## 3 Results and Discussion
### The Effect of Fruit Enzymes at Differential Concentration on the Change of Various Floaters
It was found that in 14% of cases, traction forces from the vitreous jelly sometimes caused retinal tears [29]. If left untreated, the tears may induce to break and allow fluid to enter into the subretinal space which results in RD. Therefore, we developed a new method of pharmacologic vitreolysis using the fruit enzymes bromelain, papain and ficin. We suggested that there are at least three mechanisms for treating SVOs and floaters in our new method. First, metalloproteinase (MMPs) plays an important role in mediated message and proteolysis. Second, these three fruit enzymes have the ability to dissolve and cleave the abnormal ECM and vitreous opacities. Finally, these enzymes also support the antioxidant protection in oxidase stress from vitreous changes. In human body, the MMPs degraded the components of the complex ECM. It was also found that MMP-2 would cleave collagen Types I, II and III, while MMP-9 would cut collagen Types I, III and IV. Therefore, MMPs could clear SVOs in patients and decrease ocular floaters [30; 31]. The endogenous MMPs are even beneficial for pharmacologic vitreolysis and some vitreous-retinal diseases such as VMT and macular holes. Recently, it was revealed that different levels of MMP-2 and MMP-9 were found in fiction, bromelain and papain. Furthermore, endothelial progenitor cells also play an important role mediated by MMPs for matrix absorbing and remodeling. The MMPs, which were found in the vitreous of patients in the proliferative phase, could degrade the ECM, growth factors and compromised collagens. Furthermore, papain is found to have MMP-2 and MMP-9 abilities. Ficin was demonstrated to cut collagen I, II, III and IV from MMP-2 and MMP-9 biochemical functions. In addition, bromelain also has MMP-2 [32]. In other words, the mixture of fruit enzymes was considerable enough to have proteolytic function. In the past, vitreous floaters from blood clots and other opacities would be removed by laser vitreolysis and PPV. Now, however, taking the capsules of mixed-fruit-enzyme significantly decreased the persistence of floaters after the 3-month period. Hence, we proposed that oral fruit proteinase for dissolving and hydrolysis should be beneficial instead for laser and PPV. We analyzed the ability of bromelain, papain and ficin and revealed the hydrolytic function from fruit enzymes by MMPs. There are many uses for pineapple and its derived ingredients. For example, bromelain is one of the most popular fruit enzymes that is extracted from the pineapple stem and fruit. Recently, bromelain was introduced and originally applied to any protease from the plant family Bromeliaceae [16; 33]. The cysteine proteases, including papain, bromelain and ficin, are the most abundant in Bromeliaceae and belong to a free sulfhydryl group of a cysteine amino acid side chain that is required for function. It is reported that the medical advantages of bromelain may be due to its proteolytic and hydrolytic activities. Bromelain has hydrolytic, antifibrinolytic, anti-inflammatory and antithrombotic properties. The stem is the most common source because of its usable quantities. However, care should be taken because of its side effects of allergy and hyperglycemia. Papain belongs to a nonspecific cysteine proteinase characterized by broad substrate specificity; its hydrolysis makes papain an enzymatic supplement [34]. Papain is a proteolytic enzyme extracted from the latex of the raw fruit of the papaya plant that possesses hydrolytic enzymes that may enhance breaking down larger proteins into smaller fragments called peptides and amino acids. This is why papain is a common ingredient in meat tenderizers [35]. The mechanism of papain breaking peptide bonds involves the catalytic diisopropyl azodicarboxylate with a deprotonated cysteine that breaks the pieces of tissue into proteins, collagen and fibrils. Furthermore, papain can clear the fibrillary collagen II. Papain belongs to a type of the cysteine proteinase that cleaves propeptides.