Reduced Osteolytic Bone Resorption with Cold Plasma Treatment
Location
Philadelphia, PA
Start Date
11-5-2022 1:00 PM
End Date
11-5-2022 4:00 PM
Description
INTRODUCTION: Infection associated revision surgeries are painful, expensive, and can be limb or life threatening. Cold plasma is a promising non-antibiotic treatment that utilizes physical and chemical properties to disrupt biofilms. As our intention is to use plasma as treatment for infection, it is important to determine the isolated effect it has on bone and tissue. Therefore, the goal of this study is to determine the impact of the Apyx Medical J-Plasma on bone and surrounding musculature.
METHODS: At index surgery, Day -7, a central defect was created in a rat femur and screws were placed at the proximal and distal ends to secure a titanium lock plate. Revision surgery occurred one week later, at Day 0. The screws were removed, the surgical area was treated with Betadine (control) or J-Plasma, and four new holes were drilled to secure a new titanium plate. On Day 14, the femur was collected for microCT imaging and analysis, while the surrounding muscle tissue was collected for histology and qPCR. The ratio of bone volume to total volume for each hole was compared to that of a hole drilled after extraction, yielding values in terms of percentage of an original hole. These values compared the effects of plasma treatment on a defect created at Day -7 with no screw placed, and at Days -7 and 0 with screws placed at hole formation. Contralateral control samples were analyzed in their entirety to create a normalization that accounted for minor variations in hole location from sample to sample.
RESULTS: J-Plasma treatment reduced the amount of osteolytic cortical bone resorption to 6.7% compared to 8.0% of control, in the defect created at Day -7 with no screw. These results were not significant with a p-value of 0.67. In the Day -7 defect with the screw, there is a 7.9% increase in bone formation when plasma is applied compared to a 3.6% loss of cortical bone by resorption (p = 0.14). The same trend occurs when the defect is formed at Day 0 with a screw placed, causing 7.1% resorption to 0.9% (p = 0.11) formation. These measurements are clearly trending toward significance, and an increased sample size will be necessary.
Insight into the bone healing environment was assessed by qPCR of the surrounding muscle. Significantly increased levels of the anti-inflammatory cytokine SOCS3 was present when plasma treatment was applied as compared to control. Additionally, the levels of the pro-oxidant NOS2 are significantly reduced with plasma treatment.
Histology was used to determine the depth of fibrosis, elucidating the possible damaging effects plasma treatment could have on the surrounding tissues. This value was increased in plasma treatment, however the additional fibrosis was found to be statistically insignificant.
CONCLUSION: Prior literature has established cold plasma as a promising agent to target biofilms. This study shows cold plasma treatment is safe for bone and surrounding tissues, reduces bone resorption, and protects tissues from inflammation. These attributes, coupled with cold plasma’s microbicidal activity, could represent a new therapy for treating implant infection. We also plan to explore additional surgical uses of plasma due to its anabolic influence on bone.
Embargo Period
5-25-2022
Reduced Osteolytic Bone Resorption with Cold Plasma Treatment
Philadelphia, PA
INTRODUCTION: Infection associated revision surgeries are painful, expensive, and can be limb or life threatening. Cold plasma is a promising non-antibiotic treatment that utilizes physical and chemical properties to disrupt biofilms. As our intention is to use plasma as treatment for infection, it is important to determine the isolated effect it has on bone and tissue. Therefore, the goal of this study is to determine the impact of the Apyx Medical J-Plasma on bone and surrounding musculature.
METHODS: At index surgery, Day -7, a central defect was created in a rat femur and screws were placed at the proximal and distal ends to secure a titanium lock plate. Revision surgery occurred one week later, at Day 0. The screws were removed, the surgical area was treated with Betadine (control) or J-Plasma, and four new holes were drilled to secure a new titanium plate. On Day 14, the femur was collected for microCT imaging and analysis, while the surrounding muscle tissue was collected for histology and qPCR. The ratio of bone volume to total volume for each hole was compared to that of a hole drilled after extraction, yielding values in terms of percentage of an original hole. These values compared the effects of plasma treatment on a defect created at Day -7 with no screw placed, and at Days -7 and 0 with screws placed at hole formation. Contralateral control samples were analyzed in their entirety to create a normalization that accounted for minor variations in hole location from sample to sample.
RESULTS: J-Plasma treatment reduced the amount of osteolytic cortical bone resorption to 6.7% compared to 8.0% of control, in the defect created at Day -7 with no screw. These results were not significant with a p-value of 0.67. In the Day -7 defect with the screw, there is a 7.9% increase in bone formation when plasma is applied compared to a 3.6% loss of cortical bone by resorption (p = 0.14). The same trend occurs when the defect is formed at Day 0 with a screw placed, causing 7.1% resorption to 0.9% (p = 0.11) formation. These measurements are clearly trending toward significance, and an increased sample size will be necessary.
Insight into the bone healing environment was assessed by qPCR of the surrounding muscle. Significantly increased levels of the anti-inflammatory cytokine SOCS3 was present when plasma treatment was applied as compared to control. Additionally, the levels of the pro-oxidant NOS2 are significantly reduced with plasma treatment.
Histology was used to determine the depth of fibrosis, elucidating the possible damaging effects plasma treatment could have on the surrounding tissues. This value was increased in plasma treatment, however the additional fibrosis was found to be statistically insignificant.
CONCLUSION: Prior literature has established cold plasma as a promising agent to target biofilms. This study shows cold plasma treatment is safe for bone and surrounding tissues, reduces bone resorption, and protects tissues from inflammation. These attributes, coupled with cold plasma’s microbicidal activity, could represent a new therapy for treating implant infection. We also plan to explore additional surgical uses of plasma due to its anabolic influence on bone.