Inoculation of Lewis lung carcinoma cell enhances formalin-induced pain behavior and spinal Fos expression in mice
Jae-Gyun Choi1,†, Jae-Min Kim1,†,‡, Dong-Wook Kang1, Jung-Wan Choi1, 2, Jin Bong Park1, Seong-Hun Ahn3, Yeon Hee Ryu2, Hyun-Woo Kim1,*
1Department of Physiology and Medical Science, Brain Research Institute, College of Medicine, Chungnam National University, Daejeon, 35015, Korea
2KM Fundamental Research Division Korea Institute of Oriental Medicine, Daejeon, 34054, Korea
3Department of Meridian & Acupoint, College of Oriental Medicine, Wonkwang University, Iksan, 54538, Korea
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The first two authors equally contributed to this work.
Present address: Formulation Research Team, I.V. Solution Research Institute, JW Life Science, Dangjin 343-822, Korea
Received: February 22, 2016; Revised: June 1, 2016; Accepted: August 26, 2016; Published online: September 1, 2016.
The incidence of lung cancer has been rapidly increased and cancer patients at a later stage frequently suffer from the unbearable cancer-associated pain. However, pathophysiology of lung cancer pain has not been fully demonstrated due to lack of proper animal models. This study was designed to determine the effect of Lewis lung carcinoma (LLC) cell inoculation on formalin-induced pain behavior and spinal Fos expression in C57BL/6 mice. LLC cell (1.5X105, 2.5X105, 3.0X105 or 5.0X105) was inoculated into back or peri-sciatic nerve area. Back area was adopted to determine the circulating effect of inoculated cancer cell and peri-sciatic nerve area was used to evaluate the possible effect of contacting and circulating factor of cancer cell on formalin-induced pain. At post-inoculating day 7, LLC cell (5.0X105) inoculated both in back and peri-sciatic nerve area significantly increased formalin-induced paw licking time and spinal Fos expression as compared with that of cell media received control mice. Enhanced pain behavior and spinal Fos expression were significantly suppressed by the pretreatment of ibuprofen (250 mg/kg). Results of this study suggested that the circulating factor of LLC cell and inflammatory response may be critical to enhance pain sensation in the early stage of lung cancer cell inoculation.
Keywords: Fos, Lewis lung carcinoma, formalin, lung cancer, pain

© 2016 The Korean Society of Veterinary Science.