Histopathologic Evaluation of the Substained Delivery of Ovarian Hormones and Neuropeptide Y Antagonist on the Body Weights and Vital Organs of Ovarectomized Rats

The route of administration of ovarian hormones and other biologicals represent a key factor in the treatment, prevention or eradication of different diseases in humans. Many studies have documented that the use of sustained delivery of biologicals is more effective compared to conventional route of administration. To date, the literature is lacking studies that conclusively demonstrate the change on body weights and vital organ morphology associated with sustained delivery of Neuropeptide Y antagonist and estrogen compared to intact and ovariectomized adults as a model. Therefore, the purpose of this study represents a histopathologic evaluation of the sustained delivery of ovarian hormones and neuropeptide y antagonist on the body weight and vital organs of ovariectomized rats. A total of 25 Sprague Dawley rats were obtained and divided into five groups, intact control with ovaries, sham, OVX + estrogen, and NPY antagonist. Animals in three of the five groups were surgically implanted with a TCP drug delivery device loaded with 1.6 mg of estrogen and 1.6 mg of NPY antagonist, and the sham animals were implanted with empty capsules. The capsules were surgically inserted into the muscle adjacent to the six lumbar vertebra. The animals were euthanized at two weeks, post-implantation phases. An analysis of the body weights were compared, and the OVX + estrogen and the OVX + NPY antagonist were similar to the intact control animals. Histopathologic evaluation of the major body organs revealed no histopathological change in the adrenals, spleen, liver, lungs or heart muscles of the intact, OVX, sham and NPY antagonist low and high dose treated animals. The only significant difference was observed in the kidney, where the glomeruli appeared much larger in the estrogen treated animals. Overall conclusion obtained from this study demonstrated that TCPL delivery can be used effectively to administer NPY at sustained level with remarkable reduction in side effects that associated with conventional means.