Physical exercise attenuates inflammation via suppression of systemic macrophage activation

s / Osteoarthritis and Cartilage 22 (2014) S57–S489 S309 538 PHYSICAL EXERCISE ATTENUATES INFLAMMATION VIA SUPPRESSION OF SYSTEMIC MACROPHAGE ACTIVATION S. Agarwal, A. Blazek, N. Young, L-C. Wu, B. Lebelebicioglu, T. Hewett, W. Jarjour, N. Weisleder. The Ohio State Univ., Columbus, OH, USA Purpose: Earlier reports have shown that physiologic levels of exercise (EX) suppress joint inflammation in OA in humans and in the experimental models of OA. However, the mechanisms that explain such effects of EX are little understood. Here we show that EX suppresses local and systemic activation of macrophages to attenuate inflammation. Methods: All protocols were preapproved by the IACUC at The Ohio State University. Transgenic BALBc female mice (12-14 wks old) containing firefly luciferase cDNA in NF-kB response elements (NFkB-REluc mice; Caliper Life Sciences, MA) were used as a tool to study transcriptional regulation of the NF-kB gene, for examining the effects of exercise (treadmill walking at 8M/min) on the cells involved in inflammation. The inflammationwas triggered by injection of LPS (1 mg/ gm body weight) or IL-1b (50 ng/30 g body weight) in the right ankle of the mice. Mice received following treatments, (i) no treatment (ii) EX alone, (iii) LPS or IL-1beta injection alone, (iv) LPS or IL-1beta injections and EX. The activation of NF-kB in the right ankle and systemic lymph nodes was assessed 2 hrs, 24 hrs, 48 hrs or 5 days post induction of inflammation by examining the luciferase activity by digital imaging (IVIS 100) or by immunohistochemistry in vivo and in vitro. The induction of proinflammatory cytokines in the serum and tissue samples was assessed by Multiplex ELISA assays (Biorad Labs). Statistical analysis was performed by one-way ANOVAwith Tukey’s post hoc or Ttest. Results: Control NFkB-RE-luc mice and those exposed to exercise alone did not exhibit significant NF-kB activation of F4/80þ macrophages. LPS injection in right ankle provoked a systemic and local inflammatory response that was 6-8 fold greater within 2 hours of LPS administration. Mice exposed to exercise following LPS injection showed a significant inhibition of LPS-induced NF-kB activation in the macrophages. However, mice exposed to exercise following LPS injection showed more than 90% suppression of NF-kB activation at the site of LPS injection and in all lymph nodes. Further analysis of NF-kB activation revealed that LPS activated NF-kB primarily in the F4/80þ macrophages in axillary and inguinal lymph nodes, spleen and mesentery, which was effectively suppressed by EX in all of these lymph nodes and the site of injection. Immunofluorescence analysis for the presence of NF-kB in all of these tissue confirmed that exercise inhibited NF-kB nuclear translocation and its synthesis in the F4/80þ macrophages. To gain molecular insight into the signaling affected by inactivation of NF-kB, we assessed the toll like receptor-4 (TLR-4) levels on the macrophages and serum levels of cytokines that follow NF-kB activation. Assessment of major pro-inflammatory cytokines IL-1b, TNF-a, IL-6, IL17, IL-12 and IL-8 all showed up-regulation by LPS, whereas EX effectively suppressed pro-inflammatory cytokine induction. Similarly, he expression of TLR-4 was suppressed by EX in LPS activated F4/80þ macrophages. The above findings prompted us to examine whether the anti-inflammatory effects of exercise are sustained. In these experiments mice were either exercised every day or only for one day post LPS administration. The mice exposed to exercise every day suppressed NF-kB activation in a sustained manner. However, effects of exercise were transient in suppressing NF-kB activation and lasted only 24 h following exercise. Conclusions: The findings suggest that exercise is a systemic inhibitor of inflammation and its actions are mediated via suppression of NF-kB activity in the F4/80þ macrophages, the cells responsible for initiation and perpetuation of inflammation. Furthermore, EX is a potent biological response modifying signal and potentially an indispensable tool to regulate inflammation in OA and other joint diseases. 