Hydrogels based on galactomannan and κ-carrageenan containing immobilized biomolecules for in vivo thermal-burn wound treatment.

Hydrogels based on natural polysaccharides have demonstrated efficacy in epithelial recovery from cutaneous burn wounds. Here, we prepared a double-network hydrogel consisting of galactomannan (from Cassia grandis seeds) and κ-carrageenan (commercially sourced), cross-linked with CaCl2, as a matrix for immobilizing lactoferrin and/or Cramoll, aiming at its applicability as dressings for second-degree burn wounds. The formulations obtained [H - hydrogel, HL - hydrogel + lactoferrin, HC - hydrogel + Cramoll and HLC - hydrogel + lactoferrin + Cramoll] were analyzed rheologically as well as in terms of their stability (pH, color, microbial contamination) for 90 days. The burn was created with an aluminum bar (97 ± 3 °C) in the dorsal region of Wistar rats and subsequently treated with hydrogels (H, HL, HC, HLC) and control saline solution (S). The burn was monitored for 3, 7 and 14 days to evaluate the efficacy of the hydrogels in promoting wound healing. The hydrogels did not reveal significant pH or microbiological changes; there was an increase in brightness and a reduction in opacity for H. The rheological analysis confirmed the gel-like viscoelastic signature of the systems without substantial modification of the basic rheological characteristics, however HLC proved to be more rigid, due to rheological synergy when combining protein biomolecules. Macroscopic analyses confirmed centripetal healing with wound contraction: S < H < HC < HL < HLC. Histopathological analyses showed that hydrogel-treated groups reduced inflammation, tissue necrosis and fibrosis, while promoting re-epithelialization with focal acanthosis, especially in HLC due to a positive synergistic effect, indicating its potential as a promising therapy in the repair of burns.

Effects including photobiomodulation of galactomannan gel from Cassia grandis seeds in the healing process of second-degree burns.

The epithelium recovery of skin-burned wounds has been currently achieved by several therapies, for example, hydrogel-based dressings and photobiomodulation therapy (PBMT). Thus, this work aimed to evaluate the healing activity of Cassia grandis seeds' galactomannan gel, associated or not with PBMT, in second-degree burns. Sixty male Wistar rats were assigned to four groups: Control (CG), Gel (GG), Laser/PBMT (LG), and Laser+Gel (GLG). Burns were made with an aluminum bar (90 °C), and submitted to clinical observations diary and area measurements at specific days. Microscopic analysis was based on histological criteria. The results showed that GG, LG, and GLG had a higher contraction rate (p < 0.05) than CG on the 14th experimental day, not differing from each other (∼95 %). At 21 days, all groups showed complete contraction (p > 0.05). Considering the histological results, LG and GLG showed excellent pro-wound healing properties after 14 days; at 21 days, all groups showed wound recovery compared to previous days. In view of the macroscopic and microscopic observations, the isolated treatments (Gel or Laser) effectively accelerated healing; however, the association (Laser+Gel) promoted re-epithelialization and stromal remodeling with better evolution of epithelium recovery due to the positive synergistic effect, thus emerging as a promising therapeutic alternative in the repair of burns.

A unique fucosylated chondroitin sulfate type II with strikingly homogeneous and neatly distributed α-fucose branches.

Fucosylated chondroitin sulfates (FCSs) and sulfated fucans (SFs) are conspicuous components of the body wall of sea cucumbers (Holothuroidea). FCSs are composed of a central core of chondroitin sulfate (CS) decorated with branches of mono- or both mono- and disaccharides of α-fucose (FCS types I and II, respectively). FCSs type II have heterogeneous and irregularly distributed α-fucose branches; however, the novel FCS type II from Holothuria lentiginosa described herein via solution nuclear magnetic resonance has strikingly homogeneous α-fucose branches neatly distributed along its CS core. This FCS is built up of three distinct sequential units composed of the typical CS disaccharides of FCSs, rich in ß-galactosamine-4,6diS, decorated with branches of α-Fucp-2,4diS, α-Fucp-3,4diS or α-Fucp[1→3]α-Fucp-4S[1→ linked to the position 3- of the ß-glucuronic acid. Conformational analyses of these repetitive units revealed a fairly rigid structure despite of the high sulfate content of their α-fucose branches. We also determined the structure of the SF from H. lentiginosa as a repetitive tetrasaccharide sequence composed of →3]α-Fucp-2,4diS[1→3]α-Fucp[1→3]α-Fucp-2S[1→3]α-Fucp-2S[1→. Furthermore, we determined that the nonsulfated α-fucose units present in FCS type II did not interfere with their anticoagulant potencies and affinities to calcium. FCS is an autapomorphic molecular character of the class Holothuroidea and the composition of their α-fucose branches differs in a species-specific manner. Branches containing α-Fucp-2,4diS are the most common within the extant holothurians, being found in 90% of the FCSs characterized thus far.

Αlpha-2 Adrenergic and Opioids Receptors Participation in Mice Gastroprotection of Abelmoschus esculentus Lectin.

Lectins are a heterogeneous group of proteins and glycoproteins with potential role as therapeutic and diagnostic tools to combat various diseases, besides some functions on human organism. Abelmoschus esculentus (Okra), a horticultural plant of African origin, is cultivated in northeastern Brazil, and used for different medicinal purposes. This work is aimed to elucidate the action mechanisms of Abelmoschus esculentus lectin (AEL) gastro protective effect on gastropathy induced by ethanol. Fasted mice treated with Ethanol 99.9% (0.2 ml/animal, p.o.) received previously AEL (0.01, 0.1, 1.0, 10 or 50 mg/kg, i.v.), saline (5 ml/kg; i.v.) or ranitidine (80 mg/kg, p.o.) in four experimental series, in which pharmacological tools (yohimbine, naloxone, L-NAME or indomethacin), were administered with the purpose of make clear possible molecular action mechanisms. Mice were euthanized 30 min after ethanol challenge to verify the stomach damages. Establishment of gastric oxidative stress, tissue hemoglobin (Hb) content and microscopic features (H&E) were taken in order to characterize the AEL gastro protective effect. AEL (1 mg/kg) was capable of protect mucosa against ethanol damages in presence of two (L-NAME and indomethacin) of four antagonists/inhibitors used. The AEL effect was reversed by naloxone and yohimbine, showing the involvement of opioids and Αlpha-2 adrenergic receptors on gastric protective effect of this lectin. Evaluation of microscopic features, oxidative stress, and Hb levels pointed the protective effects of AEL. This activity seems to be mediated by alpha-2 adrenergic and opioid receptors activation. Nitric oxide or prostaglandins were not involved. AEL simultaneously showed antioxidant effect that is probably implicated in its intricate defensive mechanism of action.