Abstract
To determine the effect of age and sex on the rise in pulmonary artery(PA)pressure(P)and on morphologic changes in the PV bed in response to chronic hypoxia, 12 Sprague-Dawley infant rats (I-rats)and 11 adult rats(A-rats)were placed in hypobaria(air at 380 mmHg)for 1 month. The I-rats, 8 male(M)and 3 female(F)were 8 days old(mean weight=10 grams); the A-rats, 7M and 4F, 3 months old (mean weight=280 grams). After exposure, indwelling PA and aortic(Ao)catheters were inserted under pentobarbitol anesthesia and the next day unanesthetized pressure measurements were recorded. The rats were sacrificed and their lungs analysed(after injecting the PA tree with barium-gelatin and the parenchyma with formalin)by 3 structural features: 1)extension of muscle into small arteries(EMSA), 2)percentage wall thickness of peripheral arteries(%WT)and 3)alveolar artery ratio(A/A). A rise in mean PAP to 51±5.1(compared with 16.6±1.1 in C-rats)observed in I-rats was similar in AM-rats, but mean PAP in AF-rats was lower(29.6± 2.1, p < 0.03); AoP was unchanged in all. Increased EMSA, %WT and A/A were found in I-rats and A-rats compared with C-rats(p<0.005); however AF-rats compared with AM-rats showed less increase in %WT(p<0.05). Thus, after chronic hypoxic exposure, adult female rats had developed milder PA hypertension associated with less medial hypertrophy.
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Rabinovitch, M., Murray, K., Aronovitz, M. et al. 148 AGE AND SEX AS DETERMINANTS OF THE PULMONARY VASCULAR (PV)RESPONSE TO CHRONIC HYPOXIA IN RATS. Pediatr Res 12 (Suppl 4), 388 (1978). https://doi.org/10.1203/00006450-197804001-00153
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DOI: https://doi.org/10.1203/00006450-197804001-00153