|Abstract: ||先前本實驗室之研究指出，鋅可以作為刺激紅血球生成之訊號，能在惡劣環境中，快速刺激魚類生成新生紅血球，減緩貧血；而在其他物種，很可能也會有此種現象。為了解在大鼠，外來之鋅能否刺激其增生紅血球，乃以 Phenylhydrazine (PHZ) 溶液腹腔注射大鼠，形成溶血性貧血。再施打不同濃度 (0，4.5，6.0，9.0 mg Zn/kg body) 之硫酸鋅溶液於貧血大鼠腹腔內，靜養兩天，結果發現注射硫酸鋅之大鼠，其 RBC 之平均值由 3.33 提高至 4.54、7.75，及5.02 × 106 cells/mm3，Hematocrit 與 Hemoglobin 之平均濃度也提高。且貧血大鼠在施打 ZnSO4 後，血液中會增生許多細胞尺寸 5 μm 左右之細胞。血液經過 New methylene blue (NMB) 及 Transferrin receptor (CD-71) 免疫螢光染色後，得知此增生之細胞為網狀紅血球，其量約為血液血球之 50%。貧血大鼠在施打 ZnSO4 後，會增生許多新生之網狀紅血球，證明鋅刺激紅血球之功能，確實也存在於哺乳類動物中。鯉魚、鯽魚因本身儲有多量之鋅，故可用以刺激其造血器官增生紅血球，但是，其他動物沒有相似之鋅儲存系統，必須藉由注射或食物攝取，由體外供應適當多餘之鋅，來刺激紅血球之增加。針劑的使用，至今仍存在一定之風險。故以口服，較為適宜。使用口服鋅劑之時，鋅的型態 (form) 其為重要。無機型態，易與腸胃中之其他食物成分結合造成沉澱，導致較低的吸收量；胺基酸型態，在其他研究中已發現吸收效果高於硫酸鋅；存在於生物體中，與蛋白質結合之鋅――「生物鋅」，吸收效果可能更好，但無具體研究。故本報告使用不同種型態之鋅化合物，包括無機鋅 (硫酸鋅)、胺基酸鋅 (甘胺酸鋅)、生物鋅 (鯉腸之鋅及牡蠣之鋅)，餵食缺鋅飼料製造之「缺鋅小鼠」，了解對何種鋅劑之吸收最佳。實驗後，發現缺鋅會使小鼠體重下降，血清鋅濃度亦明顯下降。以四種不同型態之鋅劑，餵食「缺鋅小鼠」兩週後，發現餵食含 30 mg Zn/kg diet 之 Oyster-Zn飼料組小鼠，不論在體重、肝臟重量之恢復，或血漿中鋅濃度的提升，都優於其他三種飼料，復鋅效果最佳。為知何種型態之鋅劑，最能紓解貧血小鼠之貧血狀況，乃以經 PHZ 注射而貧血之小鼠進行實驗。經餵食硫酸鋅、甘胺酸鋅及 Oyster-Zn 一週後，發現不論哪種鋅來源，皆可使貧血小鼠之血液特性恢復與對照組相近數值。紅血球形狀也恢復近似對照組之血球。然而在 Oyster-Zn 組骨髓細胞的鋅濃度為控制組之 2.6 倍 (3.98 ± 2.20 比 1.52 ± 0.51 μg Zn/106 bone marrow cells)，表示鋅可能被吸收至骨髓，並刺激骨髓細胞產生新生紅血球。經 Giemsa 染色與 CD-71 免疫螢光染色後，可觀察到在 Oyster-Zn 組的骨髓細胞中，含有許多新生紅血球細胞，而在硫酸鋅及甘胺酸鋅組則無。即 Oyster-Zn 具有刺激小鼠產生更多新生紅血球之潛力。綜合以上結果，可知添加牡蠣作為飼料之鋅來源，能有效刺激小鼠骨髓細胞產生新生網狀紅血球，緩解「缺鋅小鼠」之缺鋅，與「PHZ 貧血小鼠」之貧血。|
Zinc is a signal to stimulate red blood cells formation in fish to alleviate anemia in harsh environment, it is very possible that this mechanism also exist in other animals including mammals. In order to find out whether exogenously zinc can also stimulate red blood cell formation in rats, hemolytic anemia rats were induced by intraperitoneal injection of phenylhydrazine (PHZ). The PHZ-induced anemia rats were then injected with different concentration of zinc sulfate solution (0, 4.5, 6.0, and 9.0 mg Zn/kg body) and rested for two days. The results showed that the mean value of RBC increased from 3.33 to 4.54, 7.75, and 5.02 × 106 cells/mm3, respectively, and the levels of hematocrit and hemoglobin also increased. After the injection of ZnSO4, many new cells having cell size about 5 μm were found in anemia rats, and these cells were identified to be reticulocytes (new red blood cells) which composing about 50% of the blood cells. Injection of ZnSO4 to PHZ-induced anemia rats do proliferate new reticulocytes. Zinc is also a signal in stimulating red blood cell formation in mammals. There are two ways to supply exogenous zinc to the rats or mice, either by injection or by oral administration. Because there is still a certain risk by using injection, oral administration may be a better option. In oral administration the form of zinc is important. Inorganic zinc such as zinc sulfate has a low absorption rate because it combines with other food ingredients. Zinc in the form of combining with amino acid has been found to have higher absorption rate than zinc sulfate. Bio-zinc, zinc combined with protein and presented in the organism, has been suggested might have the best absorption rate, but have not definite study yet. Therefore, in this report 4 different zinc forms, including inorganic zinc (zinc sulfate), zinc amino acid (zinc glycinate) and bio-zinc (zinc from the common carp and from the oysters) were studied. Zinc deficiency mice were produced by feeding the mice with zinc deficient diet for 2 weeks. It was found that zinc deficiency resulted the body weight of the mice dropped and the zinc level in the plasma decreased. The 4 groups of diets containing different zinc form (each has 30 mg Zn/kg diet) were supplemented to the zinc-deficient mice for 2 weeks. It was found that the group supplied with oyster-zinc was the best choice, because the body weight and liver weight were higher than other groups, and the plasma zinc level increased to normal level. Mice were injected with PHZ and produced PHZ-induced anemia mice. Three different zinc form diets, including zinc sulfate, zinc glycinate and oyster-zinc diets were fed to the anemia mice for 1 week. The results showed that all the 3 kinds of diet resumed the hematology value of the mice similar to the control group. Zinc levels in the bone marrow cells of the mice were investigated. It was found that the oyster-Zn group had a higher zinc level which was 2.6 times higher than that of control group (3.98 ± 2.20 vs. 1.52 ± 0.51 μg Zn/106 bone marrow cells). In smears with Giemsa staining and CD-71 immunofluorescence staining, the bone marrow cells of oyster-Zn group mice showed many immature erythrocytes but not in the zinc sulfate or zinc glycinate group’s mice. The results showed that oyster-Zn has the potential to stimulate mice bone marrow cells to produce more new immature erythrocytes, probably by the stimulation of zinc. In conclusion, the addition of oyster as the exogenous zinc source for diet can effectively stimulate the bone marrow cells of mice to differentiate into reticulocytes. It may alleviate the zinc deficiency in "zinc deficiency mice" and the anemia of "PHZ-induced anemia mice".