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Published on: September 7, 2013
Experimental evaluation of cyadox phototoxicity to Balb/c mouse skin
Qinghua He1, Guijie Fang, Yulian Wang
1National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory of Food Safety Evaluation, Huazhong Agricultural University, Wuhan, Hubei, China.
Background:
Cyadox is a veterinary drug mainly used as an effective antimicrobial promoter in animal husbandry. It was reported that the other quinoxaline-1,4-dioxide compounds had phototoxicity, but only few data are reported on phototoxicity of cyadox. This study was performed to evaluate the phototoxicity of cyadox on skin.
Methods:
Eighty mice were equally divided into eight groups. Five groups with ultraviolet A (UVA) irradiation for 2 h (21 J/cm2) were administered at doses of 0, 10, 50, 200 mg/kg cyadox and 50 mg/kg olaquindox, respectively, and others as controls without irradiation administered at doses of 0, 200 mg/kg cyadox and 50 mg/kg olaquindox, respectively. Drugs were administered by gavage once daily with a suspension in 0.8% carboxymethyl-cellulose for consecutive 4 days. After administration, a recovery period of 7 days was arranged. Histopathological examination of auricular skin was performed on days 5 and 12. Measurement of auricular thickness, gross pathology and erythema score were conducted once daily.
Results:
Cyadox groups (200, 50 and 10 mg/kg) with irradiation had erythema and oedema of auricular skin with dose-response relationship, which gradually convalesced after dosing and irradiation ceased. Severe erythema, oedema and necrosis of auricles were observed on olaquindox group with irradiation.
Conclusion:
The phototoxicity of cyadox was mild and reversible, which demonstrated a good safety profile of cyadox in terms of phototoxicity.
