Electrical stimulation therapy and rotary jet-spinning scaffold to treat bone defects.

The combination of electrical stimulation (ES) and bone tissue engineering (BTE) has been successful in treatments of bone regeneration. This study evaluated the effects of ES combined with PCL + ß-TCP 5% scaffolds obtained by rotary jet spinning (RJS) in the regeneration of bone defects in the calvaria of Wistar rats. We used 120 animals with induced bone defects divided into 4 groups (n = 30): (C) without treatment; (S) with PCL+ ß-TCP 5% scaffold; (ES) treated with ES (10 µA/5 min); (ES + S) with PCL + ß-TCP 5% scaffold. The ES occurred twice a week during the entire experimental period. Cell viability (in vitro: Days 3 and 7) and histomorphometric, histochemical, and immunohistochemical (in vivo; Days 30, 60, and 90) analysis were performed. In vitro, ES + S increased cell viability after Day 7 of incubation. In vivo, it was observed modulation of inflammatory cells in ES therapy, which also promoted blood vessels proliferation, and increase of collagen. Moreover, ES therapy played a role in osteogenesis by decreasing ligand kappa B nuclear factor-TNFSF11 (RANKL), increasing alkaline phosphatase (ALP), and decreasing the tartarate-resistant acid phosphatase. The combination of ES with RJS scaffolds may be a promising strategy for bone defects regeneration, since the therapy controlled inflammation, favored blood vessels proliferation, and osteogenesis, which are important processes in bone remodeling.

Anti-inflammatory and antioxidant properties of Alternanthera brasiliana improve cutaneous wound healing in rats.

Alternanthera brasiliana (L.) Kuntze is recognized for its healing properties; however, its therapeutic effects remain unclear. Therefore, our study aimed to elucidate the wound healing activities of A. brasiliana using in vitro and in vivo assays. In vitro assays were used to evaluate the antibacterial, anti-inflammatory, and antioxidant effects of A. brasiliana extract. For the in vivo study, two dorsal excisions were established in Wistar rats using a punch (1.5 cm in diameter), which were topically treated daily with 2% carbopol gel (Ctrl group) or 20% hydroalcoholic plant extract with 2% carbopol gel (A. brasiliana-Ab group). After the 2nd, 7th, 14th, and 21st days, inflammation, oxidative damage, antioxidants, angiogenesis, tissue formation, and re-epithelialization were evaluated. In vitro, Ab reduced nitric oxide, anion superoxide, and pro-inflammatory cytokine production. In vivo, Ab presented lower levels of inflammatory infiltrate, although increased levels of IL-1ß and TGF-ß1 were observed. The plant extract controlled oxidative damage by antioxidants, which favored angiogenesis, collagenesis, and wound re-epithelialization. Thus, the topical application of the hydroalcoholic extract of 20% A. brasiliana was distinguished by its important anti-inflammatory and antioxidant activities both in vivo and in vitro. The plant extract also stimulated angiogenesis and tissue formation, accelerating total re-epithelization, which is promising for wound healing.

Electrical therapies act on the Ca2+ /CaM signaling pathway to enhance bone regeneration with bioactive glass [S53P4] and allogeneic grafts.

