Skip to main content
. 2021 Nov 2;10:e70153. doi: 10.7554/eLife.70153

Figure 1. Cold-induced vascular response is impaired with ageing.

(a) Diagram illustrates the experimental setup of cold-induced vascular response protocol; FLPI from top measures the blood flow in the hindpaw of the anaesthetised mouse when on a heating mat in response to cold water immersion. The expanded component (highlighted by dotted red lines) shows the hindpaw region in which the blood flow is recorded, and a graph of typical blood flow response is shown. Recording is paused for cold treatment where one of the hindpaw is immersed in cold water for 5 min. (b) Representative FLPI image shows the blood flow in cold-treated hind paw at baseline, 2 min and 30 min after the cold water treatment. (c) Graph shows the raw blood flow trace (mean ± s.e.m.) of vascular response with cold (4 °C) water treatment (n = 8). (d) % change in hindpaw blood flow from baseline to 0–2 min following cold water treatment (maximum vasoconstriction). (e) The AUC to maximum vasoconstriction point assessed by area under the curve (AUC). (f) Time of blood flow recovery immediately after maximum vasoconstriction until the start of the plateau period. (g–h) RT-PCR CT analysis shows fold change of P21 and P16 gene expression normalised to three housekeeping genes in dorsal root ganglia (DRG) of young and aged mice. (i) Representative western blot of p21 in hindpaw skin of young and aged mice and densitometric analysis normalised to GAPDH. (BL = baseline). Data is presented as mean and all error bars indicate s.e.m. (n = 6–11) **p < 0.01, ***p < 0.001. (Two-tailed Student’s t-test).

Figure 1.

Figure 1—figure supplement 1. Analysis of cold-induced blood flow in the mouse paw.

Figure 1—figure supplement 1.

(a) The blood flow graph from cold treatment was used to calculate the maximum vasoconstriction, area under the curve (AUC) analysis of vasoconstriction and recovery of blood flow from cold treatment. It was not possible to measure blood flow whilst the paw was being cooled. The highlighted areas in blue shows the area of the graph from start of the 5 min baseline (BL) until peak vasoconstriction that was used to calculate the AUC analysis to detail the magnitude of the vasoconstrictor event. The time of immediate blood flow recovery (T) was calculated by measuring the time immediately after maximum vasoconstriction until it started to plateau back to baseline level (as shown by blue lines). (BL = Baseline). The maximum change of blood flow (%) was calculated using the equation below.