Effect of poly-L-lactic acid and polydioxanone biostimulators on type I and III collagen biosynthesis

Abstract

Objective: Safe, effective, and biocompatible minimally invasive procedures with the potential to stimulate collagen production have been made to recover dermal thickness and skin quality. The main of this animal model experiment was to observe the effect of poly-L-lactic acid (PLLA) and polydioxanone (PDO) biostimulators in collagen I and III after hypodermal injection.

Methodology: Sixteen adult female rats (Wistar) were randomized into four groups and had dorsal treatment with: G1: hypodermic subcision (HS) only; G2: HS and PLLA hypodermic injection (HI), G3: HS and PDO HI; G4: Control, with no treatment.

Results: In histochemical, it was observed hypodermal and dermal tissue in more organized thickness in G3 and in G4 when compared to G1 and G2. There was few difference in G1 compared to G4. The tissue of G2 showed irregularities in the arrangement of collagen fibers, less defined structure and lower distribution of type I collagen compared to the other groups. There is a greater tendency for the proportions of type III collagen among tissues treated with both biostimulators (G2 and G3). PLLA and PDO had relatively similar percentages of collagen when compared to G4. The amount of type I collagen was higher in tissues treated with subcision, while type III collagen was higher in tissues treated with both biostimulators.

Conclusion: G3 showed better performance in collagen production, although small, when compared with G2.

Keywords: biostimulators; collagen; polydioxanone; poly‐L‐Latic acid; rejuvenation; skin; subcision.

FIGURE 1

Flowchart of the experimental design of the study for induction of collagen formation in mice with subcision, subcision + PLLA, subcision + PDO, and no Treatment. G1, group 1; G2, group 2; G3, group3; G4, group 4; HE, hematoxylin and eosin; PDO, polydioxanone; PLLA, poly‐L‐lactic acid.

FIGURE 2

3 × 3 cm area demarcation in the posterior dorsal region for the treatment.

FIGURE 3

Tissue excision 30 days after experiment.

FIGURE 4

Tissue sections of the posterior dorsal region after 30 days of subcision, application of biostimulators and control group in HE stains. (A) Subcision with 22G Cannula (G1); (B) Subcision and treatment with 0.5 mL of PLLA in a single session (G2); (C) Subcision and treatment with 0.5 mL of PDO in a single session (G3); (D) Control with no treatment (G4). HE, hematoxylin–eosin; PDO, polydioxanone; PLLA, poly‐L‐lactic acid.

FIGURE 5

Tissue sections of the posterior dorsal region of mice after 30 days of subcision, application of biostimulators and control group in Picrosirius staining and visualized under polarized light. (A) Subcision with 22G Cannula (G1); (B) treatment with 0.5 mL of PLLA in a single session (G2); (C) treatment with 0.5 mL of PDO in a single session (G3); (D) control (G4). PDO, polydioxanone; PLLA, poly‐L‐lactic acid.

FIGURE 6

Proportion of red (type I collagen) green (type III collagen) staining in tissue sections of the posterior dorsal region of mice after 30 days of subcision, application of biostimulators and control group. G1: Subcision with 22G Cannula; G2: treatment with 0.5 mL of PLLA in a single session; G3: treatment with 0.5 mL of PDO in a single session; G4: control. The results are presented as average and standard deviation. PDO, polydioxanone; PLLA, poly‐L‐lactic acid.