PMC

Panel A: Approximately 100 pmol of the dimethyl acetal of 2-chloropalmitaldehyde and 200 pmol of the methyl ester of arachidic acid in 1 µl of petroleum ether was injected with a 50 to 1 split onto the GC column and detection was by flame ionization. Peaks 1–3 are the solvent peak, the dimethyl acetal of 2-chloropalmitaldehyde and the methyl ester of arachidic acid, respectively. Panel B: Approximately 2 pmol of the dimethyl acetal of 2-chloropalmitaldehyde in 1 µl of petroleum ether was injected in pulsed splitless mode onto the GC column and detected by positive ion-chemical ionization mass spectrometry. Under these conditions, the dimethyl acetal eluted at 7.0 min. The mass spectrum of this peak is shown in the inset. Panel C: Approximately 2 pmol of the dimethyl acetal of 2-chloropalmitaldehyde in 1 µl of petroleum ether was injected in pulsed splitless mode onto the GC column and detected by electron impact ionization mass spectrometry. Under these conditions, the dimethyl acetal eluted at 6.7 min. The mass spectrum of this peak is shown in the inset.

Panel A: Approximately 30 pmol of the dimethyl acetal of 2-bromopalmitaldehyde and 50 pmol of the fatty acid methyl ester of palmitic acid in 1 µl of petroleum ether was injected with a 50 to 1 split onto the GC column and detection was by flame ionization. Peaks 1–3 are the solvent peak, the fatty acid methyl ester of palmitic acid and the dimethyl acetal of 2-bromopalmitaldehyde, respectively. Panel B: Approximately 2 pmol of the dimethyl acetal of 2-bromopalmitaldehyde in 1 µl of petroleum ether was injected in pulsed splitless mode onto the GC column and detected by positive ion-chemical ionization mass spectrometry. Under these conditions, the dimethyl acetal eluted at 7.4 min. The mass spectrum of this peak is shown in the inset. Panel C: Approximately 2 pmol of the dimethyl acetal of 2-bromopalmitaldehyde in 1 µl of petroleum ether was injected in pulsed splitless mode onto the GC column and detected by electron impact ionization mass spectrometry. Under these conditions, the dimethyl acetal eluted at 7.0 min. The mass spectrum of this peak is shown in the inset.

Quantification of CAC intermediates in the heart following infusion of dimethyl succinate and in the brain following infusion of dimethyl malonate, and extended summary cytoprotection and neurological scores of rats subjected to tMCAO IR in vivo ± dimethyl malonate infusion. a, Effect of intravenous infusion of dimethyl succinate on CAC metabolite abundance in the ischaemic and non-ischaemic myocardium(normoxia and peripheral heart tissue + dimethyl succinate n = 3; ischaemia + dimethyl succinate n = 4; α-KG and aconitate in peripheral heart tissue n = 2). b, Profile of mitochondrial CAC metabolite levels following tMCAO ischaemia ± dimethyl malonate (n = 4). c, Representative images of cross-sections from rat brains after undergoing tMCAO in vivo ± treatment with dimethyl malonate. Brains were treated with hematoxylin and eosin to delineate infarcted tissue. d, Locomotor and sensorimotor assessment of rats by quantification of average number of footfalls following tCMAO ± dimethyl malonate (control n = 6; dimethyl malonate n = 4). *, p < 0.05; **, p < 0.01. Data are shown as the mean ± s.e.m of at least three biological replicates, unless otherwise stated.

Schematic diagram of the experimental design. (A) Changes in pain-related behaviors after MIA injection in rats. (B) To clarify if consecutive administration of dimethyl fumarate, an Nrf2 activator, can attenuate established OA pain, dimethyl fumarate (30, 100, 300 mg/kg) was orally administered once a day from day 14 for 5 days in a row. All behavioral tests were experienced 2 hours after dimethyl fumarate administration every day. (C) To clarify whether dimethyl fumarate, can abolish the development of OA pain in the early stage of OA, starting from day 0, rats were orally administrated dimethyl fumarate (300 mg/kg) once a day for 7 days in a row. All behavioral tests were experienced on day 0 before the rat model was built, and on day 3, day 7, day 14, and day 21. (D) To clarify if an Nrf2 inhibitor, trigonelline, can abolish the effect that dimethyl fumarate attenuate OA pain, 20 mg/kg trigonelline was intraperitoneal injection 30min before dimethyl fumarate. All behavioral tests were experienced 30 min before inhibitor administration and 2 h after dimethyl fumarate administration.