Age-Related Palatal Wound Healing: An Experimental In Vivo Study

Abstract

We assessed age-related excisional palatal mucoperiosteal wound closure in rats. A 4.2 mm diameter punch was used to create a secondary healing defect in the palate of Wistar rats. Study group—21, 18-month-old vs. control 21, 2-month-old males. The 2-dimensional area, maximum length and width of the soft tissue defect served as clinical outcome parameters. The dynamics of the initial three healing weeks were assessed. Semi-quantitative histomorphometric analysis of inflammation and myofibroblasts served for the evaluation of the inflammatory and proliferative wound healing phases. Complete wound closure was faster in the old rats. A dimensional related wound closure was observed in the young rats versus a symmetrical wound closure in the old rats. Inflammatory response was significantly delayed and of lower intensity in the old rats. Myofibroblastic response, representing the proliferative stage, was delayed and of lower intensity in the old rats, albeit not statistically significant. Reduced initial tissue damage due to decreased and delayed inflammatory response in the old rats ultimately led to faster clinical wound healing compared to the young rats, despite a statistically non-significant lower proliferative response in the old rats.

The Impact of Corticosteroid Administration at Different Time Points on Mucosal Wound Healing in Rats: An Experimental Pilot In Vivo Study

“…This suggests that the level of inflammation needed for optimal healing is lower in mucosal tissue. The previous statement was supported by an earlier study demonstrating faster clinical wound healing in the old male rats than the young rats due to diminished and delayed inflammatory response in the aged rats [ 4 ].…”

“…After removing the soft tissue, a circular area of denuded bone (without periosteum) was left for secondary healing [ 32 ]. The protocol of surgery, aftercare, and sacrificing techniques, as well as macroscopic and microscopic assessments, are described in detail in our previous publication [ 4 ]. Animals were randomly sacrificed at one week (W1), two weeks (W2), and three weeks (W3) post-operatively.…”

“…The palate specimens were calibrated using a 15 mm long University of North Carolina color-coded periodontal probe with millimeter markings (UNC-Hu Friedy Manufacturing Inc., Chicago, IL, USA). The specimens were photographed in a standardized manner using a Cannon EOS 550D camera (Canon Inc., Tokyo, Japan) immediately after tissue harvesting (W0) at one week (W1) and immediately after sacrifice before maxillary harvesting for histological examination, W2 and W3 [ 4 ].…”

“…The palatal excisional wound in the rat is a reproducible model for evaluating clinical and histological outcomes. Many studies used this model to investigate factors that might enhance intra-oral wound healing [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ], such as topical use of biomaterials [ 5 , 6 , 7 , 8 ], antimicrobials [ 9 ], and growth factors [ 10 ]. Other factors that have been found to impact wound healing, probably by modulating the inflammatory process, include age and gender [ 4 , 11 , 12 , 13 ], systemic treatment with corticosteroids [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ] or retinoids [ 15 ], and pathological conditions such as Xerostomia [ 22 , 23 , 24 ] and diabetes mellitus [ 25 ].…”

Observation of Palatal Wound Healing Process Following Various Degrees of Mucoperiosteal and Bone Trauma in a Young Rat Model

“…Acellular dermal matrix (ADM) has been described as an adjunct in primary cleft palate repair to reduce the fistula rate in several retrospective studies [ 14 , 19 , 20 ]. In our research, we further estimated the role of ADM in treating bone denudation and alleviating inhibition of maxillary growth.…”