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This study aims to prepare and evaluate a skin patch containing mesoporous silica nanoparticles with doxycycline for skin wound healing in a rat model. For this purpose, 84 female rats were randomly placed in four equal groups: (A) Control group with only skin defects and no therapeutic intervention; (B) Chitosan group in which a chitosan skin patch without loading any drug was placed on their skin defect; (C); The ChMesN group had a chitosan skin patch containing drug-free mesoporous silica nanoparticles; (D) ChMesND group had a skin patch loaded with doxycycline loaded with mesoporous silica nanoparticles on their skin defect. The histological results showed that on the 3rd day of the study, collagen fiber orientation was significantly higher in the ChMesND group than in the other groups. On the 7th day of the study, neovascularization, and inflammation in the ChMesND group were significantly higher and lower than in the other groups, respectively. On day 21, the most re-epithelialization was observed in the ChMesND group. It was found that on day 7, the wound area in the ChMesND group was significantly less than in other groups. On the 21st day of the study, the minimal experimental wound area was related to chitosan and ChMesND groups. Although chitosan has anti-inflammatory effects, its combination with doxycycline with several beneficial biological effects can have significant therapeutic effects with chitosan. Hence, it can be concluded that chitosan skin patch containing doxycycline can be suitable dressings for managing and accelerating the healing of skin wounds., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Aims: A controlled release drug delivery system loaded with buprenorphine and ketorolac was synthesized and used in the experimental model of bone defect and while evaluating the inflammatory response, the repair process in the defects was investigated. Materials and methods: To determine the effectiveness of the synthesized the mentioned systems, 5 groups were defined; the control group, the chitosan hydrogel receiving group (chitosan group), the ketorolac-loaded chitosan hydrogel group (ketorolac group), the buprenorphine-loaded chitosan hydrogel receiving group (buprenorphine group), and the chitosan hydrogel-loading group loaded with a combination of ketorolac and buprenorphine (ketorolac-buprenorphine group). Results: The results showed that the population of leukocytes (tWBC) and neutrophils on different days of the study in the control group compared to other groups had a significant increase ( P < 0.05) while on day 7 of the study in the ketorolac group these parameters decreased significantly compared to other groups ( P < 0.05). While examining the histological changes in the experimental defect created in the proximal tibia of rats at different times, some inflammatory indices such as total and differential leukocyte population, plasma concentrations of TNF-α and IL-6 were compared in different groups ( P < 0.05). The various evaluated data showed that among the different groups, in the control and ketorolac-buprenorphine groups, there was the lowest and highest control of inflammatory response and bone repair, respectively. Conclusion: In the ketorolac group due to the impact of ketorolac on leukocyte populations the best bone healing can be expected among the different treatment groups.

Nowadays, the development of drug-loaded electrospun organic-inorganic composite scaffolds for tissue engineering application is an attractive approach. In this study, a composite scaffold of Poly-l-lactic acid (PLLA) incorporated dexamethasone (Dexa) loaded Mesoporous Silica Nanoparticles (MSN) coated with Chitosan (CS) were fabricated by electrospinning for bone tissue engineering application. The MSN was prepared by precipitation method. After that, Dexamethasone (Dexa) was loaded into MSNs (MSN-Dexa). In the following, CS was coated over the prepared nanoparticles to form MSN-Dexa@CS and then, were mixed to PLLA solution to form MSN-Dexa@CS/PLLA composite for electrospinning. The surface morphology, hydrophilicity, tensile strength and the bioactivity of the scaffolds were characterized. The osteogenic proliferation and differentiation potential were evaluated by MTT assay and by measuring the basic osteogenic markers: the activity of the enzyme alkaline phosphatase and the level of calcium deposition. The composite scaffolds prepared here have conductive surface property and have a better osteogenic potential than pure PLLA scaffolds. Hence, the controlled release of nanoparticle containing Dexa from composite scaffold supported the osteogenesis and made the composite scaffolds ideal candidates for bone tissue engineering application and pH-sensitive delivery of drugs at the site of implantation in tissue regeneration.

Background: In the present study, the effectiveness of a controlled-release drug delivery system of chitosan hydrogel loaded with ketorolac and buprenorphine on oxidative stress indices and albumin changes in the experimental bone defect model was considered. Methods: After creating an experimental defect in the right tibia of each rat, 5 groups, including (A) the control group that did not receive any pharmacological intervention, (B) the chitosan hydrogel receiving group, (C) the group receiving chitosan hydrogel loaded with buprenorphine, (D) the group receiving chitosan hydrogel loaded with ketorolac, and (E) the group receiving chitosan hydrogel loaded with ketorolac and buprenorphine, were considered. Serum concentrations of antioxidant factors and albumin levels were then measured on days 0, 3, 7, and 21 after surgery. Results: In the control group, the maximum amount of oxidative stress and the maximum activity of antioxidant enzymes on the third and seventh days were compared between the 4 treatment groups. Moreover, the maximum amount of albumin on the third day was recorded and compared between the 4 other treatment groups. In 4 treatment groups, a significant decrease was observed in the mean of parameters related to oxidative stress compared to the control group, which was more noticeable in the group receiving ketorolac. Conclusion: In the present study, the highest rate of control of oxidative stress conditions was observed in the group treated with the ketorolac-loaded chitosan hydrogel system, possibly due to its antioxidant properties and better control of inflammatory conditions caused by the use of chitosan and ketorolac in this treatment group. [ABSTRACT FROM AUTHOR]

The present study aimed to prepare and evaluate a controlled-release system based on a chitosan scaffold containing selenium nanoparticles loaded with doxycycline. Its topical application in skin wound healing in rats was investigated. Therefore, 80 female rats were used and, after creating experimental skin defects on their back, were randomly divided into four equal groups: the control group without any therapeutic intervention; the second group received a chitosan transdermal patch (Ch); the third group received chitosan transdermal patch loaded with selenium nanoparticles (ChSeN), and the last group received chitosan transdermal patch containing selenium nanoparticle loaded by doxycycline (ChSeND). Morphological and structural characteristics of the synthesized patches were evaluated, and in addition to measuring the skin wound area on days 3, 7, and 21, a histopathological examination was performed. On the third day of the study, less hemorrhage and inflammation and more neo-vascularization were seen in the ChSeND group. Moreover, on day 7, less inflammation and collagen formation were recorded in the ChSeN and ChSeND groups than in the other groups. At the same time, more neo-vascularization and re-epithelialization were seen in the ChSeND group on days 7 and 21. In addition, on day 21 of the study, the most collagen formation was in this group. Examination of the wound area also showed that the lowest area belonged to the ChSeND group. The results showed that the simultaneous presence of selenium nanoparticles and doxycycline in the ChSeND group provided the best repair compared to the control, Ch and ChSeN groups. [ABSTRACT FROM AUTHOR]