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.

Expression of the glucose transporter HXT1 involves the Ser-Thr protein phosphatase Sit4 in Saccharomyces cerevisiae.

We studied the effect of the loss of the Ser-Thr protein phosphatase Sit4, an important post-translational regulator, on the steady-state levels of the low-affinity glucose transporter Hxt1p and observed a delay in its appearance after high glucose induction, slow growth, and diminished glucose consumption. By analyzing the known essential pathway necessary to induce Hxt1p, we observed a partial inhibition of casein kinase I activity. In both WT and sit4Δ strains, the transcript was induced with no significant difference at 15 min of glucose induction; however, after 45 min, a clear difference in the level of expression was observed being 45% higher in WT than in sit4Δ strain. As at early time of induction, the HXT1 transcript was present but not the protein in the sit4Δ strain we analyzed association of HXT1 with ribosomes, which revealed a significant difference in the association profile; in the mutant strain, the HXT1 transcript associated with a larger set of ribosomal fractions than it did in the WT strain, suggesting also a partial defect in protein synthesis. Overexpression of the translation initiation factor TIF2/eIF4A led to an increase in Hxt1p abundance in the WT strain only. It was concluded that Sit4p ensures that HXT1 transcript is efficiently transcribed and translated thus increasing protein levels of Hxt1p when high glucose levels are present.