EXPERIMENTAL STUDY ON RENAL HYPERTENSION

Abstract

Numbers of experimental and clinical studies have been contacted on renal hypertension since the 18th century, but the causative mechanism, appropriate diagnosis and proper method of therapy of the disease have not yet made clear.
Using 120 dogs, I artificially produced renal hypertension by Goldblatt's technique, studied the blood pressure responses and made histological examination of the kidney. The dogs were divided into two groups.
The first group: The first group includes those dogs whose left renal arteries were constricted by polyethylene tubes and the right kidneys were removed.
The second group: The second group includes those dogs whose left renal arteries were constricted in the same way, but whose right kidneys were intact.
They were sacrificed at 1, 3, 5 days, and 1, 2, 3, 4, 6 and 8 weeks after the operation.
As a result, I came to the following conclusions:
1) Concerning the changes in the systolic blood pressure in the renal artery stricture, the first group showed a severe hypertension (40-60mmHg), whereas the second showed a mild hypertension (20-30mmHg), observable only in half the number.
2) As to histological changes of the constricted kidney in the first group, the lesions of tubules and interstitial tissue, which seemed to have resulted from the operation, were observed 1 to 3 days after the treatment; changes were observed in the glomerulus, Bowman's capsules and tubules 1 week after the treatment in the interstitial tissues 2 weeks after the treatment; ischemic and sclerotic changes in the blood vessels of the kidney 3 weeks after the treatment. These changes tended to increase with the passage of time. They were similar to the clinical bilateral renal artery stenosis.
3) In the constricted kidneys of the second group, mild changes were observed in the tubules, interstitial tissues and glomerulus 1 to 3 days after the treatment, and in the Bowman's capsules and blood vessels 1 week after the treatment. They were not so severe as to cause a degeneration. This suggested that they were not hypertensive changes but ischemic changes.
4) In the contralateral kidneys of the second group, the sclerotic changes were observed in the small blood vessels 1 week after the treatment, and in the both small and medium blood vessels and renal parenchyma with the passage of time.
5) In the first group, the changes in the granularity were observed to increase in the juxta-glomerular cells of the constricted kidney 5 days after the treatment, the kidney became greatly granulated, reaching the highest point 3 weeks after the treatment. After that the granulation was reduced, but a slight hypergranularity continued till 8 weeks after the treatment.
In the second group, the clipped kidney had a hypergranularity right after the operation, but the granules tended to decrease from 4 weeks after the treatment and they disappeared all at 8 weeks.
On the other hand, there was a decrease in their granularity of the juxtraglomerular cells in the contralateral kidney at 2 weeks, but most of them showed the normal granules at 8 weeks.