Chitosan and chitosan/turmeric-based membranes for wound healing: Production, characterization and application.

In the present study, chitosan and chitosan/turmeric-based membranes were produced, characterized and applied in in vivo experiments showing the applicability for skin wound repair. Chitosan 1 % (w/v), chitosan + glycerol 30 % (w/w) and chitosan + glycerol 30 % + turmeric 1.5 % (w/w) membranes were produced through the casting technique. Self-sustainable, homogeneous, and flexible membranes were obtained from all materials tested. The FTIR spectra showed the main vibrational bands for materials used in the chemical groups. The membranes containing glycerol are more flexible than those formed with pure chitosan. Membranes formed with glycerol and glycerol/turmeric are more hydrophilic compared to the membranes formed by pure chitosan. The in vivo results showed that the group who received the chi/gly/turmeric membrane had a statistically greater reduction in the injured area, as well as a better healing process in the histological analysis compared to the other experimental groups. The material developed here is from a natural source, low cost and easy to apply and can accelerate the process of repairing skin lesions.

Treatment of partial injury of the calcaneus tendon with heterologous fibrin biopolymer and/or photobiomodulation in rats.

The present study aimed to evaluate the new heterologous fibrin biopolymer associated, or not, with photobiomodulation therapy for application in tendon injuries, considered a serious and common orthopedic problem. Thus, 84 Rattus norvegicus had partial transection of the calcaneus tendon (PTCT) and were randomly divided into: control (CG); heterologous fibrin biopolymer (HFB); photobiomodulation (PBM); heterologous fibrin biopolymer + photobiomodulation (HFB + PBM). The animals received HFB immediately after PTCT, while PBM (660 nm, 40 mW, 0.23 J) started 24 h post injury and followed every 24 h for 7, 14, and 21 days. The results of the edema volume showed that after 24 h of PTCT, there was no statistical difference among the groups. After 7, 14, and 21 days, it was observed that the treatment groups were effective in reducing edema when compared to the control. The HFB had the highest edema volume reduction after 21 days of treatment. The treatment groups did not induce tissue necrosis or infections on the histopathological analysis. Tenocyte proliferation, granulation tissue, and collagen formation were observed in the PTCT area in the HFB and HFB + PBM groups, which culminated a better repair process when compared to the CG in the 3 experimental periods. Interestingly, the PBM group revealed, in histological analysis, major tendon injury after 7 days; however, in the periods of 14 and 21 days, the PBM had a better repair process compared to the CG. In the quantification of collagen, there was no statistical difference between the groups in the 3 experimental periods. The findings suggest that the HFB and PBM treatments, isolated or associated, were effective in reducing the volume of the edema, stimulating the repair process. However, the use of HFB alone was more effective in promoting the tendon repair process. Thus, the present study consolidates previous studies of tendon repair with this new HFB. Future clinical trials will be needed to validate this proposal.

Polyurethane derived from castor oil monoacylglyceride (Ricinus communis) for bone defects reconstruction: characterization and in vivo testing.

Biomaterials used in tissue regeneration processes represent a promising option for the versatility of its physical and chemical characteristics, allowing for assisting or speeding up the repair process stages. This research has characterized a polyurethane produced from castor oil monoacylglyceride (Ricinus communis L) and tested its effect on reconstructing bone defects in rat calvaria, comparing it with commercial castor oil polyurethane. The characterizations of the synthesized polyurethane have been performed by spectroscopy in the infrared region with Fourier transform (FTIR); thermogravimetric analysis (TG/DTG); X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). For the in vivo test, 24 animals have been used, divided into 3 groups: untreated group (UG); control group treated with Poliquil® castor polyurethane (PCP) and another group treated with castor polyurethane from the Federal University of Piauí - UFPI (CPU). Sixteen weeks after surgery, samples of the defects were collected for histological and histomorphometric analysis. FTIR analysis has shown the formation of monoacylglyceride and polyurethane. TG and DTG have indicated thermal stability of around 125 °C. XRD has determined the semi-crystallinity of the material. The polyurethane SEM has shown a smooth morphology with areas of recesses. Histological and histomorphometric analyzes have indicated that neither CPU nor PCP induced a significant inflammatory process, and CPU has shown, statistically, better performance in bone formation. The data obtained shows that CPU can be used in the future for bone reconstruction in the medical field.

Acetylcholinesterase inhibition prevents alterations in cardiovascular autonomic control and gastric motility in L-NAME-induced hypertensive rats.

