Toxicity of camphorated phenol and camphorated parachlorophenol in dental pulp cell culture.

The toxicity of phenol, parachlorophenol, camphorated phenol, camphorated parachlorophenol, and camphor was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay on established rat dental pulp cells (RPC-C2A). RPC-C2A cells at the confluent stage were incubated for 24 h in an experimental medium containing each compound at different concentrations. All tested drugs showed cytotoxicity in the MTT assay in a concentration-dependent manner. It is believed that camphor is a vehicle, and it reduces the toxicity of phenol and parachlorophenol. However, camphor itself showed cytotoxicity, and the addition of camphor increased the toxicity of phenol and parachlorophenol, reconfirming the cytotoxicity of these classical antiseptics.

Inhibition of osteoclast-like cell formation by sodium salicylate and indomethacin in mouse bone marrow culture.

The present study examined the effect of sodium salicylate and indomethacin on the recruitment of osteoclast-like cells in vitro. When mouse bone marrow cells were cultured for 8 days with 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25-(OH)2D3, 10(-8) M), prostaglandin E2 (PGE2, 10(-6) M) and recombinant human interleukin-1 alpha (rHIL-1 alpha, 2 ng/ml), numerous tartrate-resistant acid phosphatase (TRAP-positive) multinucleated cells (MNCs) formed. Adding sodium salicylate or indomethacin inhibited the formation of TRAP-positive MNCs in a dose-dependent manner. This inhibitory effect was more pronounced when the drugs were given at a later stage in the culture period. Indomethacin appeared to be more potent than sodium salicylate. PGE2 production was inhibited by sodium salicylate or indomethacin. Exogenous PGE2 failed to overcome the inhibitory effect of both drugs. These results suggest that sodium salicylate and indomethacin have inhibitory effects on the recruitment of osteoclast-like MNCs, preferentially on the later stage, and that PGE2 is not the only compound targeted by these drugs in reducing osteoclast-like cell formation in mouse bone marrow culture.

The effect of sodium salicylate on the osteoclast-like cell formation and bone resorption in a mouse bone marrow culture.

Salicylates are reported to have an inhibitory effect on bone resorption in vivo and in vitro. The present study examined the effect of sodium salicylate on the formation of osteoclast-like cells in vitro. When mouse bone marrow cells were cultured for 8 days with 10(-8) M 1 alpha, 25-dihydroxyvitamin D3 (1 alpha, 25(OH)2D3), numerous clusters of mononuclear and multinucleated cells (MNCs) formed, which stained positive for tartrate-resistant acid phosphatase (TRAP-positive). In similar cultures using sodium salicylate, the number of both TRAP-positive mononuclear and TRAP-positive MNCs were found to diminish in proportion to the concentration of sodium salicylate. A time-course experimental model showed that the number of TRAP-positive MNCs decreased slightly when sodium salicylate was given early in the culture period, and decreased markedly when the drugs were given later in the culture period. Pit formation and bone-resorption area on the bone slices were also inhibited by adding sodium salicylate continuously with 1 alpha, 25(OH)2D3. The sodium salicylate showed no cytotoxic effect because the total number of adherent cells, including both TRAP-positive and TRAP-negative cells, was independent of the presence of sodium salicylate. These results suggest that sodium salicylate has an inhibitory effect on the recruitment of osteoclast-like MNCs and that this inhibition is greater during the later stage of mouse bone marrow culture.