Date of Award
Master of Science (MS)
Maturation of the collagen fiber involves aggregation of the tropocollagen molecule through increasing numbers of inter- and intramolecular crosslinkages. Maturation is reflected in the transition of soluble to insoluble collagen. An experimental model, lathyrism, induced by beta-aminopropionitrile (BAPN), alters the normal collagen bonding and produces an increase of the saline-soluble collagen. Conflicting reports have been made concerning bond alteration of the insoluble fiber by BAPN, reverting the collagen to a more soluble state. The prepartum rat uterus, with collagen of a high turnover or maturation rate, was used to determine the contribution of the insoluble collagen fiber to the lathyric collagen.
Ten albino rats were injected with the labeled amino acid L-proline-H-^ on the seventeenth day of gestation to label the collagen of the uterus. Thirty-six hours later half the animals were injected with BAPN while the other half served as controls. Biopsies of the uterine horns were taken from anesthetized rats at two, three and four hours post-BAPN injection. Tissue from one horn was fixed immediately in buffered neutral 10% formalin while that from the other horn was extracted with cold 1 M saline for 24 hours prior to fixation. The effect of cold saline on the uterineinsoluble collagen was compared in control and BAPN injected groups using histological stains and autoradiograph techniques .
Microscopic evidence of tissue shrinkage caused by hypertonic 1 M saline extraction was noted. It was felt that this shrinkage was responsible for the high silver grain counts noted in most autoradiographs of extracted tissue. The cytoplasm of the mucosal epithelium of BAPN-treated tissue was more acidophilic than the control tissue. Disruption of reticular fibers and nets was noted in saline extracted experimental tissue when compared to extracted control tissue.
A decrease in the average silver grain counts was noted in non-extracted and extracted experimental tissue when compared to control tissue. This finding suggested a possible action of BAPN on uterine collagen before the first biopsy was taken. However, no evidence was obtained suggesting that BAPN caused the mature collagen of the prepartum rat uterus to revert to a saline-soluble form.
Ingli, James E., "An Autoradiographic Study of the Effect of Beta-Aminopropionitrile on the Prelabeled Mature Collagen of the Prepartum Rat Uterus" (1967). Theses and Dissertations. 3997.