探討異厚朴酚對於Cisplatin造成之睪丸毒性之影響

Abstract

Cisplatin 或是 cis-diamminedichloroplatinum [II]是一種含鉑的抗癌藥物，廣泛使用於治療多種的癌症，包括卵巢癌、睪丸癌以及頭頸部的固態實質瘤，然而在雄性中cisplatin所衍生的其中一個副作用為睪丸毒性，其在睪丸造成的傷害包含生殖上皮的細胞凋亡、長時間的無精症和睪丸萎縮。雖然目前對於cisplatin造成的睪丸毒性機制尚未全面瞭解，許多研究認為氧化緊迫為 cisplatin引起細胞毒性的重要原因之一。 異厚朴酚為雙酚類化合物萃取自Magnolia officinalis 樹皮，其早已廣泛使用於中草藥，它具有多種生物活性包括抗過敏、抗癌、抗焦慮、抗憂鬱以及抗氧化。其中，異厚朴酚被證實具有良好的抗氧化功效且其抗氧化功效為維他命E的1000倍，因此異厚圤酚有機會可以用於減緩cisplatin造成的睪丸毒性。 本篇研究藉由cisplatin誘發睪丸毒性的老鼠動物模式與活體外TM4睪丸賽特利細胞測試來探討異厚朴酚的保護效果。在小鼠的活體試驗中，我們發現cisplatin會造成睪丸細精小管中生殖上皮細胞的嚴重減少，而在給予異厚朴酚的組別中則觀察到生殖上皮細胞的傷害較為趨緩。另外，相較於cisplatin的組別發現精子總量下降，在給予異厚朴酚的組別中有較多的精子儲存在尾端附睪的管腔中(cisplatin和cisplatin加上異厚圤酚分別為13.8% 和62.2%)。 此外，在cisplatin加上異厚朴酚的組別，我們觀察到氧化損傷蛋白8-OHdG和細胞凋亡指標蛋白caspase-3的減少，而在TM4賽特利細胞的活體外研究中則發現異厚朴酚可以有效的降低cisplatin所造成的活性氧化物生成。綜合以上的結果，我們認為異厚朴酚具有減緩cisplatin所引起之睪丸毒性的潛力，其保護效果可能來自減少氧化損傷和細胞凋亡。

Cisplatin (cis-diamminedichloroplatinum [II]) is a platinum-containing drug widely used for chemotherapy to efficaciously treat various cancers, including ovarian and testicular cancers, and solid tumors of the head and neck. In male, one of its associated side effects is testicular toxicity. The side effects observed in the testis after cisplatin administration are germ cell apoptosis, long–lasting azoospermia, and testicular atrophy. Although the underlying mechanism of cisplatin-induced testicular toxicity is not fully understood, many studies suggested that oxidative stress might be involved in cisplatin-induced toxicity. Honokiol (HNK) is a biphenolic compound obtained from the bark of Magnolia officinalis which has been widely used in Chinese medicine. HNK exhibits multiple bioactivities, including anti-allergy, anti-anxiety, anti-cancer, anti-depression, and anti-oxidation. Moreover, HNK is a highly effective antioxidant which is 1000 times more effected than the Vitamin E. Therefore, HNK might be a promising compound to minimize the testicular toxicity caused by cisplatin. In this study, we examined the effect of HNK using both in vivo cisplatin-induced testicular injury mouse model and in vitro mouse sertoli cells (TM4) culture-based analyses. In the cisplatin-induced testicular injury mouse model, a significant decrease of spermatogenic cells in the seminiferous tubules was observed after cisplatin administration. Interestingly, with HNK supplementation, the testicular structure (layers of the cells) was less damaged. In the epididymis, the presence of sperm cells in the cauda lumen was evaluated. In contrast to cisplatin-treated group, when HNK was used in combination with cisplatin, a higher percentage (13.8% vs. 62.2% for cisplatin and cisplatin/HNK group, respectively) of sperm cells were observed in the epididymal lumen. Furthermore, in cisplatin/HNK group, we observed a decreased level of 8-hydroxyguanosine expression, a DNA oxidative stress marker, and caspase-3, an apoptosis marker. From in vitro study, cisplatin/HNK incubation decreased the generation of reactive oxygen species in TM4 cells. We hypothesize that HNK can potentially be used to reduce cisplatin-induced testicular toxicity, based on data presented in this thesis, the protective effect of HNK seems to be related to the suppression of oxidative stress and anti-apoptosis.