AIMS: Autonomic dysfunction in arterial hypertension affects cardiorespiratory control and gastric motility and has been characterized by increased sympathetic and reduced parasympathetic activity. In the present work we investigated the effects of anticholinesterase drugs [donepezil (DON) or pyridostigmine (PYR)] on cardiovascular, autonomic, and gastric parameters in L-NAME-induced hypertensive rats. MATERIALS AND METHODS: Daily oral gavage of L-NAME (70 mg/kg/day) was performed over 14 days in male Wistar rats (180-220 g), whereas daily oral gavage of DON or PYR (1.6 and 22 mg/kg/day, respectively) started 2 days after the L-NAME treatment initiation and lasted 12 days. The development of hypertension was verified by tail plethysmography technique. After the end of treatments, the animals were subjected to experimental protocols (6-12 animals per group; total number of animals used: 78). KEY FINDINGS: L-NAME hypertensive animals had no alterations in heart rate (HR) and intrinsic HR, but showed reduction in baroreflex sensitivity, parasympathetic tone, and gastric motility; and the sympathetic tone, chemoreflex sensitivity, and the LF (low frequency) band of systolic arterial pressure (SAP) variability were increased. DON or PYR attenuated the increase in mean arterial pressure (MAP) induced by L-NAME. Both anticholinesterase drugs were effective in preventing the decrease in baroreflex sensitivity, parasympathetic tone and gastric motility, and also prevented the increases in peripheral chemoreflex response and cardiac sympathetic tone. SIGNIFICANCE: Acetylcholinesterase inhibition with DON or PYR is a promising pharmacological approach to increase parasympathetic function, thus preventing the hypertension-induced alterations in the cardiovascular, gastrointestinal and autonomic systems.

Evaluation of bone repair after application of a norbixin membrane scaffold with and without laser photobiomodulation (λ 780 nm).

Biocompatible membranes are widely used in medicine to stimulate bone repair. Several studies have demonstrated that laser photobiomodulation (PBM) also stimulates osteoblast proliferation and osteogenesis at the fracture site, leading to a greater deposition of bone mass and accelerating the process of bone consolidation. This work assessed the therapeutic effect of 780-nm laser PBM and a polystyrene membrane coated with norbixin and collagen (PSNC) on bone healing in rats with calvarial bone defect. Histological staining, Raman spectroscopy, and scanning electron microscopy (SEM) were used to evaluate the bone repair process. Four experimental treatment groups were compared: C, control; M, membrane only; L, laser PBM only; and ML, membrane + laser PBM. A bone defect was created in the calvaria of each animal, with each group subdivided into two subgroups that underwent euthanasia after 15 and 30 days treatment. The L and ML groups were irradiated (λ = 780 nm, ED = 6 J/cm2, P = 60 mW, t = 4 s) postoperatively on alternate days until they were euthanized. The bone concentration of hydroxyapatite (CHA) showed a clear gradation with increasing phosphate area in the order B (normal cortical bone) > L > M > ML > C for both periods. The PSNC membrane was effective in reducing the inflammatory process and served as a scaffold for bone repair. The laser PBM also showed positive effects on the bone repair process with increased deposition and organization of the newly formed bone. However, laser PBM failed to improve the bioactive properties of the membrane scaffold.

Low-intensity LED therapy (658 nm) on burn healing: a series of cases.

The objective of this study was to evaluate the effects of LED on burns healing. Five patients with skin burns were submitted to photobiomodulation by LED, GaAsIP diode, (λ 658 nm) with 40 mW, 7 J/cm2 on every other day. Biopsies of burned skin were performed and the healing process was photographed. Patients with bilateral burns were used as self-control, having one limb being irradiated and the contralateral limb irradiated with placebo. The burns treated with LED showed higher epithelization, with keratinocytes and fibroblasts proliferation, increased collagen synthesis, decreased pain, and pruritus. In conclusion, there was a faster clinical improvement in the irradiated limbs.

Digital photogrammetry and histomorphometric assessment of the effect of non-coherent light (light-emitting diode) therapy (λ640 ± 20 nm) on the repair of third-degree burns in rats.

Recent studies have demonstrated the efficacy of coherent light therapy from the red region of the electromagnetic spectrum on the tissue-healing process. This study analysed the effect of non-coherent light therapy (light-emitting diode-LED) with or without silver sulfadiazine (sulpha) on the healing process of third-degree burns. In this study, 72 rats with third-degree burns were randomly divided into six groups (n = 12): Gr1 (control), Gr2 (non-contact LED), Gr3 (contact LED), Gr4 (sulfadiazine), Gr5 (sulfadiazine + non-contact LED) and Gr6 (sulfadiazine + contact LED). The groups treated with LED therapy received treatment every 48 h (λ = 640 ± 20 nm, 110 mW, 16 J/cm(2); 41 s with contact and 680 s without contact). The digital photometric and histomorphometric analyses were conducted after the burn occurred. The combination of sulpha and LED (contact or non-contact) improved the healing of burn wounds. These results demonstrate that the combination of silver sulfadiazine with LED therapy (λ = 640 ± 20 nm, 4 J/cm(2), without contact) improves healing of third-degree burn wounds, significantly reduces the lesion area and increases the granulation tissue, increases the number of fibroblasts, promotes collagen synthesis and prevents burn infections by accelerating recovery.