Cell experiment:

BAEC are incubated for 30 min with Naproxen (0.1 ng/mL to 1 mg/mL). Arachidonic acid (30 μM) is then added, and the cells are incubated for a further 15 min at 37℃. The medium is then removed, and radioimmunoassay is used to measure the formation of 6-keto-PGF,a, PGE2, thromboxane B2, or PGF2a[1].

Animal experiment:

Rats[3]To measure the analgesic effects of naproxen in a carrageenaninduced model of monoarthritis, Male Sprague–Dawley rats (n=48, 217±28 g) are randomly divided into four groups of 12 by an internally developed computer program, allowing the blind performance of the behavioral experiment. To induce hyperalgesia by inflammation, animals in groups 1B, 1C, and 1D receive a 40-μL intra-articular injection of a saline solution containing 7.5 mg/mL carrageenan in the left hind limb under isoflurane anesthesia (time=–1 h). Animals in group 1A receive no injection. After 1 h (time=0) the animals in groups 1A, 1B, 1C, and 1D receive oral doses of naproxen in saline of 0, 0, 7.5 and 30 μmol/kg, respectively. The doses and time points of measurements are selected on the basis of simulations predicting measuring a full concentration-effect relationship within the time-span of the experiment[3].Mice[2]Bleomycin (0.05 IU) is instilled intratracheally to C57BL/6 mice, which are then treated by micro-osmotic pump with vehicle, JNJ7777120 (40 mg/kg b.wt.), naproxen (21 mg/kg b.wt.), or a combination of both. Airway resistance to inflation, an index of lung stiffness, is assessed, and lung specimens are processed for inflammation, oxidative stress, and fibrosis markers[2].

Naproxen sodium is a nonselective cyclooxygenase inhibitor [1], with an ex vivo IC50 value of 35.48 μmol/L to cyclooxygenase-1 (COX-1) inhibition regarding naproxen plasma levels, and an ex vivo IC50 value of 64.62 μmol/L to cyclooxygenase-2 (COX-2) regarding naproxen plasma levels [2].

COX enzymes showed to be important for satellite cell fusion, proliferation and differentiation. COX-2 inhibition alone produced decreased satellite cell proliferation. Inhibition of both COX-1 and COX-2 decreased the fusion and differentiation of satellite cell [1].

Treatment with naproxen (0.5-1.5 mM) or licofelone (100-150 μM) was applied. After 48 h, the evaluation of HCA-7 cell viability was determined with trypan blue exclusion assay. Naproxen significantly decreased HCA-7 cell viability with an IC50 value of 1.45 ± 0.07 mM, and licofelone with an IC50 value of 72 ± 3.6 μM [3].

In four volunteers, 220 mg naproxen sodium b.i.d. was applied for 7 days. After a single dose and at steady state, maximal inhibition was as follows: 79% and 85% (COX-2), 94% and 93% (COX-1). In 2 of 4 volunteers applied with a single-dose administration, a greater than 95% COX-1 inhibition was transiently found at the time of maximal plasma concentration. In 1 of 4 volunteers throughout the 12-hour dose interval, a greater than 95% COX-1 inhibition was transiently found at steady state [2].

Treatments with placebo (PL) for 3 months or naproxen sodium (Nxs) 550 mg twice each day by mouth was applied to forty women suffering from Menstrual Migraine (MM). In the next 3 months, in an open study, active drug was applied to all the women. Compared to PL, treatment with Nxs significantly reduced the number of days of headache, the headache duration and intensity, and the analgesic consumption [4].

References:
[1].  Mendias CL, Tatsumi R and Allen RE. Role of cyclooxygenase-1 and -2 in satellite cell proliferation, differentiation, and fusion. Muscle Nerve, 2004, 30(4):497-500.
[2].  Hinz B, Cheremina O, Besz D, et al. Impact of naproxen sodium at over-the-counter doses on cyclooxygenase isoforms in human volunteers. Int J Clin Pharmacol Ther, 2008, 46(4):180-6.
[3].  Sances G, Martignoni E, Fioroni L, et al. Naproxen sodium in menstrual migraine prophylaxis: a double-blind placebo controlled study. Headache, 1990, 30(11):705-9.
[4].  Tavolari S, Bonafè M, Marini M, et al. Licofelone, a dual COX/5-LOX inhibitor, induces apoptosis in HCA-7 colon cancer cells through the mitochondrial pathway independently from its ability to affect the arachidonic acid cascade. Carcinogenesis, 2008, 29(2):371-80.