The effects of combining pulsed electromagnetic field stimulation with A 2A adenosine receptor agonist CGS-21680 on apoptosis and inflammation of nucleus pulposus cells in rats with intervertebral disc degeneration / 中华物理医学与康复杂志

ABSTRACT

Objective:To explore the effect of combining pulsed electromagnetic field (PEMF) stimulation with A 2A adenosine receptor agonist CGS-21680 on apoptosis and inflammation of nucleus pulposus cells in cases of intervertebral disc degeneration. Methods:Forty-eight Sprague-Dawley rats were randomly divided into a sham operation group (Sham group), an intervertebral disc degenerative disease group (Model group), an A 2A adenosine receptor agonist CGS-21680 group (Agonist group), and a group in which PEMF was combined with CGS-21680 (Observation group). The rat model of intervertebral disc degeneration (IDD) was established in all other groups than the sham operation group. The rats in the Agonist group were injected with 100μL of CGS-21680 (100μg/kg) at the L 5-6 intervertebral disc. The Observation group was injected with CGS-21680 similarly but then received 14 conse-cutive days of PEMF stimulation (30min/time). The Sham and Model groups were injected with the same amount of normal saline solution. Eight weeks later, HE staining was used to evaluate the pathological changes in the intervertebral disc tissues. The expression of type II collagen was determined by immunohistochemistry. The content and mRNA expression of inflammatory factors interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were determined using enzyme-linked immunosorbent assays and reverse transcription-polymerase chain reactions (RT-PCRs). The protein and mRNA levels of A 2A, NLRP3 and caspase-3 were determined by western blotting and RT-PCR. Results:The degeneration in the nucleus pulposus and annulus fibrosus in the Model group was significant, while significantly less shrinkage, necrosis and fibrous annulus rupture was observed in the Observation group. Compared with Model and Agonist groups, the positive expression of Col Ⅱ in the nucleus pulposus, A 2AR protein levels and relative expression of its mRNA had all increased significantly in the Observation group, while the average levels and mRNA expression of pro-inflammatory cytokines IL-6 and TNF-α had decreased significantly. The average protein level and mRNA expression of NLRP3 and caspase-3 in the intervertebral disc tissues of the Observation group were significantly lower than in the Model and Agonist groups. Conclusions:Combining pulsed electromagnetic field stimulation with A 2A adenosine receptor agonist CGS-21680 can inhibit the apoptosis of nucleus pulposus cells, alleviate disease response and delay IDD by up-regulating the activity of A 2A receptors and down-regulating the expressions of pro-inflammatory factors IL-6, TNF-α, NLRP3 and caspase-3 in nucleus pulposus cells.