Effect of Mechanical Stimulation on Cell Proliferation in Mouse Epidermis and on Growth Regulation by Endogenous Factors (Chalones)

Abstract

Mechanical stimulation of dorsal mouse skin by skin massage or removal of the horny layer results in a mutually comparable increase in DNA-labelling and mitotic activity. However, only after injury such as removal of the horny layer hyperplasia develops. This phenomenon, called 'hyperplastic transformation' is characterized by a transient abolition of the epidermal GI chalone responsiveness. There is some indication that the susceptibility to a heat labile factor, probably the epidermal G2 chalone, is not affected. Skin massage neither interferes with the responsiveness to epidermal G1 chalone nor induces 'hyperplastic transformation'.Mouse tail epidermis shows a 'functional hyperplasia' and responds to the GI chalone. To explain these observations, it is assumed that the epidermal stem cell population is heterogeneous consisting of GI chalone-sensitive and G1 chalone-insensitive cells.

Concerted action of TGF-beta 1 and its type II receptor in control of epidermal homeostasis in transgenic mice.

“…A similar effect has been observed previously in mouse epidermis in response to gentle massage, as opposed to treatment with tumor promoters that induce overt hyperplasia (Bertsch et al 1976). Therefore, whatever the mechanisms for this elevated basal cell proliferation, one must also infer that there is increased keratinocyte turnover (differentiation and/or apoptosis) in the transgenic epidermis.…”

Annular Gap Junctions of the Equine Hoof Wall

“…However, not all epidermal tissues with increased Mitotic activity exhibit annular gap junctions. In tape-strip ped or sandpaper-removed epidermis, where there is known to be an increase in mitotic activity of basal cells [Bertsch et al, 1976], annular gap junctions have not been described.…”

Selective Cyclooxygenase-2 Inhibition Does Not Alter Keratinocyte Wound Responses in the Mouse Epidermis after Abrasion

“…Disruption of the cornified layer of the epidermis of SKH-1 hairless mice was performed as previously reported (Bertsch et al, 1976;Scholz et al, 1995). Briefly, mice were stroked 20 times across the back, from the hindquarters to the forelimbs, with silicon carbide ultra-fine 600-grit sandpaper (3M, St. Paul.…”

“…For example, involucrin is expressed by keratinocytes in the late spinous and granular layers. Mechanical disruption of the epidermal cornified layer by tape stripping or mild abrasion results in increased keratinocyte proliferation, transient epidermal hyperplasia, and altered keratinocyte differentiation characterized by the abnormal expression of involucrin and the transient induction of the keratin 6/keratin 16 heterodimer (Bertsch et al, 1976;Eckert et al, 1993;Hatta et al, 1997;Ekanayake-Mudiyanselage et al, 1998). The signals that trigger changes in keratinocyte proliferation and differentiation following wounding are not completely understood.…”

“…Mild mechanical abrasion results in epidermal injury in the absence of inflammation and consequently allows the dissection of the role of the two COX isoforms in keratinocyte biology in vivo following wound healing. Mild abrasive injury is associated with the induction of both transient hyperplasia and COX-2, suggesting that COX-2-dependent prostaglandin E 2 regulates this keratinocyte response following mild epidermal injury (Bertsch et al, 1976;Scholz et al, 1995). The expression and role of COX-2 during mild epidermal wounding has not been carefully investigated, however.…”