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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Denervation in man often results in shiny, dry, thin skin. A previous study has shown that the epidermis of glabrous skin in the rat becomes approximately 40% thinner within 1 week following sciatic nerve transection, but which nerve fiber type or types influence epidermal thickness is unknown. In this study, we compared the effects on the epidermis of selective sensory, motor, and sympathetic denervation. Protein gene product 9.5 and calcitonin gene-related peptide immunocytochemical staining were used to determine the extent of denervation of epidermis, dermis, and sweat glands in the footpads. Epidermal thickness of the glabrous plantar skin of the foot was measured. To verify the specificity and reliability of each animal model, the relevant regions of the peripheral nervous system were examined by light or electron microscopy or both. Epidermal thickness decreased significantly following sciatic nerve transection (58% of control, P < 0.05) and dorsal root ganglionectomy (59%; P < 0.05). The thickness also decreased following lumbar ventral rhizotomy (61%; P < 0.01), destruction of lumbar spinal motor neurons (66%; P < 0.05), and botulinum toxin-induced paralysis of the tibialis anterior and gastrocnemius muscles (70%; P < 0.05). A slight decrease followed dorsal rhizotomy (84%; P < 0.01). In contrast, no significant alterations in epidermal thickness were detected following sham operation and sympathectomy. Epidermal thinning was paralleled by reductions in the amounts of transcripts for glyceraldehyde-3-phosphate dehydrogenase and beta-actin. These results suggest that selective loss of both sensory and motor fibers to the hind limb can contribute to reducing epidermal thickness in rat foot glabrous skin.
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PMID:Sensory and motor denervation influence epidermal thickness in rat foot glabrous skin. 934 69

Several lines of evidence suggest that sensory nerves ending at the skin have profound influences on their target, the epidermis. To test the hypothesis, we examined the consequences of denervation on the paw skin of rats by eliminating its innervation. We investigated temporal changes of nerve degeneration, keratinocyte proliferation and differentiation, gene expression, and epidermal thickness. Nerve terminals in the epidermis began to degenerate within 24 h after denervation. All epidermal nerves were completely degenerated by 2 d. During the interval of nerve degeneration, there was a significant reduction of bromodeoxyuridine incorporation from 24 h of nerve injury (39 +/- 7% of the control side, p 0.01). By 2 d, there was a further reduction of bromodeoxyuridine labeling (11 +/- 8%, p < 0. 0001). The incorporation of bromodeoxyuridine remained depressed when the skin was denervated (35 +/- 11%, p < 0.01). Four days after eliminating skin innervation, the denervated epidermis became thinner than the control epidermis (70 +/- 8% of the control, p < 0. 01). Epidermal thinning was associated with a significant decrease in expression of glyceraldehyde-3-phosphate dehydrogenase and beta-actin transcripts (33 +/- 8% of the control epidermis from postoperative day 4, p < 0.001). Other aspects of keratinocyte differentiation, including the patterns of keratin expression, and programmed cell death, were unaltered by skin denervation. These data indicate that skin denervation is sufficient to influence keratinocyte proliferation and therefore epidermal thickness.
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PMID:Modulation of keratinocyte proliferation by skin innervation. 1050 44