Initial thermal heat hypoalgesia and delayed hyperalgesia in a murine model of bone cancer pain

• Published in: Brain research 2003-04, Vol.969 (1), p.102-109
• Main Authors: Menéndez, Luis, Lastra, Ana, Fresno, Manuel F, Llames, Sara, Meana, Álvaro, Hidalgo, Agustı́n, Baamonde, Ana
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Bone Neoplasms - pathology; Bone Neoplasms - physiopathology; Cancer; Diseases of the osteoarticular system; Hot Temperature; Hyperalgesia - physiopathology; Hypoalgesia; Medical sciences; Mice; Models, Animal; Morphine; Morphine - pharmacology; Mouse; Naloxone; Naloxone - pharmacology; Narcotic Antagonists - pharmacology; Narcotics - pharmacology; Nociceptors - drug effects; Osteosarcoma; Osteosarcoma - pathology; Osteosarcoma - physiopathology; Pain; Pain - physiopathology; Physical Stimulation; Thermal hyperalgesia; Tibia - pathology; Tibia - transplantation; Time Factors; Tumor Cells, Cultured - transplantation; Tumors of striated muscle and skeleton
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/S0006-8993(03)02284-4

The recent development of rodent models of bone cancer pain has started to provide the basis for demonstrating the particular neurochemical and behavioral entity of cancer pain. Behaviourally, both spontaneous pain and hyperalgesia related to mechanical, but not thermal, noxious stimuli have been described in cancer-bearing animals. We have carried out a histological and behavioural study focused on the reactivity to noxious heat in C3H/HeJ mice receiving an intratibial injection of 10 5 NCTC 2472 cells. These cells, able to induce an osteosarcoma, break through bone into soft tissues 2 weeks after cell inoculation, producing a macroscopical increase of the limb size from the fourth week. Thermal reactivity is diminished during the first 2 weeks after cell implantation, this hypoalgesia being reversed by the administration of naloxone (10 mg/kg). In contrast, during the fourth and fifth weeks after NCTC 2472 cell implantation, an increased nociceptive heat reactivity, instead of hypoalgesia, was obtained. This thermal hyperalgesia was prevented by the systemic administration of morphine (15 mg/kg). Throughout the whole period studied, mice showed signs of spontaneous pain behaviour that reached its maximum 3 weeks after inoculation. In conclusion, we show that the presence of thermal heat hyperalgesia is preceded by an initial opioid-mediated hypoalgesic state, in this murine model of bone cancer pain.