Development and reagibility of the micro-circulation in the granulation tissue after distance osteosyntheses: An experimental analysis of laser doppler flowmetry under the influence of CGRP
Konrad Wolf, Janos Hamar, Eduard Höcherl, Claus Pfister

There are only few animal models available that can be considered suitable for investigating functional junctions of the de novo vessels in granulation tissue and  determining the ability of the micro-circulation reaction to a stimulus such as neuropeptide hormone dosage.
The Laser-Doppler-Flowmetry method  (LDF) was applied in a newly developed Distance-Osteosynthesis-Model of the rabbit tibia, which builds a sufficient amount of granulation tissue in its interfragmental gap.

The relative flow was measured and expressed as a Blood Perfusion Unit (1 BPU = 0,2 mV). The Anova-test and Student t-test were used for statistical purposes.

The following parameters: Relative Deviation of Blood Flow, Time to Peak, Half time Recovery and Peripheral Resistance were employed as variables of the micro-circulation. Therefore, the deviation rise of the bone perfusion in time appears significantly different. A reaction to CGRP stimulation (CGRP 0,5 microg / kg body weight), from the beginning of  the 10th post-operative day, is clearly evident. Time To Peak in the granulation tissue appears already on the 10th post-operative day which has the same steady dynamics as the reference measurement of the femur tissue. Half Time Recovery demonstrates statistically as seen at beginning of the 10th day, similar dynamics as the one seen in the regular tissue. The peripheral resistance in the early phase (Day 0 to 5) is capable of compensating only with an adjustment in the change of the blood pressure, however, not with a vessel enlargement (Quotient >1). 

On the 10th day a shift in the quotient build up toward the value of 1 (one) takes place. Then from the 15th day on, the quotient build up remains uniform < 1 (one).

Due to the varying differentiation degree capability of the mesenchymal pluripotent cells which the CGRP-receptors of the granulation tissue growth already posess in the early phase stage, the dynamics of micro-circulation and microcirculation reaction capability can be seen as a prognostic factor rendered accessibly to an individual measurement.

Keywords: distance osteosyntheses, microcirculation, laser-doppler-flowmetry, calcitonin gene-related peptide

Applied Cardiopulmonary Pathophysiology 9: 333-342, 2000

Konrad Wolf, M.D.
Department for Traumatology
Hand and Reconstructive Surgery
Hospital Munich Schwabing
Kölnerplatz 1
D-80804 München