515. EFFECTS OF INHIBITION OF HEPERANASE BY SULPHATED MALTOHEXAOSE ON OVULATION, CORPORA LUTEA FORMATION AND PREGNANCY

Abstract

Heparan sulphate proteoglycans such as perlecan and collagen XVIII, are present in the follicular basal lamina, focimatrix and sub-endothelial basal laminas in follicles, but following the LH surge the follicular basal lamina and focimatrix are degraded. Heparanase, which degrades the glycosaminoglycan heparan sulphate, is upregulated in granulosa cells during ovulation. We examined the effects of heparanase inhibition by maltohexaose sulphate treatment on ovulation, formation and vascularisation of corpora lutea, and the establishment of pregnancy. Female twenty-five days old mice were treated with 0.3 mg (>25 mg/kg) maltohexaose sulphate or saline daily for four days from time 0 h and subjected to induction of ovulation by treatment with PMSG (5 IU at 0 h) and hCG (5 IU at 48 h) and mated with a fertile male. Mice were sacrificed at time 0 h, 48 h, 120 h and day 11 (relative to the first injection of PMSG) (n = 20 per group), and ovaries were collected and pregnancy status examined. One ovary was stained with haematoxylin and eosin to measure numerical densities of antral follicles and corpora lutea in the ovary, as well as volume density of luteal tissue. Immunohistochemistry for CD34 (endothelial cell marker) and perlecan (localized to sub-endothelial basal lamina) was conducted to quantify the degree of vascularisation of the corpora lutea. In control mice there was a reduction in the number of antral follicles with increasing age, but no effect of treatment with sulphated maltohexaose was observed on antral follicle development. Nor was there any effect of sulphated maltohexaose on corpora lutea formation, or embryo implantation. In addition, this treatment did not have any effect on the vascularisation of the corpora lutea. These findings suggest that heparanase activity may not be critical during the later stages of follicle growth, ovulation and formation of corpora lutea.