1. Presenter:
Hayden Isaacs
(Class of 2019)
PI:
Dr. S. Mohan
Assistant Professor
DPSR
Bench to Bedside:
Role of IL-1beta in Morphine Tolerance
Using a Mouse Model for Postoperative
Pain

2. INTRODUCTION & RELEVANCE -
Postoperative Pain
Pain
● Most feared problem among patients
● Inadequately treated in 50% of all surgical procedures
● More than 80% of patients experience postoperative pain
● 71% experience moderate to severe pain
● 75% believe it is “necessary to feel pain following surgery”
● 8% postpone surgery because of concerns associated regarding pain
Apfebaum JL et alk., Anesth Analg 2003:97, 534-540
Gottschal A, Smith DS, Am Fam Physician 2001,63: 1979-1984

3. INTRODUCTION & RELEVANCE -
Morphine and Tolerance
● Morphine - an opioid pain medication that is used to treat moderate to severe pain.
●Can lead to a multimodal (use of more than one drug) practice which is being used
more frequently for pain relief.
●Tolerance can be quick to develop.
● Tolerance - is a person's diminished response to a drug, which occurs when the drug is
used repeatedly and the body adapts to the continued presence of the drug.

4. INTRODUCTION & RELEVANCE -
Mechanism behind opioid tolerance
● Mu-opioid receptor is G-protein coupled receptor (GPCR) and when activated
●leads to decreased excitation of pain pathway
● Agonist stimulation inhibits cAMP formation which leads to suppression of Na+ and Ca+
channels resulting in analgesia
● Over time G-Proteins in the G-protein mediated mechanism can lead to decreased
excitability through opioid receptor desensitization

5. ● IL-1 beta is a pro-inflammatory cytokine that is
produced by activated macrophages and glial
cells during inflammatory conditions
● IL-1 beta affects opiate-dependent pathways by
upregulating the expression of the mu-opioid
receptor
● IL-1 beta activates IL-1R and can result in the
NF-kappa beta mediated increase in cytokines,
chemokines and adhesion factors involved in
tissue injury and inflammation
INTRODUCTION & RELEVANCE –
Interleukin-1beta (IL-1beta)

6. To determine whether blockade of the IL-R1 limits morphine tolerance and
dependence in a post-operative pain model using WT and IL-R1-/- mice
RESEARCH AIM
RESEARCH HYPOTHESIS
Our hypothesis is that deletion of the IL-R1 receptor will alleviate pain and
decrease the incidence of opioid-induced hyperalgesia

7. STUDY DESIGN AND METHODS
Three-day study
● B57/BL6 (B6) mice:
● Wild-type (n=10; 5 each for morphine and saline)
● IL-1R KO (n=10; 5 each for morphine and saline)
● Pain (acute) model:
● 5 mm plantar incision on the right hindpaw
● P0: day of surgery
● P1-3: postoperative days
● Morphine (10mg/kg, s.c.) injected once-daily
MECHANICAL SENSITIVITY
Brennan et al., 2009

8. METHODS (Cont.)
● Three devices used to conduct behavioral studies:
● Dynamic Plantar Anesthesiometer (Von Frey)
● Mechanical
● Plantar Test (Hargreaves method) Analgesia Meter
● Heat
● Rotarod
● Motor Coordination
MECHANICAL SENSITIVITY
HEAT SENSITIVITY
MOTOR COORDINATION
Site of testing

9. Results – mechanical sensitivity
Three-day study
Post incision injury (day)
Time(sec)
Time(sec)
N = 5 N = 5 Post incision injury (day)
Ipsilateral (right) hindpaw

10. Results – heat sensitivity
Three-day study
Time(sec)
Time(sec)
N = 5 N = 5Post incision injury (day) Post incision injury (day)
Ipsilateral (right) hindpaw

11. Results – motor coordination
Three-day study
Time(sec)
Time(sec)
N = 5 N = 5Post incision injury (day) Post incision injury (day)

12. Conclusion and Future Studies
In the morphine treated groups:
●differences were found in mechanical, heat and motor coordination between
WT and IL-1R KO mice at post-op., day 2 and 3
Future studies:
●Conducted a longer six-day study (morphine injected (10mg/kg S.c.) daily
●Measure changes in genes – IL-1b and NMDAR in skin, spinal cord and brain
tissues

13. Acknowledgements
Thank you:
●Dr. Mohan Ph.D. (PI)
●Hannah Claar (Class of 2019)
●Sarah Stevens (MU-BMS Ph.D. graduate student)

14. References
Byrne, Linda Staikos et al. “Interleukin-1 Beta-Induced up-Regulation of Opioid Receptors in the
Untreated and Morphine-Desensitized U87 MG Human Astrocytoma Cells.” J of Neuroinflammation 9
(2012): 252
Viviani, B., et al. "Interleukin-1β Enhances Nmda Receptor-Mediated Intracellular Calcium Increase
through Activation of the Src Family of Kinases." J of Neuroscience 23.25 (2003): 8692-700
Mohan, Shekher et al. “Dual Regulation of mu Opioid Receptors in SK-N-SH Neuroblastoma Cells by
Morphine and Interleukin-1β: Evidence for Opioid-Immune Crosstalk.” J of neuroimmunology 227.1-2
(2010): 26–34