Bone mineral metabolism in T lymphocyte-deficient and -replete strains of rat.
The immune and skeletal systems are known to interact. We have repeatedly shown that in contrast to in vitro data, the administration of T lymphocyte immunosuppressants, such as cyclosporin A, leads to an increase in bone resorption and a high turnover osteopenia. The purpose of this study was to characterize the bone metabolism of the T lymphocyte deficient Rowett athymic homozygous (rnu/rnu) nude rat. We wished to determine whether these rats share the bone abnormalities of cyclosporin A-treated rats. Eleven 10-week-old Sprague-Dawley rats and 12 similarly aged nude rats were studied over a 4-week period. Metaphyseal cancellous bone histomorphometry was similar in the two groups of rats and only differed with regard to percentage eroded perimeter (lower in nude rats, p = 0.0008) and longitudinal growth rate (49% lower in nude rats, p < 0.001). The nude rats had less body mass (p < 0.001) but nevertheless gained the same percentage of their body weight over the study period. The athymic rats had lower levels of serum, 1,25-dihydroxyvitamin D (p < 0.014) and serum osteocalcin(p < 0.009), and at the age of 14 weeks the nude rats had lower concentrations of serum creatinine (p = 0.001) and blood ionized calcium (p = 0.0002), yet serum PTH was similar throughout. RNA isolated from the contralateral tibias revealed that the nude group had lower steady-state levels of osteocalcin mRNA despite similar rates of bone formation. In its entirety, the data suggest that T cell deficiency per se is not necessarily associated with high turnover osteopenia.
Buchinsky
F J
FJ
Department of Endocrinology and Metabolism, Albert Einstein Medical Center, Philadelphia, Pennsylvania, USA.
Ma
Y
Y
Mann
G N
GN
Rucinski
B
B
Bryer
H P
HP
Paynton
B V
BV
Jee
W S
WS
Hendy
G N
GN
Epstein
S
S
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001806:Blood Urea Nitrogen; D001835:Body Weight / Q000502:physiology; D015519:Bone Density; D001846:Bone Development; D001842:Bone and Bones / Q000033:anatomy & histology; D002117:Calcitriol; D003404:Creatinine / Q000097:blood; D008231:Lymphopenia / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008903:Minerals / Q000378:metabolism*; D015675:Osteocalcin / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D051381:Rats; D011923:Rats, Nude; D017207:Rats, Sprague-Dawley; D013601:T-Lymphocytes / Q000473:pathology
D001786:Blood Glucose; D008903:Minerals; D010281:Parathyroid Hormone; D015675:Osteocalcin; D003404:Creatinine; D002117:Calcitriol