engleski

Increased bone structure in animals with perinatally altered serotonin metabolism

In mammals, serotonin (5HT) is present both in the brain and peripheral tissues. In the brain, serotonin acts as a key regulator of serotonergic outgrowth and synaptogenesis during development and later it assumes the function of a neurotransmitter, while peripheral serotonin is involved in the regulation of gastrointestinal and cardiovascular functions and platelet aggregation. Additionally, serotonin is considered to be a negative regulator of bone remodeling in which osteoblasts and osteoclasts maintain a fine balance between bone formation and resorption. There is a growing evidence for the involvement of central and peripheral 5HT in the regulation of bone tissue, but the interplay between the two compartments in maintaining bone mass still remains to be elucidated. In order to study the effects of the two compartments, we examined bone structure in rats perinatally treated with tranylcypromine (TCP), an irreversible inhibitor of monoamine oxidase. Rats were treated with 2mg/kg TCP or saline from gestational day 12 until postnatal day 21. In adult animals, 5HT concentration was significantly increased in the peripheral compartment and significantly decreased in the central compartment, in comparison to the saline treated rats. Femurs were collected on postnatal day 70 and cortical and trabecular bone parameters were examined by SkyScan 1076 micro CT device. In comparison to the saline treated rats, TCP-treated rats displayed significantly increased trabecular bone volume, trabecular number and connectivity density, along with decreased cortical volume and thickness. Smaller, more compact bones with increased trabecular structure in animals with decreased brain 5HT concentrations may suggest a more prominent role of the central 5HT compartment in bone maintenance.

serotonin; tranylcypromine; bone remodelling; rat model

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