Article Figures & Data
Figures
- Figure 1.
Neuroprotective effect of the fat-1 gene in vitro. DRGs were dissected from WT mice, WT mice fed a diet rich in ω-6, and mice containing the fat-1 gene fed a high ω-6 diet, and the dissociated cells were cultured for 48 h. A, Representative images of DRG cultures showing the method of assessing cell death after injury. EthD-1 binds to DNA in the nucleus of dead cells and fluoresces red (white arrow indicates dead neuron), whereas live cells have no EthD-1 nuclear stain (arrowhead). Scale bar, 100 μm. Cultures were exposed to either mechanical stretch injury (B) or hypoxic injury (C), and neuronal cell death assessed with EthD-1. Neuronal injury increased compared with non-injured controls only in the WT and WT ω-6 groups (*p < 0.05, **p < 0.005). Cell death was significantly reduced in the fat-1 group compared with both WT and WT ω-6 injured groups (#p < 0.05, ##p < 0.005). Error bars indicate SEM for n = 3.
- Figure 2.
Neurotrophic effects of ω-3 PUFA. A, DRGs were dissected from WT mice or mice containing the fat-1 gene fed on a high ω-6 diet, and the dissociated cells were cultured for 18 h before being stained with PGP 9.5 to view neurites. Length of the longest neurite (B) and number of branches (C) were then assessed. Neurons from fat-1 mice showed significantly longer neurites and increase in branching than neurons from WT ω-mice (*p < 0.05). Error bars indicate SEM for n = 3.
- Figure 3.
Functional recovery after sciatic nerve crush assessed with VF filaments. The baseline withdrawal threshold of each of the hindpaws using VF filaments as determined for each mouse before surgical manipulation (day 0) and on days 1, 4, and 7 d after injury. There was no difference in pre-injury withdrawal thresholds between WT ω-6 and fat-1 groups, but at 4 d after injury, there was a statistical difference between the response of the two groups, and this continued to day 7 (*p < 0.05). Error bars indicate SEM for n = 5 animals per group.
- Figure 4.
Motor function recovery after sciatic nerve crush assessed with the SFI. Functional motor recovery in mice was quantified by measuring the SFI. Print length (PL), toe spread (TS), and intermediary toe spread (ITS) were measured, and the SFI was calculated before injury and day 7 after injury. There was no significant difference between pre-injury values in the two groups. On day 7 after injury, there was a significant loss in activity (*p < 0.05), although this loss was significantly less in the fat-1 group compared with WT ω-6 mice (#p < 0.05). Error bars indicate SEM for n = 6 animals per group.
- Figure 5.
ATF-3 and GAP-43 expression in DRG neurons 7 d after sciatic nerve injury. Immunoreactivity for ATF-3 (A) and GAP-43 (B) was analyzed in L4 and L5 DRG neurons removed 7 d after sciatic nerve crush. C, Example of neurons positive for ATF-3 and GAP-43 are marked with a yellow arrow. Scale bar, 100 μm. ATF-3 and GAP-43 staining detected in lumbar DRG neurons contralateral (Contra) to nerve injury was low. Both ATF-3 and GAP-43 staining was seen in a high proportion of cells in the ipsilateral (Ipsi) DRG after injury (*p < 0.05). There was a significant difference between WT ω-6 and fat-1 in the percentage of neurons expressing ATF-3 after injury, with a smaller percentage of ATF-3 neurons in fat-1 mice (#p < 0.05) (means ± SEM, n = 11 animals per group).
- Figure 6.
GAP-43 and NF200 staining after sciatic nerve injury. Immunoreactivity for GAP-43 (A) and NF200 (B) was analyzed in transverse sections of sciatic nerve, 6 mm from the crush site 7 d after injury. Scale bar, 100 μm. C, GAP-43 staining was significantly increased after injury. There was no statistical difference between fat-1 and WT ω-6 groups. NF200 staining decreased in both groups after injury, but there was significantly less staining in the WT ω-6 group (*p < 0.05, means ± SEM, n = 11 animals per group). Contra, Contralateral; Ipsi, ipsilateral.
- Figure 7.
Response of the muscle after sciatic nerve injury. Muscle weight (A) and muscle fiber area (B) were analyzed 7 d after sciatic nerve crush. There was an increased muscle weight in the fat-1 group compared with WT (*p < 0.05). The muscle fiber area was also significantly higher compared with WT ω-6 animals (means ± SEM, n = 11 animals per group). C, H&E staining of contralateral (Contra) and ipsilateral (Ipsi) muscle from WT and fat-1 mice.
Tables
- Table 1.
Fatty acid composition of phospholipids extracted from DRG (n = 3) and spinal cord (n = 4) from WT mice and mice expressing the fat-1 gene fed a diet enriched in ω-6 PUFA
Fatty acid WT ω-6 diet fat-1 ω-6 diet DRG 14:0 0.75 ± 0.04 0.73 ± 0.05 16:0 30.65 ± 0.73 30.91 ± 0.71 18:0 34.38 ± 0.31 34.55 ± 0.72 20:0 2.58 ± 0.29 2.44 ± 0.24 Σ Saturated 68.37 ± 1.38 68.64 ± 1.71 18:1 11.78 ± 0.47 11.53 ± 0.31 20:1 0.37 ± 0.03 0.37 ± 0.03 Σ Monounsaturated 12.15 ± 0.51 11.90 ± 0.34 18:2n-6 (LA) 3.71 ± 0.15 3.60 ± 0.20 20:4n-6 (AA) 5.53 ± 0.07 5.09 ± 0.14* 22:4/5n-6 (DTA/DPA) 4.33 ± 0.31 2.44 ± 0.02* Σ (n-6) PUFA 13.56 ± 0.52 11.13 ± 0.35 20:5n-3 (EPA) 0.89 ± 0.06 0.98 ± 0.02 22:5n-3 (DPA) 0.91 ± 0.07 1.68 ± 0.16* 22:6n-3 (DHA) 4.11 ± 0.32 5.67 ± 0.14* Σ (n-3) PUFA 6.18 ± 0.54 8.32 ± 0.32 Spinal cord 14:0 0.51 ± 0.05 0.43 ± 0.03 16:0 28.84 ± 0.61 28.43 ± 0.76 18:0 34.01 ± 0.42 33.17 ± 1.00 20:0 3.60 ± 0.18 3.82 ± 0.11 Σ Saturated 66.97 ± 0.32 65.85 ± 0.47 18:1 7.67 ± 0.21 7.91 ± 0.52 20:1 1.73 ± 0.08 1.84 ± 0.05 Σ Monounsaturated 9.40 ± 0.14 9.75 ± 0.29 18:2n-6 (LA) 2.12 ± 0.05 2.13 ± 0.10 20:4n-6 (AA) 5.51 ± 0.22 5.01 ± 0.15 22:4n-6 (DPA) 4.33 ± 0.25 3.55 ± 0.37 Σ (n-6) PUFA 11.96 ± 0.17 10.69 ± 0.21 20:5n-3 (EPA) 1.11 ± 0.05 1.09 ± 0.12 22:5n-3 (DPA) 1.97 ± 0.05 3.34 ± 0.28* 22:6n-3 (DHA) 10.56 ± 0.57 13.36 ± 0.28* Σ (n-3) PUFA 13.64 ± 0.25 17.80 ± 0.16 ↵Data expressed as mol% of total fatty acids ± SD (*p < 0.05). EPA, Eicosapentaenoic acid; DTA, docosatetraenoic acid; AA, arachidonic acid; LA, linoleic acid.
