Fig. 5

Increased extraneural fibrosis around median nerve of task rats. a-e Representative images of median nerve branches (N) at the level of the wrist in a FRC rat (a), 10-wk HRHF rat (b), from two different 10-wk HRHF+TM rats (c and d), and TR-then-TM rat (e). Double-headed arrows in Panel B points out the spread of the extraneural connective tissue into surrounding loose areolar connective tissue in a 10-wk HRHF rat. Panels c and d show that the expanded epineurium appears connected to muscles (M) and tendons (T) in the 10-wk HRHF+TM rats. Panel E shows that a nerve from a TR-then-TM rat looks histologically similar to a FRC rat. Ct = connective tissue; M = lumbrical muscle; N = nerve; T = tendon. Scale bar = 25 μm. f Quantification of extraneural fibrosis at the level of the wrist, within a 50 μm distance from the edge of the nerve/epineurium juncture. **: p < 0.01, compared to groups as shown. Mean + 95% CI is shown for: FRC rats (n = 10), TR-then-TM (n = 10 reach limbs), and 10-wk HRHF rats (n = 13 reach limbs) and 10-wk HRHF+TM rats (n = 8 reach limbs)