Second hand tobacco smoke adversely affects the bone of immature rats

Abstract

OBJECTIVES:To evaluate the influence of secondhand cigarette smoke exposure on longitudinal growth of the tibia of growing rats and some parameters of bone quality.METHODS:Forty female rats were randomly divided into four groups: control: rats were sham exposed; 30 days: rats were exposed to tobacco smoke for 30 days; 45 days: rats were exposed to tobacco smoke for 45 days; and 60 days: rats were exposed to tobacco smoke for 60 days. Blood samples were collected to evaluate the levels of cotinine and alkaline phosphatase. Both tibias were dissected and weighed; the lengths were measured, and the bones were then stored in a freezer for analysis of bone mineral content and mechanical resistance (maximal load and stiffness).RESULTS:Exposure of rats to tobacco smoke significantly compromised bone health, suggesting that the harmful effects may be time dependent. Harmful effects on bone growth were detected and were more pronounced at 60-day follow-ups with a 41.8% reduction in alkaline phosphatase levels (p<0.01) and a decrease of 11.25% in tibia length (p<0.001). Furthermore, a 41.5% decrease in bone mineral density was observed (p<0.001), leading to a 42.8% reduction in maximum strength (p<0.001) and a 56.7% reduction in stiffness (p<0.001).CONCLUSION:Second hand cigarette smoke exposure in rats affected bones that were weaker, deforming them and making them osteopenic. Additionally, the long bone was shorter, suggesting interference with growth. Such events seem to be related to time of exposure.

Cigarette smoke-associated inflammation impairs bone remodeling through NFκB activation

“…Mice exposed to cigarette smoke for three weeks exhibit loss of bone marrow B cells at the Pro-B-to-pre-B cell transition, with a largely reversed outcome after cessation of smoking 6 weeks [ 45 ]. Smoke exposure in immature rats significantly compromised bone health, leading to weaker bone [ 46 ]. There are other possible mechanisms for skeletal damage induced by smoking.…”

Efeitos da inalação da fumaça do tabaco na densidade de mastócitos e no processo de colagenização em tecido gengival de ratas

“…Todavia, a exposição não foi voluntária, realizada por meio de equipamentos, sendo denominada fumaça de segunda mão. Neste contexto, a cotinina é o marcador mais adequado para avaliar o grau de exposição à fumaça do tabaco em humanos, permitindo classificar confiavelmente o grau de exposição em estudo clínico (Chiu et al, 2008) e experimentais (Rosa et al, 2017. Logo, os níveis de cotinina obtidos no plasma dos animais submetidos a fumaça de segunda mão pode ser classificada como passiva.…”

“…Na literatura pesquisada estudos experimentais adotaram valores de referência de cotinina semelhante aos encontrados em humanos para caracterização da exposição passiva (2,1 a 17,5 ng/ml) ou ativa (> 17,5 ng/ml) ( Chiu;Wu & Kuo, 2008;Rosa et al, 2017). Assim esse estudo justifica-se para elucidar os efeitos da inalação da fumaça do tabaco no tecido gengival de ratas, com uso de modelo experimental validados e amplamente aceito na literatura (Wang et al, 1999, Gentner & Weber, 2012Santiago et al, 2017).…”

Chronic Consumption of Alcohol Adversely Affects the Bone of Young Rats

“…Then, the region of interest was delimitated by a square measuring 0.90 cm 2 using the tibial tuberosity as an anatomical landmark. 12 …”

“…The bone extremities rested on two metallic supports that were 25 mm apart, and a progressive load was vertically applied at the center of the posterior surface of the bone at a constant displacement rate of 1 mm/min, until failure. 12 The testing device (EMIC, São José dos Pinhais, PR, Brazil) was equipped with a 500 N load cell, and the load-deflection curve was obtained in real time. The maximal load and stiffness were calculated by a specific software (TESC software, version 13.4, São José dos Pinhais, PR, Brazil).…”