Long-term regression of experimental endometriosis in a rat model treated with local application of levonorgestrel-loaded biodegradable microspheres

Yuan P, Peng Yuan, B. Chen, Chen B, Biliang Chen, Yuxin Huang, Huang Y, Yanhong Huang, Xin X, Xiaoyan Xin
Human Reproduction · 2012 · vol. 27(7) , pp. 2089–2095 · doi:10.1093/humrep/des142 · PMID:22563024 · W2098245890
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Local application of levonorgestrel-loaded microspheres induced long-term regression of endometriotic cysts in rats for one year, comparable to GnRH agonist treatment.

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Abstract

BACKGROUND: A previous study demonstrated that local application of levonorgestrel-loaded polylactic acid microspheres (LNG microspheres) resulted in significant regression of endometriotic cysts in a rabbit model for 6 months without disturbing the metabolic parameters or ovarian function. In order to investigate the feasibility of local application of LNG microspheres as a long-term maintenance treatment for endometriosis, the suppressive effect of a single intra-cystic injection of LNG microspheres was studied for 1 year in a rat model. METHODS AND RESULTS: Twenty four rats with experimental endometriotic cysts were randomized to be treated with a single intra-cystic injection of LNG microspheres (n = 8); 6-month GnRH agonist (GnRHa, n = 8) or control (n = 8). Intra-cystic injection of LNG microspheres and GnRHa treatment caused comparable regression and atrophy in endometriotic cysts in the first 6 months. Compared with the control, the wet weight of the endometriotic cysts was significantly lower in both groups at Month 6 but by Month 12 only remained low in the LNG microspheres group (P < 0.01). The immunostaining of estrogen receptors (ERs) in both the epithelium and stroma and progesterone receptors (PRs) in the stroma was significantly weakened in the LNG microspheres group at Month 6 and was not fully restored at Month 12 (P < 0.01). Metabolic parameters and estrous cycle were not disturbed by local application of LNG microspheres. CONCLUSIONS: In a rat endometriosis model, the suppressive effect of a single intra-cystic injection of LNG microspheres was comparable to that of GnRHa, and was maintained for 1 year. The down-regulation of ERs and PRs might serve as possible mechanism of long-term effectiveness.

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Condition tags

endometriosis

MeSH descriptors

Endometriosis Levonorgestrel Microspheres Microspheres Absorbable Implants Absorbable Implants Animals Animals Biocompatible Materials Biocompatible Materials Biocompatible Materials Body Weight Body Weight Disease Models, Animal Disease Models, Animal Endometriosis Endometriosis Female Female Humans

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Papers in the corpus that this work cites (lower rings, blue) and that cite this one (upper rings, green). Dot size scales with the paper's in-corpus citation count — bigger dot = more influential within the endo/adeno field. Click a dot to open that paper. Outer rings show 2-hop neighbours — papers reached through the immediate citers/citees. [ collapse to 1-hop ]

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