Photobiomodulation enhanced endogenous pain modulation in healthy volunteers.

To examine the effects of photobiomodulation (PBM) in healthy volunteers using photonic stimulation of acupuncture points on conditioned pain modulation (CPM), temporal summation of pain (TSP), and offset analgesia (OA), which reflect some aspects of endogenous pain modulation. We included 15 men and 15 women (age, 31.5 [27.3-37.0], body mass index, 25.7 [24.4-27.1], Fitzpatrick skin typing, II: 20, III: 8, IV: 2). CPM, TSP, and OA were evaluated after a sham procedure (control session) and after acupuncture point stimulation (LI4 and LI10 on the non-dominant forearm) using linear polarized near-infrared light irradiation (LPNILI; wavelengths peaked at approximately 1000 nm, output: 1.4 W/cm2, spot diameter: 10 mm, spot size: 1.02 cm2, maximum temperature: 40.5 °C, pulse width: 1 s, frequency: 0.2 Hz) (PBM session). Differences in CPM, TSP, and OA between the two sessions were evaluated by the paired t-test and Fisher's exact test (statistical significance: p < 0.05). Values indicate median [interquartile range]. LPNILI significantly increased CPM in all participants (control session: 12.1 [-4.5-37.4], PBM session: 23.9 [8.3-44.8], p < 0.05) and women (control session: 16.7 [-3.4-36.6], PBM session: 38.7 [24.6-52.1], p < 0.05). The CPM effect increment was significantly higher in women than in men (p = 0.0253). LPNILI decreased TSP in participants with higher TSP ratios (p = 0.0219) and increased OA in participants with lower OA scores (p = 0.0021). LPNILI enhanced endogenous pain modulation in healthy volunteers, particularly in women, as evaluated using CPM. CPM, TSP, and OA evaluations are potentially useful for discriminating PBM responders from non-responders.

Inhibition by Moxa smoke of NO production and iNOS expression in mouse macrophage-like cells Raw 264.7.

The biological activities of Moxa, used as moxibustion, have not been well documented. We investigated the effect of Moxa smoke on nitric oxide (NO) production by mouse macrophage-like Raw 264.7 cells. Moxa smoke failed to stimulate the Raw 264.7 cells to produce detectable amounts of NO, but rather inhibited the NO production by lipopolysaccharide (LPS)-activated Raw 264.7 cells. The 50% inhibitory concentration (IC50) of NO production by Moxa smoke (0.16%) was one order lower than the 50% cytotoxic concentration (CC50) (4.67%). Western blot and RT-PCR analyses demonstrated that a slightly higher concentration of Moxa is required to reduce the iNOS expression at protein and mRNA levels (IC50 = 0.99 and 2.03%, respectively). The inhibition of NO production by Moxa smoke is, thus, probably due to both the inhibition of iNOS expression and radical-scavenging activity. The present data suggest the possible anti-inflammatory effect of Moxa smoke.

Induction of cell death by pro-oxidant action of Moxa smoke.

Moxa smoke induced internucleosomal DNA fragmentation in human promyelocytic leukemic HL-60 cells, but not in other cell lines. The cytotoxic activity of Moxa smoke was significantly reduced by a popular antioxidant, N-acetyl-L-cysteine (NAC). Moxa smoke showed oxidation potential (measured by NO monitor) and produced carbon radical (measured by ESR spectroscopy). The addition of NAC significantly reduced both the oxidation potential and carbon radical intensity of Moxa smoke. Activity staining of polyacryamide gel electrophoresis of MnSOD revealed the possible modification of the conformation and/or activity of this enzyme at an early stage of HL-60 cell death. These data suggest that Moxa smoke induces cytotoxicity by its pro-oxidant action.

Partial purification of cytotoxic substances from moxa extract.

The major cytotoxic activity of Moxa was extracted with CH2Cl2 and partially purified by three cycles of silica gel column chromatography. The active fractions showed higher cytotoxicity against six human tumor cell lines (two oral squamous cell carcinoma, one salivary gland tumor, one melanoma, two leukemia) than three normal oral human cells (gingival fibroblast, periodontal ligament fibroblast, pulp cell). All fractions failed to protect the cells from the cytopathic effect induced by HIV infection. ESR spectroscopy showed that all fractions produced little or no radical under alkaline conditions, while showing much lower O2- scavenging activity, generated by hypoxanthine-xanthine oxidase reaction, than antioxidants and polyphenols. Active fractions induced DNA fragmentation in HL-60 cells, but failed to modify the mobility and activity of mitochondrial Mn-containing superoxide dismutase (MnSOD), in contrast to Moxa smoke. These data suggest that the active principles in the Moxa extract might be different from that in Moxa smoke, which produced carbon radical and modified MnSOD mobility and activity.