33 pregnant sheep subjected to injections – then had their fetuses delivered prematurely – and hearts of the fetuses removed whilst still alive

Tare, M, Bensley, J, Moss, T, Lingwood, B, Kim, M, Barton, S, Kluckow, M, Gill, A, De Matteo, R, Harding, R, Black, M, Parkington, H, & Polglase, G 2014, ‘Exposure to intrauterine inflammation leads to impaired function and altered structure in the preterm heart of fetal sheep’, Clinical Science, 127, 9: 559-569.

Institution: Monash University

Aim

The study aimed to investigate the effects on the heart function and heart muscle cells of a premature fetus after inducing intrauterine inflammation.

The Experiment

The study was conducted in order to relate back to human preterm births and how infant babies are affected with heart conditions if their mothers are exposed to chorioamnionitis (intrauterine inflammation).

In the experiment a total of 33 ewes and their fetuses were used. The study involved an injection of a bacterial solution (or saline solution) into the amniotic fluid of ewes on day 120 of their gestation (full term is 147 days).

On the 7th day after the injection the fetuses were delivered prematurely via caesarean sections and the hearts of the fetuses were removed whilst still alive to ensure the heart continued to beat for further analysis. Ewes were killed after they had provided the fetuses for study.

Results

Arrhythmias (irregular heart beats) occurred in 5 of 6 hearts that were exposed to the bacterial injection. The blood flow velocity in arteries was higher in the hearts of lambs that had been subjected to intrauterine inflammation. Different weights of left and right ventricles compared to normal were found in the exposed lambs. Also the exposed lambs had lower heart contraction capabilities as well as pressure irregularities of the ventricles.

Conclusions

The study concluded that intrauterine inflammation can affect the heart of a fetus in a number of ways that compromise post-natal cardiac performance. The heart is more vulnerable to damage and arrhythmias and long-term dysfunction after pre-natal exposure to the induced inflammatory condition.

Was the study warranted?

The article introduces a number of studies that already showed results with reduced cardiac performance after intrauterine inflammation. The article offers no treatment or new ideas to be tested, but rather confirms previous studies that have already received positive results. Previous studies have been conducted even on sheep in this area, involving the same injecting substance to elicit intrauterine inflammation. This study similarly reported cardiac contractile dysfunction (Seehase et al. 2011). So why conduct a close to identical study where animal lives are sacrificed if it provides no treatment and only the same conclusions?

Was it warranted that the ewes be killed after they had delivered the fetuses? Their hearts weren’t used in experiments and ewes can survive a caesarean section.

Reference: Seehase, M, Gantert, M, Ladenburger, A, Garnier, Y, Kunzmann, S, Thomas, W, Wirbelauer, J, Speer, C, & Kramer, B 2011. ‘Myocardial response in preterm fetal sheep exposed to systemic endotoxinaemia’, Pediatric Research, 70, 3: 242-246.

Funding

This experiment was funded by the National Health and Medical Research Council of Australia, the Research Foundation of Cerebral Palsy Alliance, and the North Shore Heart Research Foundation.

What Can You Do?

Please write to Professor Margaret Gardner asking that Monash University no longer fund animal-based experiments. Ask why the ewes in this particular experiment were sacrificed when they were capable of living a perfectly healthy life.

Professor Margaret Gardner
Vice-Chancellor and President
Monash University
Victoria 3800, Australia
Email: Andrea.Goff@monash.edu (Executive assistant)

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