Fig. 5.

Partial nullification of caffeic acid's beneficial effects on DN through IGF-1 signaling inhibition via PPP. (A) Longitudinal changes in mechanical withdrawal thresholds from Baseline (BL) up to 8 weeks post-STZ injection. An asterisk (*) represents P < 0.05 when comparing the DN group with the control group at specific time points. Blue hashtags (#) denote P < 0.05 when comparing the CA group with the DN group at the indicated time points. Purple symbols (&) signify P < 0.05 when comparing the CA + PPP group with the CA group at these time points. Statistical significance was evaluated via a multiple comparison test following a two-way ANOVA. (B) Sequential alterations in thermal withdrawal latency from BL to 8 weeks post-STZ injection. The notations are as explained in (A). (C) Assessment of serum IGF-1 concentration, 8 weeks post-STZ administration. (D–F) Comparative analysis of spinal protein levels of IGF-1, phosphorylated IGF1R (p-IGF1R), and total IGF1R, 8 weeks after STZ injection. Statistical significance is indicated as *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001, with 'ns' denoting non-significant results.