Heparin protects local skin microcirculation in 210 minutes-long intravital microscopy observations under general anaesthesia.
Prolonged immobilization of severely ill, bed-ridden patients results in formation of pressure ulcers following inappropriate tissue blood perfusion, and local activation of leukocyte - endothelial cell interactions (L/EC). Various treatment modalities were implemented to improve local microcirculation with controversial results. The aim of our study was to investigate the influence of heparin and buflomedil, drugs improving the microcirculation, on local skin blood perfusion using intravital fluorescent microscopy (IVM) technique.


METHODS
Experiments were carried out on 24 male hairless mice under inhalatory isofluran anaesthesia. Intravenous injection of FITC-dextran (150 kD, 5%) allowed to visualize capillaries during IVM, after immobilisation of hind limb, in an observation chamber. Observations were performed after i.v. injection of heparin (66 IU/kg b.w., n = 8) or buflomedil (6 mg/kg b.w., n = 8) 30, 120 and 210 minutes after chamber installation. Observations were recorded in 30 sec sequences on S-VHS tapes and evaluated using special software. Functional capillary density (FCD), defined as a total length of red cells perfused capillaries per observation field (expressed in cm/cm(2)), postcapillary venule diameters, and number of sticking leukocytes per 0.2 mm vessel length during 30 sec observation time, served as parameters of skin blood perfusion and activation of L/EC interactions.


RESULTS
A statistically significant decrease of FCD from 152.7 +/- 38.5 to 100.7 +/- 36.7 cm/cm (2) (p<0.05) was observed in control animals during 210 min lasting observation. Administration of heparin prevented decrease in FCD occurring in control animals during intravital microscopy, whereas buflomedil was found ineffective. Both drugs induced a nonsignificant reduction in the number of sticking leukocytes, whereas no changes in postcapillary venule diameters could be observed.


CONCLUSIONS
The results suggest a protective effect of heparin in clinical therapeutic doses against impairment of skin perfusion during IVM. This observation may justify a trial on the effects of heparin in prevention of development of pressure ulcers.
Szczesny
G
G
Institute of Surgical Research, Klinikum Grosshadern, Munich, Germany. szczesny@cmdik.pan.pl
Veihelmann
A
A
Nolte
D
D
Olszewski
W L
WL
Messmer
K
K
D000818:Animals; D000925:Anticoagulants / Q000008:administration & dosage; D002196:Capillaries / Q000187:drug effects* / Q000502:physiology; D002448:Cell Adhesion / Q000187:drug effects; D006493:Heparin / Q000008:administration & dosage*; D007275:Injections, Intravenous; D007962:Leukocytes / Q000187:drug effects; D008297:Male; D051379:Mice; D008812:Mice, Hairless; D008833:Microcirculation / Q000187:drug effects* / Q000502:physiology; D008856:Microscopy, Fluorescence; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage; D011759:Pyrrolidines / Q000008:administration & dosage*; D012867:Skin / Q000098:blood supply*
D000925:Anticoagulants; D010975:Platelet Aggregation Inhibitors; D011759:Pyrrolidines; D006493:Heparin; C010651:buflomedil