| Abstract: | Cisplatin (CDDP) 是一種無機鉑類化療藥物，廣泛用於治療各種癌症，儘管有顯著的抗腫瘤活性，但也會對正常細胞產生毒性。CDDP引起之副作用有許多，包括骨髓抑制作用，將會造成化療藥物的使用受到限制。Quercetin是一種在植物中含量豐富的類黃酮，研究指出quercetin及其代謝物quercetin-3-O-glucuronide (Q3G) 具有多種的生理活性，亦可能降低化療藥物的副作用。我們先前的研究顯示，quercetin能夠抑制CDDP降低對腫瘤異種移植裸小鼠骨髓細胞數的作用。然而裸小鼠種有免疫缺陷問題，因此本研究中，我們使用具正常免疫系統的BALB/c 小鼠，探討quercetin對CDDP骨髓抑制作用的影響及可能的機制。BALB/c小鼠隨機五組分別為control組、單獨給予CDDP (7.5 mg/kg B.W.，腹腔注射，一週一次)，或CDDP合併quercetin腹腔注射 (10 mg/kg B.W.，一週三次；IQ) 或CDDP合併飼料含0.1% (LQ) 及1% quercetin (HQ)，處理時間為14天。結果顯示，CDDP顯著降低骨髓細胞、白血球、嗜中性球、單核球、紅血球及血小板的數量及血紅素濃度 (p<0.05)，CDDP合併含quercetin的飼料或IQ處理則會增加這些參數，且其效果給予IQ、HQ>LQ；相較CDDP組小鼠，IQ及HQ處理組也明顯有較高血液或/和骨髓造血生長因子interleukin 9 (IL-9)、granulocyte-macrophage colony-stimulating factor (GM-CSF) 與stem cell factor (SCF) 的含量，相反的，IQ、LQ及HQ處理則能降低血液或/和骨髓造血抑制因子tumor necrosis factor alpha (TNF-α) 及transforming growth factor beta 1 (TGF-β1) 及MDA濃度 (p<0.05)；小鼠生長和臟器重量上，IQ、LQ及HQ不但減少CDDP造成的體重、腓腸肌與副睪脂肪的流失及腎臟重量的下降 (p<0.05)，也能降低CDDP誘發的脾臟重量增加 (p<0.05)。
為驗證動物實驗的結果，我們利用小鼠骨髓細胞株32D探討quercetin及其代謝物Q3G在濃度0.2 μM下對CDDP (0.3 μM) 抑制32D細胞生長之影響。結果顯示quercetin及Q3G皆顯著 (p<0.05) 抑制CDDP誘發的32D細胞凋亡，同時也伴隨增加CDDP處理細胞的IL-9及GM-CSF的濃度 (p<0.05)，並顯著抑制TNF-α及TGF-β1濃度的升高 (p<0.05)。
綜合以上，我們的體內外研究顯示注射及飲食方式給予quercetin及其代謝物Q3G均會降低CDDP誘發的骨髓抑制，其機制與增加造血生長因子及抑制造血抑制因子有關。Cisplatin (CDDP) is an inorganic platinum-based chemotherapeutic which is being widely administered for treatment of various tumors. Despite the significant anti-tumor activities, cisplatin also shows cytotoxicities to normal cells. These side effects of CDDP are various including bone marrow suppression and may limit the use of CDDP. Quercetin is a flavonoid present abundantly in plants. Studies suggest that quercetin or its metabolites possess various bioactivities and may attenuate the side effects of chemotherapies. Our previous study show that quercetin increase bone marrow cell numbers in tumor-bearing nude mice exposed to CDDP. However, nude mice are immunodeficient. In the current study, we used BALB/c mice (with normal immune system) to investigate the effects of quercetin on myelosuppression induced by CDDP and explored the possible mechanisms. The BALB/c mice were randomly treated with CDDP (7.5 mg/kg B.W., once a week) alone, or in combination with quercetin for 14 days. Quercetin was given by intraperitoneal injection (10 mg/kg B.W., 3 times a week; IQ) or by a quercetin containing diet (0.1% or 1% quercetin diet; LQ and HQ, respectively). The results showed that CDDP significant decreased the numbers of bone marrow cell, total white blood cell, neutrophil, monocyte, red blood cell and platelet as well as the concentration of haemoglobin. CDDP in combination a quercetin containing diet or IQ tended to increased these parameters in the order IQ, HQ>LQ. Furthermore, our results showed that IQ and HQ significantly increased hematopoietic growth factor levels including interleukin 9 (IL-9), granulocyte-macrophage colony-stimulating factor (GM-CSF) and stem cell factor (SCF) levels in the plasma, bone marrow or both in mice exposed to CDDP. In contrast, IQ, LQ and HQ tended to decrease the levels of hematopoietic inhibitory factors, tumor necrosis factor alpha (TNF-αand transforming growth factor beta 1 (TGF-βMDA contents in the plasma and bone marrow. In addition, our results also showed that that IQ, LQ and HQ tended to decrease the loss of body, gastrocnemius muscle, epididymal fat and kidney weight induced by CDDP, while decrease the spleen weight increased by CDDP.
To confirm the in vivo findings, we used 32D cell line to study the influences of quercetin and its major metabolite, quercetin-3-O-glucuronide (Q3G), at 0.2 μM on the growth of 32D cells explored CDDP (0.3 μM). We found that both quercetin and Q3G significantly inhibited apoptosis (p<0.05). Accompany the finding, quercetin and Q3G increased the levels of IL-9 or GM-CSF, while decreased the levels of TNF-α and TGF-β1 in 32D cells.
In conclusion, our in vivo and in vitro results suggest that quercetin given by intraperitoneal injection or by a quercetin containing diet attenuate CDDP-induced myelosuppression. The mechanisms are associated with the upregulation of hematopoietic growth factors and the downregulation of hematopoietic inhibitory factors. |
