At 15 days of renal ablation, basal CKD animals already showed a significant increase in the renal cortical interstitial area occupied by collagen, as well as in the fraction of the cortical interstitium occupied by α-SMA, when compared to the control group (2.0 ± 0.3 and 3.6 ± 0.7 vs. 1.1 ± 0.2 and 1.0 ± 0.1, p < 0.05), characterizing the presence of interstitial fibrosis, which persisted after 30 days of CKD induction in untreated rats (5.7 ± 1.5 and 3.5 ± 0.5 vs. 1.1 ± 0.2 and 1.0 ± 0.1, p < 0.05). This evidence concerns the gene ACTA1 and chronic kidney disease.