OBJECTIVETo compare the differences of the efficacy and adverse reaction of Oxaliplatin (L-OHP) treatment to oral squamous cell carcinoma (OSCC) at four different daily time points, and to analyze the characteristics of circadian rhythms.

METHODSSeventy-five nude mice were placed under 12h light and 12h dark cycles. Human OSCC cell line BcaCD885 was inoculated on the cheek of nude mice to establish a nude mice model of OSCC. After 3 weeks, mice were divided into 5 groups (4 experimental groups and 1 control group), with 15 in each group. L-OHP (17 mg x kg(-1)) was injected intravenously at 4 different time points during a period of 24 h, including 4 hours after lights on JHALO), 10 HALO, 16 HALO and 22 HALO for 4 experimental groups. The control group received normal saline of the same volume as that of L-OHP. The efficacy (tumor inhibition rate and survival time) and adverse reaction (body weight, white blood cell and perianal swelling) were observed after administration. The circadian rhythms of the efficacy and adverse reaction were examined by cosine analysis.

RESULTSL-OHP injected at 4, 16 and 22 HALO had great tumor inhibition rates, however, only 16 and 22 HALO groups significantly prolonged survival time of mice. The adverse reactions at 4 and 10 HALO were significantly severer than that of 16 and 22 HALO. Cosine analysis showed survival time, body weight and white blood cell counts had significant circadian rhythms. Mice received L-OHP at 14.88 HALO had the longest survival time.

CONCLUSIONThe time factor should be considered in L-OHP chronchemotherapy of patients with OSCC in order to increase the efficacy, decrease the adverse reaction of the drug and to improve the life quality of patients with OSCC.