| Gastric ulcer is the most common diseases affecting human health.It is a common peptic ulcer,which has a higher risk of morbidity among middle-aged and elderly people,irregular diets and people who work overtime for a long time.The main factors that cause peptic ulcers are the use of non-steroidal anti-inflammatory drugs(NSAIDs)and Helicobacter pylori infection.Gastric ulcers can cause mild or moderate burning and stomach upset.In severe cases,they can cause gastric outlet obstruction and bleeding,haemorrhage,and gastric cancer etc.Although there are many ways to treat gastric ulcer in clinic,the therapeutic effect is not ideal.The development of a new method for effective treatment of gastric ulcer is of great significance for improving the treatment effect of gastric ulcer and blocking the progression of the disease.In this study,based on the ethanol-induced gastric ulcer mouse model,keratin-A6 ACA composite microspheres were constructed for the treatment of ethanol-induced gastric ulcer mice,and the keratin-encapsulated IR783 fluorescent dye was prepared by O/W/O method.A6 ACA composite microspheres are used for the diagnosis and treatment of gastric ulcer injury.We evaluated the therapeutic effect of keratin-A6 ACA composite microspheres on gastric ulcers through gross inspection of gastric mucosal hemorrhagic lesions,histopathological section observation,oxidative stress detection and serum inflammatory factor expression.The specific adhesion and tissue repair effect of keratin in the ulcer makes the composite microspheres reach the mouse stomach and can quickly adhere to the injured part of the gastric mucosa.It can isolate the acidic gastric juice from secondary damage to the gastric ulcer,and diagnose the damage of the ulcer by embedding fluorescent material.In addition,the keratin material in the composite microsphere can play a hemostatic and anti-inflammatory effect,improve the repair effect,and provide a new idea and method for the treatment of gastric ulcer.The main research contents of this paper include:(1)Keratin was obtained from human hair by chemical reduction,and keratin and A6 ACA were grafted through amide reaction to obtain keratin-A6 ACA composite microspheres.SEM results showed that the keratin-A6 ACA composite microspheres are spherical,and FTIR analysis showed that the amide bond absorption peak intensity of the microspheres is stronger than that of pure keratin,and the characteristic absorption peaks of the A6 ACA hydrogel can be observed,which proved that keratin has been successfully grafted with A6 ACA.Secondly,the keratin-A6 ACA composite microspheres coated with IR783 fluorescent dye were prepared by the O/W/O method for imaging observation of the damage area.In vivo and in vitro experiments confirmed that IR783 would quench the fluorescence under acidic conditions,while the composite microspheres have the function of protecting the fluorescence effect under acidic conditions,indicating that the adhesion of microspheres on the injured area also has the effect of isolating gastric acid and promoting the repair of the injured area.Keratin and A6 ACA composite microspheres also have the functions of acid resistance,gathering in damaged areas and repair of damaged ulcer tissues,showing excellent potential for treating gastric ulcers.(2)The IR783-embedded keratin-A6 ACA composite microspheres were gavaged into gastric ulcer mice and normal mice with varying degrees of injury to investigate its role in the diagnosis of gastric ulcer damage.The experiment found that composite microspheres can be quickly cleared in gastric ulcer mice,and no fluorescence was found in the stomach for 4 hours.In mice with gastric ulcer,the adhesion ability of the composite microspheres is stronger.After 4 hours,fluorescence can be observed in the stomach with ulcer lesions,and the fluorescence intensity increased with the increase of the ulcer area.The fluorescent area in the gastric tissue of mice with large area gastric ulcer(3755±388)was 3 times that of mice with small area gastric ulcer(1189±143),which proved that the keratin-A6 ACA composite microspheres are easier to firmly adhered to damaged gastric tissue parts,showing a good function of diagnosing the degree of damage.(3)A mouse model of gastric ulcer induced by ethanol was treated with keratin,A6 ACA,keratin-A6 ACA composite microspheres and potassium bismuth citrate(positive drug control).Since the degree of gastric ulcer repair is positively correlated with the treatment time,the treatment effect of each group of drugs on gastric ulcer was evaluated by gross examination of gastric mucosal hemorrhagic lesions,histopathological section observation,oxidative stress detection and serum inflammatory factor expression at different time points(24h,48 h and 72h).As the experimental results showed that after 72 hours treatment with keratin-A6 ACA composite microspheres,the ulcer area was reduced by 71%,,while the ulcer area in the control group without drug treatment reduced by 32%.;SOD activity of keratin-A6 ACA composite microspheres group were increased by 150%,and the release of MDA and MPO were decreased by 84% and 88%,respectively.Keratin-A6 ACA composite microspheres also reduced serum TNF-α,IL-6 and IL-1βlevels by 50%,75% and 69%,respectively.All the treatment effects of keratin-A6 ACA composite microspheres were close to those of the positive control group.The overall results showed that Keratin-A6 ACA composite microspheres promote gastric mucosal repair by protecting the enzymatic antioxidant superoxide dismutase(SOD),inhibiting lipid peroxidation(MDA and MPO).Compared with keratin,A6 ACA and positive drug group,keratin-A6 ACA composite microspheres has better treatment effect of gastric ulcer.The keratin-A6 ACA composite microspheres embedded with IR783 have excellent fluorescence localization,enrichment in the injured area,resistance to gastric acidity and repair of damaged gastric tissue,showing a significantly stronger therapeutic effect on gastric ulcer than keratin and A6 ACA alone.In short,the keratin-A6 ACA hydrogel composite microspheres are a material with good repair ability for gastric ulcer,which conforms to the effectiveness principles of clinical medical materials. |
PDF Full Text Request