據世界衛生組織報告，成年人發生突發性聽損已是全球主要疾病之一，大多數的突發性耳聾可能會導致永久性的聽力障礙，當內耳組織因突發性耳聾發生時，會導致該組織區域血流量下降，引發缺血性之傷害，使葡萄糖與氧氣供應量不足(即Oxygen Glucose Deprivation)，會破壞粒線體，且產生大量自由基，導致大量毛細胞死亡，治療方式包括藥物及高壓氧等，治療效果有限無法令人滿意，此外高壓氧提供的高濃度氧氣可能會增加組織內的活性氧（ROS）容易導致耳蝸進一步損傷，因此研發新式內耳缺氧性損傷之療法是非常重要之研究議題。二甲雙胍(Metformin)的主要作用是活化單磷酸腺苷活化蛋白質激酶(AMP activated protein kinase, AMPK)降低合成代謝反應，對神經與聽力有保護作用，因此本論文製備經修飾二甲雙胍之包覆氧氣白蛋白微氣泡(MET-OMB)，用以代替原先的高壓氧治療策略，並合併超音波介導技術應用於治療內耳缺氧性損傷。
實驗結果中， 含氧微氣泡(OMB)與MET-OMB平均粒徑大小依序為1.75 ± 0.24µm、2.22 ± 0.25µm；表面電位依序為-12.26 ± 1.70mV、3.82 ± 1.00 mV，藉由濃度儀確認MET-OMB濃度為2.8 ± 1.25(×108 bubbles/mL)且MET吸附率為69.49 ± 2.98 %。透析袋藥物釋放實驗中，確認可藉由超音波誘發MET-OMB穴蝕效應將氧氣從透析袋釋出；在體外細胞實驗結果中(n=5)，以組織氧分壓與溫度監控儀測量培養液氧分壓變化，並藉由氧氣與葡萄糖掠奪之方式，確認HEI-OC1細胞的生存率，實驗組別分別為：No treatment(OGD)組、單純MET溶液浸泡與超音波組(OGD+MET/OGD+MET+US)、單純MET-OMB溶液浸泡與超音波組(OGD+MET-OMB / OGD+MET-OMB+US)。在體外細胞實驗中，超音波結合MET-OMB之細胞生存率可提升18.04%，ROS抑制效果為49.21%，在抑制細胞凋亡的部分，超音波結合MET-OMB的效果相較於單純使用MET高許多，證明可藉由吸附MET之含氧微氣泡經超音波施打後，提高保護對於缺血性損傷之細胞，也可以降低細胞ROS的產生，在細胞凋亡抑制的螢光染色影像結果也有相當好的表現。

According to the report of the World Health Organization (WHO), sudden deafness in adults is one of the main diseases in the world. Most sudden deafness may cause permanent hearing impairment. When sudden deafness occurs due to damage to the inner ear, the blood flow in the tissue is reduced, causing ischemic damage and insufficient glucose and oxygen supply (Oxygen Glucose Deprivation, OGD). At this time, the mitochondria of the earing cell is damaged and generates a large number of free radicals, resulting in the death of a large number of hair cells. Treatment methods include drugs and hyperbaric oxygen, etc. However, the treatment effect is limited and unsatisfactory. The high concentration of oxygen provided by hyperbaric oxygen may increase the reactive oxygen species (ROS) in the tissue and easily lead to further damage to the cochlea. Therefore, the development of a new treatment platform for inner ear hypoxic injury is very important. In addition, the main function of Metformin (MET) is to activate adenosine monophosphate-activated protein kinase (AMP activated protein kinase, AMPK) to reduce the anabolic reaction, and has protective effects on nerve and hearing. In this thesis, a new Metformin coating oxygenated albumin microbubble (MET-OMB) were prepared, used to replace the original hyperbaric oxygen therapy strategy, and combined with ultrasound-mediated technology for the treatment of hypoxic damage of the inner ear.
In the experimental results, the mean diameters of oxygen-containing microbubbles (OMB) and MET-OMB are 1.75 ± 0.24 µm and 2.22 ± 0.25 µm, and the surface potentials are -12.26 ± 1.70 mV and 3.82 ± 1.00 mV. The concentration of the MET-OMB was 2.8 ± 1.25 (×108 bubbles/mL) and the coating efficancy of MET was 69.49 ± 2.98 %. In the drug release experiment of the dialysis bag, it was confirmed that the cavitation effect of MET-OMB induced by ultrasound can release oxygen from the dialysis bag; in the results of the in vitro cell experiment (n=5), the oxygen monitoring systemt was used to measure changes in the partial pressure of oxygen in the culture liquid. Then, the survival rate of OGD HEI-OC1 cells was confirmed. The in vitro experimental groups were: No treatment (OGD), MET alone (OGD+ MET), ultrasound combined with MET (OGD+MET+US), MET-OMB alone (OGD+MET-OMB) and ultrasound combined with MET-OMB (OGD+MET-OMB+US). In the in vitro cell experiments, the cell survival rate of OGD+MET-OMB+US can be increased by 18.04%, and the ROS inhibition effect is 49.21%. In the part of inhibiting cell apoptosis, the effect of OGD+MET-OMB+US is compared with that of MET alone. It is much higher, which proves that the oxygen-containing microbubbles adsorbed by MET can improve the protection of cells against ischemic damage after ultrasonic treatment, and can also reduce the production of ROS in cells. The results of fluorescence microscope images of cell apoptosis inhibition in OGD+MET-OMB+US group also has good performances.

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