anti-apoptosis effects of green tea in diagnostic and therapeutic doses of ionizing radiation

Introduction: patients who receive ionizing radiation for diagnosis or treatment may suffer side effects in normal tissues. radioprotective agents have the potential to decrease dna damage and free radicals produced by ionizing radiation. green tea is a natural product from the camellia sinensis plant and have been shown to have antioxidant and radioprotective properties. the aim of the present study is assessing the protective effect of green tea on lymphocytes affected by radiation injury.material and methods: blood samples was obtained from four adults healthy human and lymphocytes were extracted. afterward, lymphocytes were exposed to x-radiation by opg, cbct, ct and radiotherapy instruments. the protective effects of the green tea polyphenol on bcl-2 and bax genes expression levels were evaluated in cultured lymphocytes obtained from treated cells (24 h and 1 h before and 1 h after exposure to ionizing radiation) and non-treated cells (receiving x-radiation and non-receiving green tea).results: the results of this investigation demonstrated bax/bcl-2 ratio, as an index of the radiation sensitivity, was significantly decreased in groups which had been received dose of 2 gy in treated cells groups of 1 h before and 1 h after x-radiation (p<0.05).conclusion: the results indicated different effects of green tea on low and high doses of x-radiation. most protective effects of green tea as an apoptosis inhibitor were observed in high doses of ionizing radiation. consequently, green tea may be useful as an adjunct to radiotherapy and medical imaging to diminish apoptosis and side effects in normal tissues.