Figure 1.
Electrical stimulation (ES) had no cytotoxic effect on human skin fibroblasts.
Cells were cultured and subjected to ES at 50 or 200 mV/mm for various periods. Culture supernatants were collected and used to measure LDH activity release, as described in the M & M section. Data are means ± SD, n = 5, with p<0.05 indicating the significant difference versus the control (non-exposed cells).
Figure 2.
Effect of ES on dermal fibroblast viability.
Cells were seeded on the conductive PPy/HE/PLLA membranes and cultured for 24 h, then exposed to ES of 50 or 200 mV/mm for 2, 4, or 6 h, and subsequently cultured for an additional 24 h. The cells were then detached from each membrane and cell viability was ascertained by trypan blue exclusion assay (n = 5). The ES-exposed and non-exposed cultures were compared, with the difference considered significant at p<0.05.
Figure 3.
Effect of ES on dermal fibroblast migration/repair.
Cells were cultured on PPy/HE/PLLA conductive membranes for 24 h, then exposed to ES for 2, 4, or 6 h, followed by a culture without ES for 24 h. The cells were detached from each membrane, seeded in Petri dishes, and cultured up to 100% confluence. Scratches were then made on each monolayer and the medium was refreshed, with the cultures maintained for various time periods prior to observation and determination of the wound recovery. Values are means ± SD (n = 5). The ES-exposed and non-exposed cultures were compared, with the difference considered significant at p<0.05.
Figure 4.
Effect of ES on FGF-1 secretion by the dermal fibroblasts.
Cells were cultured on PPy/HE/PLLA conductive membranes for 24 h, followed by exposure to ES for 2, 4, or 6 h. A medium containing only 1% FBS-supplemented DME was used to culture the cells for 24 h post-exposure to ES. The supernatants were then collected and FGF-1 concentrations in all conditions were quantified by sandwich enzyme-linked immunosorbent assays. Values are means ± SD (n = 5). The ES-exposed and non-exposed cultures were compared, with the difference considered significant at p<0.05.
Figure 5.
Effect of ES on FGF-2 secretion by the dermal fibroblasts.
Cells were cultured on PPy/HE/PLLA conductive membranes for 24 h followed by exposure to ES for 2, 4, or 6 h. A medium containing only 1% FBS-supplemented DME was used to culture the cells for 24 h post-exposure to ES. The supernatants were then collected and FGF-2 concentrations in all conditions were quantified by sandwich enzyme-linked immunosorbent assays. Values are means ± SD (n = 5). The ES-exposed and non-exposed cultures were compared, with the difference considered significant at p<0.05.
Figure 6.
Dermal fibroblasts exposed to 50 mV/mm contracted the collagen gel matrix.
Following exposure to ES, the fibroblasts were added to collagen type I gel and cultured. The diameter of each collagen gel was measured at 48 and 72 h. Representative photos show the action of the ES-exposed and non-exposed cells on collagen gel contraction. The diameters of the collagen gels are presented. Values are means ± SD (n = 5). The ES-exposed and non-exposed cultures were compared, with the difference considered significant at p<0.05.
Figure 7.
Dermal fibroblasts exposed to 200 mV/mm highly contracted the collagen gel matrix.
Following exposure to ES, the fibroblasts were added to a collagen type I gel and cultured. The diameter of each collagen gel was measured at 48 and 72 h. Representative photos show the action of the ES-exposed and non-exposed cells on collagen gel contraction. The diameters of the collagen gels are presented. Values are means ± SD (n = 5). The ES-exposed and non-exposed cultures were compared, with the difference considered significant at p<0.05.
Figure 8.
Effect of ES on fibroblast α-SMA expression.
Dermal fibroblasts were seeded on conductive PPy/HE/PLLA membranes followed by exposure to 50 or 200 mV/mm for various periods. The cells were then detached from the conductive membranes, washed, seeded on coverslips, and cultured up to 70% confluence. The cells were then stained using relevant monoclonal antibodies. Cytoplasmically immunolabelled myofibroblasts are presented.
Figure 9.
The proliferative capacity of fibroblasts was maintained and elevated following exposure to ES for 2, 4, or 6 h.
The cells were then detached and used to investigate their proliferative capacity at longer periods (24, 48, and 72 h) post-exposure to ES. Viability was determined by trypan blue exclusion assay. Values are means ± SD, (n = 6). The ES-exposed and non-exposed cultures were compared, with the difference considered significant at p<0.05.