In vitro evaluation of the effects of tobramycin and parathyroid hormone on mesenchymal stem cells.

: Approximately 7.9 million bone fractures occur every year in the United States, with an estimated cost of $70 billion. It is estimated that 5-10 percent of patients will develop infections or delayed healing following orthopedic surgery. The probability of osteomyelitis is related to the severity of trauma and infection is most frequent after high velocity, open injuries with skin loss. Complications with bone healing and antibiotic drug-resistance increases morbidity and costs associated with osteomyelitis are estimated at $15,000-$30,000 per incident. Traditional osteomyelitis treatment often requires additional surgery and systemic antibiotics that are harmful, burdensome, and costly. There is limited evidence in the literature examining the effects pharmacological agents tobramycin (TOB) and parathyroid hormone (PTH) have on the mesenchymal stem cells (MSCs) that differentiate into many cell types. The purpose of this investigation was to evaluate the in vitro dose-dependent effects of TOB and PTH on mesenchymal stem cells. MSCs were treated for periods of 24, 48 and 72 hours in the presence of TOB and PTH. Following incubation, MSCs were examined for cellular morphology, viability, proliferation, and damage. Our results show an increase in morphological changes following treatments with both PTH and TOB which are confirmed by decreases in cellular protein concentration. Are results also indicate PTH acts as an essential factor in mesenchymal development and may control differentiation into osteogenic or chondrogenic lineage. Development of targeted delivery of PTH and TOB to a fracture may be effective at treating both infection and bone loss.