Extended longevity of wild-derived mice is associated with peroxidation-resistant membranes

Abstract

Two lines of mice, Idaho (Id) and Majuro (Ma), both derived from wild-trapped progenitors, have previously been shown to have extended lifespans in captivity when compared to a genetically heterogenous laboratory line of mice (DC). We have examined whether membrane fatty composition varies with lifespan within the species Mus musculus in a similar manner to that previously demonstrated between mammal species. Muscle and liver phospholipids from these long-living mice lines have a reduced amount of the highly polyunsaturated omega-3 docosahexaenoic acid compared to the DC mice, and consequently their membranes are less likely to peroxidative damage. The relationship between maximum longevity and membrane peroxidation index is similar for these mice lines as previously observed for mammals in general. It is suggested that peroxidation-resistant membranes may be an important component of extended longevity.

Fig. 1

Fatty acid composition of phospholipids from skeletal muscle (A) and liver (B) from three strains of mice (Idaho, Majuro and DC) that differ in longevity. Values are shown for the following fatty acids (from bottom of each column): 16:0, 18:0, 18:1 n − 9, 18:1 n − 7, 18:2 n − 6, 20:4 n − 6, 22:5 n − 3, 22:6 n − 3. The columns do not add up to 100% because only data for the eight major fatty acids are shown. Individual fatty acids are identified by number of C atoms: number of double bonds followed by position of most terminal double bond. They are grouped in pairs as either saturated fatty acids (SFA), monounsaturates (MUFA), omega-6 polyunsaturates (n − 6 PUFA) and omega-3 polyunsaturates (n − 3 PUFA). Those fatty acids that significantly differ between mice strains have a different letter in the column (P < 0.05). (C) Shows the calculated Peroxidation index (mean PI ± S.E.M.) for the three mice strains. Lines indicate those values that are significantly different (P < 0.05) from one another.

Fig. 2

The relationship between the maximum lifespan (MLSP) and peroxidation index (PI) of phospholipids from skeletal muscle (A) and liver (B) for three mice lines (Id: Idaho, Ma: Majuro and DC: laboratory mice line) that differ in longevity. The skeletal muscle data are compared to that for mammal species in general and the liver data for mice are compared to the relationship for liver mitochondrial phospholipids for mammals in general (both taken from Hulbert, 2005).