Using Flow Cytometry To Identify Key Cell Populations Implicated In Opioid-Induced Osteopenia In A Cancer Induced Bone Pain Model

Abstract

Strong opioid analgesics such as morphine are the first line of analgesic treatment for alleviating a variety of acute and chronic ailments. However, prolonged opioid administration causes detrimental side effects. This study investigates one such side effect: chronic peripheral inflammation. To determine whether morphine can exert an inflammatory effect on peripheral tissues such as bone, we created a cancer induced bone pain (CIBP) model. We then constructed an immunophenotyping panel that could identify standard inflammatory and bone degradative populations to see whether morphine can induce the infiltration and proliferation of these cell populations. We also wanted to know if using flow cytometry on treated full femur samples is viable in tracking such populations. Results showed that full femur processing does not impact cell viability and is thus a practical alternative to collect cells for analysis. In addition, we observed some preliminary trends indicating morphine can induce the infiltration of immune and bone degradative cells to the bone marrow. These findings are consistent with previous studies examining orthopedic outcomes of morphine treated patients. This study serves as the foundation for our TLR-4 mediated inflammation hypothesis and will be supplemented with knock-out and biochemical studies in the future.