This study aimed to investigate the application of low-intensity electrostimulation (ES) and electromagnetic stimulation (EM) associated with bioactive glass (BG) or allogeneic grafts (BB) in bone regeneration. A cell viability test on osteoblasts (UMR-106) was performed in the presence of BB and BG grafts associated with ES (10 µA/5 min) and EM (500 Hz/2 min). Critical defects (25 mm2 ) in calvaria were generated in male Wistar rats, and bone regeneration was evaluated on the 30th, 60th, and 120th days after surgery. Cell proliferation increased with the application of ES in both grafts and after EM with BG. Bone remodeling was more effective using the allogeneic graft in both therapies, with increased angiogenesis, osteoblast proliferation, and OPN expression in the BB + EM group. A higher number of osteoblasts and osteoclasts, and an increase in bone sialoprotein, Runx-2, and Opn gene expression were found in the BB + ES group. The BG graft associated with EM therapy had an increased proliferation of osteoblasts and increased expression of Runx-2 and Opn. Groups that had BG and ES therapy had increased numbers of osteoblasts, osteoclasts, and increased OPN expression. The expression of voltage-gated calcium channels increased in groups with ES, while calmodulin expression increased in therapies without grafting. ES and EM therapies favored the repair of bone defects upon grafting by improving angiogenesis, osteogenic gene expression, and tissue reorganization. Despite activating different pathways, both therapies increased the intracellular concentrations of calmodulin, leading to cell proliferation and bone regeneration.

Do electrical current and laser therapies improve bone remodeling during an orthodontic treatment with corticotomy?

OBJECTIVES: Evaluate the bone remodeling during orthodontic movement with corticotomy when submitted to low-intensity electrical stimulation application (microcurrent-MC) and low-level laser therapy (LLLT). MATERIAL AND METHODS: One hundred and fifty Wistar rats were divided into the following 5 groups: (C) submitted to tooth movement; (Cort) tooth movement/corticotomy; (Cort-L) tooth movement/corticotomy/laser AsGaAl 808 nm (4.96J/50s); (Cort-Mc) tooth movement/corticotomy/microcurrent (10 µA/5 min); (Cort-L-Mc) tooth movement/corticotomy and laser/microcurrent alternated. Inflammation, angiogenesis, and osteogenesis were evaluated in the periodontal ligament (PDL) and alveolar bone on the 7th, 14th, and 21st days of orthodontic movement. RESULTS: The quantification of inflammatory infiltrate, angiogenesis and expression of TGF-ß1, VEGF, and collagen type I were favorably modulated by the application of therapies such as low-level laser therapy (LLLT), MC, or both combined. However, electrical stimulation increased fibroblasts, osteoclasts and RANK numbers, birefringent collagen fiber organization, and BMP-7 and IL-6 expression. CONCLUSIONS: Low-level laser therapy (LLLT) and MC application both improved the process of bone remodeling during orthodontic treatment with corticotomy. Still, electrical current therapy promoted a more effective tooth displacement but presented expected root resorption similar to all experimental treatments. CLINICAL RELEVANCE: It is important to know the effects of minimally invasive therapies on cellular and molecular elements involved in the bone remodeling of orthodontic treatment associated with corticotomy surgery, in order to reduce the adverse effects in the use of this technique and to establish a safer clinical routine.

Electrical stimulation: Complementary therapy to improve the performance of grafts in bone defects?

The limitations of bone reconstruction techniques have stimulated the tissue engineering for the repair of large bone defects using osteoconductive materials and osteoinductive agents. This study evaluated the effects of low intensity electric current on the inorganic bovine graft in calvaria defects. Bone defects were performed with piezoelectric system in the calvaria of Wistar rats divided into four groups (n = 24): (C) without grafting and without electrical stimulation; (E) with grafting; (MC) without grafting and submitted to electrical stimulation; (MC + E) with grafting and submitted to electrical stimulation. Inflammatory, angiogenic and osteogenic events during bone repair at the 10th, 30th, 60th, and 90th days were considered. Several inflammatory markers demonstrated the efficacy of grafting in reducing inflammation, particularly when subjected to electrical stimulation. Angiogenesis and collagen organization were more evident by electrical stimulation application on the grafts. Moreover, the osteogenic cell differentiation process indicated that the application of microcurrent on grafting modulated the homeostasis of bone remodeling. It is concluded that microcurrent favored the performance of grafts in calvarial rat model. Low-intensity electrical current might improve the osteoconductive property of grafting in bone defects. Therefore, electrical current becomes an option as complementary therapy in clinical trials involving bone surgeries and injuries. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 924-932, 2019.