（200mg/kg）显著（p<0.01）抑制了 MNU 后 7 天中央视网膜光感受器细胞的丧失，且这种作用呈剂量依赖性。在 MNU 注射后 12 小时，当 MNU 引起的氧化 DNA 损伤达到峰值时，姜黄素显著降低了 8-OHdG 水平（0.78 与 0.50ng/ml）（p<0.05）和 TUNEL 阳性光感受器细胞的百分比（17.5%与 10.8%）（p<0.05）与 MNU 暴露、未用姜黄素处理的视网膜相比。