Figure 8

Randomized control trial evaluating the result of lymphatic heart excision on the rate and morphology of limb regeneration. (a) The randomized control trial design: n = 62 newts were enrolled and separated into 4 blocks, each block was randomized into a study and control group by a blinded independent assistant. Follow-up was complete in 52 newts, 10 newts died immediately postoperative. (b) There was no statistically significant difference in the overall rate of regeneration between study and control groups (Kolmogorov–Smirnov Z = 0.662, p = 0.773). (c–h) Subgroup analysis also showed no statistically significant difference in regeneration rates between study and control newts after unilateral LH excision (Kolmogorov–Smirnov Z = 0.730, p = 0 .660), regardless of the timing of amputation immediate amputation after LH excision (Kolmogorov–Smirnov Z = 0.617, p = 0.841) and amputation delayed 1-week post LH excision (Kolmogorov–Smirnov Z = 0.661, p = 0.774). Similarly, no significant difference between study and control newts was found after incremental bilateral LH excision (Kolmogorov–Smirnov Z = 0.778, p = 0.579) regardless of the timing of amputation immediate amputation (Kolmogorov–Smirnov Z = 1.284, p = 0.074) and amputation delayed 1-week PO (Kolmogorov–Smirnov Z = 1.193, p = 0.116). (i) Comparison of LH excision study newts from the different experimental batches (excluding controls) also showed no significant difference in the time taken to complete regeneration (Kruskal–Wallis H(3) = 0.1.229, p = 0.746). (j) Comparison of the morphological abnormalities in the regenerated limbs showed no statistically significant difference (p = 0.150) between study and control newts. Data represent mean ± standard deviation (error bars).