Premium
The Effect of Insulin‐Like Growth Factor‐I and Human Growth Hormone on Periodontal Ligament Fibroblast Morphology, Growth Pattern, DNA Synthesis, and Receptor Binding
Author(s) -
Blom Søren,
Holmstrup Palle,
Dabelsteen Erik
Publication year - 1992
Publication title -
journal of periodontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.036
H-Index - 156
eISSN - 1943-3670
pISSN - 0022-3492
DOI - 10.1902/jop.1992.63.12.960
Subject(s) - periodontal fiber , growth factor , dna synthesis , receptor , connective tissue , thymidine , endocrinology , medicine , cell growth , growth inhibition , cell culture , fibroblast , insulin like growth factor , chemistry , somatomedin , microbiology and biotechnology , biology , dna , biochemistry , genetics , dentistry
R epopulation of the detached root surface by cells from the periodontal ligament (PDL) is a prerequisite for new attachment formation. Stimulation of PDL‐cell growth may therefore serve as an essential method to enhance formation of new attachment. Studies have demonstrated that insulin‐like growth factor‐I (IGF‐I) has a mitogenic effect on fibroblasts originating from various connective tissues and cell‐lines. Further, human growth hormone (hGH) is known to regulate the plasma concentration of IGF‐I and to mediate cellular biological effects. In the present study we examined the effect of IGF‐I and hGH on morphology, growth pattern, and DNA synthesis. The expression of IGF‐I and hGH receptors on the surface of cultured PDL fibroblasts is also described. A primary fibroblastic cell line was established from rat PDL tissue, and blind, photographic recordings of morphology and growth pattern, as well as incorporation of [ 3 H]thymidine in cellular DNA, was carried out in the presence and absence of IGF‐I and hGH. The presence of specific membrane receptors was investigated by binding of [ 125 I]IGF‐I and [ 125 I]hGH. The analysis of photographs showed that IGF‐I and hGH had no effect on morphology and growth pattern. Incorporation of 3H‐thymidine, however, was increased in a dose‐dependent manner by IGF‐I, whereas hGH alone or in combination with IGF‐I produced no dosedependent response. Maximum effect (% of control) on DNA synthesis was 176% for IGFI and 91% for hGH. The mitogenic effect of IGF‐I was not enhanced in the presence of hGH, on the contrary, incorporation of [3H]‐thymidine was perhaps slightly depressed by all tested concentrations of hGH. [ 125 I]IGF‐I was displaced in a concentration‐dependent manner by unlabeled IGF‐I, whereas no specific binding was found for [125I]hGH. Maximum specific binding was 5.8% of added IGF‐I, and half maximal binding was found at a concentration of 10 to 100 ng/ml IGF‐I. This study demonstrates that IGF‐I can stimulate the DNA synthesis of PDL fibroblasts, likely via binding to high affinity cell surface receptors. The effect of IGF‐I was not enhanced by hGH and no effects on the morphology or growth pattern were observed. J Periodontol 1992; 63:960–968.