539 MEDIAL ABRASION SYNDROME AS A CAUSE OF KNEE OSTEOARTHRITIS S-R. Lyu yz, D-S. Liu x, H-S. Wang k. y Tzu-Chi Dalin Gen. Hosp., Chiayi, Taiwan; z Tzu-Chi Univ., Hualien, Taiwan; xAdvanced Inst. of Manufacturing for High-tech Innovations and Dept. of Mechanical Engineering, Natl. Chung Cheng Univ., Chiayi, Taiwan; kDept. of Anatomy and Cell Biology, Natl. Yang-Ming Univ., Taipei, Taiwan Purpose: Knee osteoarthritis (OA) is a prevailing health problem and its etiology is still not defined. Medial plica related medial abrasion syndrome (MAS) has long been declared to be a cause of knee disability. We therefore conducted a series of prospective studies to verify the role of MAS as a cause of knee OA. The outcomes of arthroscopic treatment for this syndrome were also evaluated. Methods: In a one-year duration, 571 knees of 367 patients having OA and received arthroscopic treatment for MAS were enrolled into these studies. Construction of three-dimensional dynamic finite element model: An experimental study on the tensile strength of the medial plica from 50 knees was conducted using high precision micro-force tensile tests. The force-deflection curves resulting from these tests were transferred to stress-strain curves to obtain the Young’s moduli of these specimens. In another selected 30 knees with different size of medial plica, the inner margins of the plicae were located by inserting needles percutaneously under direct vision during arthroscopic examination. The topographic changes of the margins of these plicae during knee motion were recorded by fluoroscopy and analyzed. Based on the findings of these pilot studies, a three-dimensional dynamic finite element model was constructed and used to investigate themagnitudes of the cyclic pressures acting on the cartilage of the medial femoral condyles by different types of medial plicae with various Young’s moduli. Biochemical analysis: Interleukin-1b (IL-1b), matrix metalloprotease-3 (MMP-3) and MMP-3 mRNA expressions in the plica and pannus-like tissue isolated from 24 knees were investigated by immunohistochemistry, western blotting, reverse transcriptase polymerase chain reaction (PCR) and real-time PCR to clarify the impact of medial plica on cartilage destruction. Surgical treatment of MAS: Arthroscopic medial release (AMR) targeted on elimination of MAS and regaining soft tissue balance around patello-femoral joint was developed to treat these knees. The Knee Society score (KSS) and the knee injury and osteoarthritis outcome score (KOOS) were used for subjective outcome study. The roentgenographic changes of femoral-tibial angle (FTA) and joint space width (JSW) were evaluated for objective outcomes. Results: Three-dimensional dynamic finite elementmodel: The Young’s modulus of the plica was found to be ranging from 10 to 110 MPa and has positive correlation with patient’s age. All types of plicae remained in contact with the medial femoral condyles and shifted medially when the knees moved from extension to flexion. The contact pressures were positively correlated with the Young’s moduli of the medial plicae. The maximum contact pressures of all simulation scenarios occurred when the knees moved beyond 50 of flexion. When the Young’s moduli of medial plicae were set greater than 60 MPa, all types of plicae would elicit contact pressures greater than 10 MPa on the medial femoral condyles. Biochemical analysis: Immunohistochemistry showed that MMP-3 was highly expressed in the plica and pannus-like tissue on the femoral condyle. Western blotting of cultured supernatants showed that interleukin-1b (IL-1b) treatment induced MMP-3 release by cells isolated from pannus-like tissue or the plica. Reverse transcriptase PCR and real-time PCR analysis showed that MMP-3 mRNA levels were increased after IL-1b treatment of the cultured cells. MMP-3 and IL-1b mRNAs were also found highly expressed in the plica and pannus-like tissue. Surgical outcomes: There were 505 knees in 326 patients available with more than 3 years follow-up and the mean follow-up period was 38months (SD 3). Themean age of these patients at the time of surgery was 60 (SD 10). All of the knees were found to have the structure of pathologic medial plica. One hundred and thirty-four knees