OBJECTIVETo study the changes of nitric oxide (NO) in the BALB/c hairless mice skin after trichloroethylene (TCE) irritation and the protection of ginkgo biloba extract (GbE) and vitamin E (VE).

METHODS132 BALB/c hairless mice were randomly divided into blank control group, solvent group (olive oil), TCE groups (20%TCE, 40%TCE, 80%TCE and 100%TCE), GbE groups (0.1%GbE, 1%GbE and 10%GbE) and VE groups (5%VE, 10% VE and 20% VE), with 11 animals in each group, 5 for acute irritation test and 6 for the cumulative irritation test. The skin irritation was observed, and the levels of NO in the dorsal skin of BALB/C hairless mice were detected. The kit of NO was used to detect the levels of NO in the dorsal skin of BALB/c hairless mice.

RESULTS(1) The skin presented erythema and edema after TCE irritation both in acute irritation and cumulative irritation test and the skin inflammation showed time-dose effect relationship; the mice skin was protected in GbE or VE groups. (2) In the acute stimulation test, the levels of NO in 80%TCE group (69.895 +/- 9.605 micromol/mg pro) and 100%TCE group (77.273 +/- 9.290 micromol/mg pro) were significantly different compared with blank control group and solvent control group (P < 0.05 or P < 0.01). In the protection group, the NO level were reduced, with the statistically significant differences. (3) In acute irritation test, the levels of NO in 80%TCE group (60.362 +/- 9.817 micromol/mg pro) and 100%TCE group (68.027 +/- 9.354 micromol/mg pro) were significantly different compared with blank control group and solvent control group, (P < 0.05 or P < 0.01); In the protection group, 1% GbE, 10% GbE, 10% VE and 20%VE could reduce the levels of NO, with statistically significant differences.

CONCLUSIONTCE can produce the irritation on the dorsal skin of BALB/c hairless mice and induce the significant increase of the NO levels. GbE and VE can protect the skin from TCE irritation damage.