Neutrophil depletion in the early inflammatory phase delayed cutaneous wound healing in older rats: improvements due to the use of un-denatured camel whey protein

Hossam Ebaid

doi:10.1186/1746-1596-9-46

Abstract

BackgroundWhile it is known that advanced age alters the recruitment of neutrophils during wound healing, thereby delaying the wound healing process, little is known about prolonged wound healing in advanced ages. Thus, we investigated the correlation of neutrophil recruitment with healing events, and the impact of whey protein (WP) on neutrophil activation.MethodsThe animals were allocated into wounded young group, wounded older group and wounded older rats with daily treatment of WP at a dose of 100 mg/kg of body weight.ResultsOur results pointed to a marked deficiency in the number of neutrophils in the wounds of older rats, which was accompanied with impairment of the healing process. In the group of older rats, phagocytic activity, as tested by fluorescence microscopy, declined throughout the first 24 hours after wounding. Both the neutrophil number and the phagocytic activity recovered in older rats which received WP supplementation. Interestingly, WP was found to significantly up-regulate the MIP-1α and CINC-1 mRNA expression in old rats. On the other hand, the wound size in older rats was significantly higher than that in younger ones. Blood angiogenesis was also significantly delayed in the older group as opposed to the young rats. WP, however, was found to return these indices to normal levels in the older rats. Proliferation and epidermal migration of the keratinocytes and the collagen deposition were also returned to the normal rates.ConclusionsThis data confirms the critical role of neutrophil recruitment in the early inflammatory phase of wound healing in older rats. In addition, WP protein was used to improve neutrophil function in older rats, healing events returned to a more normal profile.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2100966986117779.

Highlights

While it is known that advanced age alters the recruitment of neutrophils during wound healing, thereby delaying the wound healing process, little is known about prolonged wound healing in advanced ages
Wound healing capacity is known to decline with increasing age [5,6] and it has been suggested that agemediated defects in early neutrophil recruitment may alter the dynamics of the inflammatory phase of wound healing [7]
We studied the effect of whey protein (WP) on neutrophil recruitment during wound healing in rats of advanced age

Summary

Introduction

While it is known that advanced age alters the recruitment of neutrophils during wound healing, thereby delaying the wound healing process, little is known about prolonged wound healing in advanced ages. In the inflammatory phase of wound healing, neutrophils are responsible for microbial clearance in the region of the wound region, playing a role in antigen presentation, phagocytosis and the production of inflammatory cytokines and growth factors [1,2]. The persistently high levels of pro-inflammatory cytokines in the wounds of the elderly induce high levels of matrix metalloproteinases (MMPs). This suppresses growth factors, receptors and matrix proteins essential for healing [13,14]. Chemoattractants, which direct the transit of leukocytes out of the mainstream of the blood and into tissues at sites of inflammation, are reduced This is significant since neutrophils are uniquely sensitive to a vast array of chemoattractants including MIP-1a, MIP-1b, MIP-2, KC, and others [16]

Methods

Results

Conclusion