Accelerative effect of topical Zataria multiflora essential oil against infected wound model by modulating inflammation, angiogenesis, and collagen biosynthesis

Abstract

Context: Zataria multiflora Boiss (Lamiaceae) essential oil (ZME) is believed to be a bactericide herbal medicine and might alleviate negative effects of infection.

Objective: This study evaluates the effects of an ointment prepared from ZME (ZMEO) on infected wounds.

Materials and methods: A full-thickness excisional skin wound was surgically created in each mouse and inoculated with 5 × 10⁷ suspension containing Pseudomonas aeruginosa and Staphylococcus aureus. The BALB/c mice (n = 72) were divided into four groups: (1) negative control that received base ointment (NCG), (2) positive control that daily received Mupirocin^® (MG), (3) therapeutic ointment containing 2% ZMEO and (4) therapeutic ointment containing 4% ZMEO, for 21 days. Wound contraction, total bacterial count, histopathological parameters, antioxidant activity, qRT-PCR analysis for expression of IL-1β, TNF-α, VEGF, IGF-1, TGF-β, IL-10, and FGF-2 mRNA levels were assessed on days 3, 7, and 14 following the wounding.

Results: Topical administration of ZMEO significantly decreased the total bacterial count and wound area and also expression of IL-1β and TNF-α compared to the control groups (p < 0.05) in all days. This could also increase significantly the expression of TGF-β, IL-10 IGF-1, FGF-2, and VEGF, and also angiogenesis, fibroblasts, fibrocytes, epithelialization ratio, and collagen deposition and improve antioxidant status compared to the control group (p < 0.05).

Discussion and conclusion: ZMEO accelerated the healing process of infected wounds by shortening the inflammatory factors and increasing proliferative phase. Applying ZMEO only and/or in combination with chemical agents for the treatment of wound healing could be suggested.

Keywords: Infected wound healing; antimicrobial properties; inflammatory cytokines; thymol.

Figure 1.

GC-MS chromatogram of the essential oil of Zataria multiflora.

Figure 2.

The effects of topical administration of ZMEO on (B) wound contraction rate and (C) tissue bacterial count (CFU/g) in different days. Superscripts (a–d) indicate significant differences in same day at p < 0.05.

Figure 3.

Immunohistochemical staining for angiogenesis:; (A) NCG group, (B) MG group, (C and D) 2 and 4% ZMEO-treated groups. See elevated angiogenesis in ZMEO-treated group (arrows) on day 7 after wound induction. CD 31 staining, 400×.

Figure 4.

Cross section from wound area: (A) NCG group, (B) MG group, (C and D) 2 and 4% ZMEO-treated groups. Note well-formed collagen deposition in cross sections from ZMEO-treated animals on day 7 after wound induction (first row), which is significantly increased on day 14 after injury (second row). The third row represents the software analyze for collagen intensity. The cross sections from animals in ZMEO-treated groups exhibited condense collagen deposition versus NCG and MG groups. Masson-trichrome staining and fluorescent staining for collagen, 400× magnification.

Figure 5.

Cross section from wound area: (A) NCG group, (B) MG group, (C and D) 2 and 4% ZMEO-treated groups. See well re-epithelialization in ZMEO-treated animals. The re-epithelialization initiated on day 7 after wound induction in ZMEO-treated animals. However, the cross sections from NCG and MG groups are not representing epithelialization. Note well-organized dermis and complete epithelialization with well-formed papillae in ZMEO-treated animals in comparison to NCG and MG groups. Masson-trichrome staining, 100×.

Figure 6.

The effects of topical application of ZMEO on gene expression. Superscripts (a–d) indicate significant differences in same day at p < 0.05.

Figure 7.

The effects of topical application of ZMEO on antioxidant properties. Superscripts (a–d) indicate significant differences in same day at p < 0.05.