Electrophoretic Analysis of Brain Proteins from Young Adult and Aged Mice

Abstract

The purpose of this study was to electrophoretically examine proteins from mice of different ages to determine whether general changes occurred in protein levels during senescence and to relate the data to specific ageing hypotheses involving proteins. Proteins from whole brain, brain regions, soluble and ribosomal brain fractions, from young adult and senescent mice, were totally solubilized and subjected to polyacrylamide slab gel electrophoresis. The resulting gel patterns were then compared by examining the intensity of gel bands of the same migration distance. Positive controls were used to establish the high sensitivity of the electrophoretic method. For example, band intensity differences were observed when brain proteins from different species, different periods of growth and development, normal and mutant mice, and different brain regions were compared. Virtually all band intensities and, therefore, corresponding brain protein concentrations were unchanged when patterns from senescent mice were compared to patterns from younger adult mice. These results provide evidence against ageing hypotheses involving: (1) progressive programmed ageing; (2) protein cross-linking, and (3) a systematic shutdown of gene activity. The few, select, protein band changes that did occur provide evidence that (1) the volume of the brain vascular system decreases with age, and (2) the brain S-100 protein concentration increases with age.

Brain Poly(A)RNA During Aging: Stability of Yield and Sequence Complexity in Two Rat Strains

“…Our data also concur with the absence of age differences in the template activity of chromatin assayed in v i m from the mouse brain (Hill, 1976) and dog myocardium (Shirey and Sobel, 1972), or in the activity of chromatographically separated mouse brain RNA polymerases (Benson and Harker, 1978). Additionally, the absence of detectable age changes in polysomal poly(A)RNA agrees with the scarcity of age changes in one-dimensional gel electrophoretic profiles of proteins from various brain regions (Gordon and Finch, 1974;Vaughan and Calvin, 1976), in two-dimensional gel electrophoretic profiles of cervical ganglia proteins (Wilson et al, 1978), and in brain enzyme activities (Kellogg and Fridovich, 1976;Finch, 1977;Reis et al, 1977). These studies, however, could not detect changes in most of the > 50,000 different polypeptides predicted from brain mRNA complexity , the majority of which are probably present at very low concentrations.…”

Serum Lipoprotein Concentrations in Cystic Fibrosis

“…The LDL and HDL values from each patient were assigned a percentile rank, which was determined by comparing a patient's value to histo- Slightly higher VLDL values were observed in the CF patients than in the controls. This is in agreement with higher triglyceride levels in the CF group (108 + 52 as opposed to 57 + 34 mg/dl), for electrophoresis (9). Approximately 70 ,g of protein were loaded into each gel slot.…”

Review: Cerebral microvascular pathology in ageing and neurodegeneration

“…In mice, Sturrock [103] found no change in vessel density. Also, Vaughan and Calvin [104] showed a decrease in haemoglobin in the brains of older mice, which they concluded was due to decreased blood volume.…”