Effects of calcium deficiency and calcium supplementation on gastrectomy-induced osteopenia in the young male rat.
BACKGROUND
Surgical removal of the stomach (gastrectomy, Gx) induces osteopenia. In this study we compared the osteopenic effect of Gx with that induced by calcium (Ca) deficiency.


METHODS
Young male rats were subjected to Gx and/or low Ca diet (-Ca). A group of Gx rats received standard diet + oral Ca supplementation (+Ca). The rats were killed at various times after the operation/start of treatment (longest time 12 weeks). After 8 weeks on low Ca diet, the blood Ca2+ concentration was lowered slightly in both Sham-operated and Gx rats. The calvariae were subjected to transillumination analysis and quantitative histomorphometry. Also the tibiae were subjected to histomorphometry.


RESULTS
Transillumination of the calvariae revealed extensive bone loss in the rats that had been subjected to Gx and/or low Ca diet. Gx + Ca induced the same bone loss as Gx alone. These observations were later confirmed in quantitative terms by histomorphometry (Sham-Ca 56%, Gx 35%, Gx + Ca 32%, Gx - Ca 58% less bone area than in Sham). The osteopenia induced by Gx + low Ca diet seetned more rapid in onset than that induced by Gx or low Ca diet alone. Tibiae from Gx rats and rats given a low Ca diet displayed a reduced trabecular bone volume (Sham-Ca 27% remaining, Gx 36%, Gx + Ca 44%, Gx - Ca 17%) and reduced trabecular number (Sham-Ca 44% remaining, Gx 41%, Gx + Ca 56%, Gx - Ca 33%). The trabecular thickness was reduced in the Gx rats and Gx - Ca rats (Gx 78% remaining, Gx - Ca 63%) but not in Sham-operated rats receiving a low Ca-diet (95% remaining).


CONCLUSIONS
Although the pattern of osteopenia was qualitatively quite similar in Gx rats and Ca-deficient rats, in quantitative terms the low Ca diet was more detrimental to bone than Gx. Ca deficiency induced a similar degree of osteopenia in both Sham and Gx rats. Ca supplementation failed to prevent the Gx-induced osteopenia.
Lehto-Axtelius
D
D
Dept. of Radiology, Centre for Oral Health Sciences, Malmö University, Sweden.
Surve
V V
VV
Johnell
O
O
Håkanson
R
R
D000704:Analysis of Variance; D000818:Animals; D015519:Bone Density / Q000502:physiology; D001851:Bone Diseases, Metabolic / Q000209:etiology* / Q000473:pathology*; D002118:Calcium / Q000172:deficiency*; D002136:Calcium, Dietary / Q000494:pharmacology*; D004032:Diet; D004195:Disease Models, Animal; D005269:Femur / Q000254:growth & development / Q000473:pathology; D005743:Gastrectomy; D007150:Immunohistochemistry; D008297:Male; D011336:Probability; D051381:Rats; D017207:Rats, Sprague-Dawley; D012680:Sensitivity and Specificity; D013977:Tibia / Q000254:growth & development / Q000473:pathology
D002136:Calcium, Dietary; D002118:Calcium