Octenidine dihydrochloride exposure decreased cell viability and proliferation in a dose-dependent manner in primary adult human normal articular chondrocytes
Exposure to octenidine dihydrochloride for 30 seconds resulted in macroscopic morphological changes, decreased viability, and proliferation of primary adult human normal articular chondrocytes in a dose-dependent manner when octenidine dihydrochloride concentration was titrated from 0.003125–0.1% (Figs. 1, 2, and 3). Primary adult human normal articular chondrocytes did not differ morphologically from control cells when treated with octenidine dihydrochloride at 0.001562% and 0.003125%. Cells acquired a rounded, ruffled cell morphology at the higher doses of 0.00625%, 0.0125%, 0.025%, 0.05%, and 0.1% octenidine dihydrochloride (Fig. 1).
The cell viability monitored by trypan blue assay staining after treatment with octenidine dihydrochloride at 0.001562%, 0.003125%, 0.00625%, 0.0125%, 0.025%, 0.05%, and 0.1% showed the results as 87.5 ± 1.8%, 65.2 ± 1.9%, 50.8 ± 1.3%, 43.7 ± 4%, 39.8 ± 1.2%, 36.5 ± 2.7%, and 27.1 ± 1.9%, respectively. The cell viability of octenidine dihydrochloride treatment groups was significantly lower than the control groups to all concentrations starting from 0.001562% (P < 0.001, respectively) (Fig. 2). Cell viability as monitored by the WST-1 assay after identical treatment with graded concentrations of octenidine dihydrochloride was 87.1 ± 0.4%, 61.5 ± 2.3%, 48.0 ± 1.2%, 40.33 ± 1.6%, 38.4 ± 1.4%, 36.0 ± 0.4%, and 29.2 ± 1.0%, respectively. The cell viability of octenidine dihydrochloride treatment groups was significantly lower than the control groups to all concentrations starting from 0.001562% (P < 0.001, respectively) (Fig. 2).
Analysis of cell proliferation revealed decreased proliferative indices upon treatment with octenidine dihydrochloride at 0.001562%, 0.003125%, 0.00625%, 0.0125%, 0.025%, 0.05%, and 0.1% (up to 3.4-fold decrease; P < 0.001 at all concentrations compared with the control group) (Fig. 2). The half-maximal inhibitory concentration (IC50), reflecting the dose of octenidine dihydrochloride at which approximately 50% of the cells were alive, was 0.01047% (Table 1).
Table 1
Half maximal inhibitory concentration (IC50) values of octenidine dihydrochloride and chlorhexidine gluconate.
| Octenidine dihydrochloride | Chlorhexidine gluconate |
IC50 | 0.01047% | 0.06014% |
Chlorhexidine gluconate exposure decreased cell viability and proliferation in a dose-dependent manner in primary adult human normal articular chondrocytes
Identical exposure to chlorhexidine gluconate for 30 seconds resulted in macroscopic morphological changes, decreased viability and proliferation of primary adult human normal articular chondrocytes in a dose-dependent manner when chlorhexidine gluconate concentration was titrated from 0.003125–0.1% (Figs. 4, 5, and 6). Primary adult human normal articular chondrocytes did not differ morphologically from control cells when treated with chlorhexidine gluconate at 0.003125%, 0.00625%, and 0.0125%. However, cells acquired a rounded, ruffled cell morphology at the higher doses of 0.025%, 0.05%, 0.1%, and 0.2% chlorhexidine gluconate (Fig. 4).
The cell viability monitored by trypan blue assay staining after treatment with chlorhexidine gluconate at 0.003125%, 0.00625%, 0.0125%, 0.025%, 0.05%, 0.1%, and 0.2% showed the results as 95.1 ± 1.1%, 90.3 ± 1.8%, 87.5 ± 2.1%, 62.9 ± 1.5%, 43.2 ± 3.4%, 39.7 ± 1.9%, and 34.5 ± 0.8%, respectively. The cell viability of chlorhexidine gluconate treatment groups was significantly lower than the control groups to all concentrations starting from 0.00625% (P < 0.001, respectively) (Fig. 5). There was no significant difference between the chlorhexidine gluconate treatment group at 0.003125% and the control group (P > 0.09) (Fig. 5). Cell viability as monitored by WST-1 assay after identical treatment with graded concentrations of chlorhexidine gluconate was 93.64 ± 1.3%, 90.8 ± 0.5%, 85.2 ± 1.1%, 64.7 ± 2.3%, 44.7 ± 3.0%, 38.9 ± 1.3%, and 34.5 ± 1.7%, respectively. The cell viability of chlorhexidine gluconate treatment groups was significantly lower than the control groups to all concentrations starting from 0.003125% (P < 0.001, respectively) (Fig. 5).
Analysis of cell proliferation revealed decreased proliferative indices upon treatment with chlorhexidine gluconate at 0.00625%, 0.0125%, 0.025%, 0.05%, 0.1%, and 0.2% (up to 2.9-fold decrease; P < 0.001 at all concentrations compared with the control group) (Fig. 5). There was no significant difference between the chlorhexidine gluconate treatment group at 0.003125% and the control group (P > 0.06) (Fig. 5). The half-maximal inhibitory concentration (IC50) of chlorhexidine gluconate was 0.06014% (Table 1).
Octenidine dihydrochloride and chlorhexidine gluconate exposure decreased cell viability in human articular cartilage explant cultures
Exposure of human articular cartilage explants to 0.1% octenidine dihydrochloride for 30 seconds resulted in a considerably decreased viability of adult human articular chondrocytes within the human cartilage cultures compared with control explant cultures (Fig. 7). Likewise, exposure to 0.1% chlorhexidine gluconate for 30 seconds resulted in decreased viability of adult human articular chondrocytes within human articular cartilage explant cultures compared with control explant cultures (Fig. 7).