Aloe vera has long been used as a traditional medicine for inducing wound healing. Gingival fibroblasts (GFs) play an important role in oral wound healing. In this study, we investigated the effects of acemannan, a polysaccharide extracted from Aloe vera gel, on GF proliferation; keratinocyte growth factor-1 (KGF-1), vascular endothelial growth factor (VEGF), and type I collagen production; and oral wound healing in rats. [3H]-Thymidine incorporation assay and ELISA were used. Punch biopsy wounds were created at the hard palate of male Sprague Dawley rats. All treatments (normal saline; 0.1% triamcinolone acetonide; plain 1% Carbopol¨; and Carbopol¨ containing 0.5%, 1%, and 2% acemannan (w/w)) were applied daily. Wounded areas and histological features were observed at day 7 after treatment. From our studies, acemannan at concentrations of 2, 4, 8, and 16 mg/ml significantly induced cell proliferation (P<0.05). Acemannan concentrations between 2 – 16 mg/ml significantly stimulated KGF-1, VEGF, and type I collagen expressions (P<0.05). Wound healing of animals receiving Carbopol¨ containing 0.5% acemannan (w/w) was significantly better than that of the other groups (P<0.05). These findings suggest that acemannan plays a significant role in the oral wound healing process via the induction of fibroblast proliferation and stimulation of KGF-1, VEGF, and type I collagen expressions.

This study investigated the effect of acemannan (Aloe vera gel polysaccharide) on dentin formation. Primary human dental pulp cells were treated with acemannan. New DNA synthesis, bone morphogenetic protein-2, alkaline phosphatase activity, dentin sialoprotein expression, and mineralization were determined by [³H]-thymidine incorporation, enzyme-linked immunosorbent assay, biochemical assay, western blotting, and Alizarin Red staining, respectively. Then the upper first molars of 24 male Sprague Dawley rats were intentionally exposed and capped with either acemannan or calcium hydroxide. At day 28, the teeth were histopathologically examined and evaluated for the degree of inflammation, dentin bridge formation, and pulp tissue organization. The results revealed that acemannan significantly increased pulp cell proliferation, bone morphogenetic protein-2, alkaline phosphatase activity, dentin sialoprotein expression, and mineralization, compared with the untreated group. The acemannan-treated group also exhibited a complete homogeneous calcified dentin bridge and good pulp tissue organization, whereas neither was detected in the calcium hydroxide-treated and sham groups. In the acemannan-treated group, either mild or no inflammation was found, whereas the other groups had various degrees of inflammation. The data suggest that acemannan promotes dentin formation by stimulating primary human dental pulp cell proliferation, differentiation, extracellular matrix formation, and mineralization. Acemannan also has pulpal biocompatibility and promotes soft tissue organization.

MMP-9 or Gelatinase B, a member of the matrix metalloproteinase family (MMPs), plays important roles in physiological events such as tissue remodeling and in pathological processes that lead to destructive bone diseases, including osteoarthritis and periodontitis. In addition to its effect on the increase of total bone mass, statin (an HMG-CoA reductase inhibitor) suppresses the expression of MMPs. In this study, we proposed that simvastatin reduces MMP-9 expression in osteoblasts and HT1080 fibrosarcoma cell line. Gelatin zymography, Western blot analysis and reverse transcriptase-PCR were used to investigate the effects of simvastatin on MMP-9 in primary calvaria cells, U2-OS osteosarcoma cells, and HT1080 fibrosarcoma cells. The results from gelatin zymography and Western blot analysis revealed that simvastatin suppressed MMP-9 activity in these cells in concentration- and time-dependent manners. The effective concentrations of simvastatin were 100 – 500 nM, 5 – 15 μM, and 2.5 – 10 μM in primary calvaria, U2-OS, and HT1080 cells, respectively. Collectively, these results suggest that simvastatin is a potent drug for inhibition of MMP-9 expression in osteoblastic cells and HT1080 fibrosarcoma cells.