Experimental model
Compensatory Lung Growth in Autologous Lobar Implant: Experimental Study in Dogs

https://doi.org/10.1016/j.transproceed.2006.02.032Get rights and content

Abstract

Background

The best way to study compensatory lung growth (CLG) is in a transplant without rejection. Since immunosuppressive drugs may influence CLG, it is better to not use them. Therefore we studied CLG in a reimplant of only one lobe after its removal. The objective was to compare lobar transplant CLG with CLG after lobectomy.

Methods

Forty eight dogs were distributed in three groups: G1 = control, G2 = left cranial lobectomy, and G3 = left pneumonectomy with reimplantation of the caudal lobe. Five months after surgery the animals underwent lung scintigraphy and were sacrificed for morphometric study.

Results

There was no correlation between scintigraphy and lung mass or lung volume. There was both mass and residual volume CLG in the operated groups, both contralateral and ipsilateral to surgery. There was no compensation for total lung capacity or compliance in the remaining caudal lobe (G2) or the reimplanted caudal lobe (G3) at 5 months after surgery. There was more damage in the reimplanted lobe. As previous studies have shown that CLG starts with increased mass and residual volume and compliance is compensated later. This study seemed to document the beginning of CLG, with lung compliance being the limiting factor of CLG at 5 months.

Conclusion

There was CLG in both the reimplanted lobe and the contralateral lung, but compliance was still reduced. CLG was similar in both groups, but in the implanted lobe compliance was more prejudiced.

Section snippets

Materials and methods

We used 48 adult male dogs of undefined breed between (8 to 18 kg) which were provided by the UNESP Central Animal House and quarantined to assume that they were clinically healthy. The experiment was approved by the Ethics Committee on Animal Experimentation.

There were three experimental groups: control, G1 (n = 20), which were submitted to lung scintigraphy and then sacrificed for lung morphometry; lobectomy, G2 (n = 14) which underwent left cranial lobectomy and about 5 months later, lung

Results

The ischemia time varied from 57 to 85 minutes with maximum warm ischemia time of 4 minutes. G2 animals gained around 2.1 kg body mass between surgery and sacrifice; G3 animals gained only 0.7 kg. There was no significant difference in body mass between the three groups (P > .05).

G1, G2, and G3 left caudal lobe mean lung masses were 26.27 g, 35.20 g, and 43.19 g, respectively; significant differences were G1 < G2 < G3 (P < .001); RVs were 35.40 mL, 44.78 mL, and 48.64 mL respectively,

Left Caudal Lobe

Mean caudal lobe mass increased from G1 to G3, suggesting a higher mass compensatory growth in the reimplanted than in the remaining lobe of the lobectomized animals. In G3 we were able to measure the caudal lobe mass before reimplantation and therefore compare them at time of surgery and sacrifice. They were significantly higher at sacrifice even though they were drier due to bleeding. This mass in the reimplanted lobe was so large that it was similar to the whole left lung of the control

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