Effects of photobiomodulation and swimming on gene expression in rats with the tibialis anterior muscle injury.

The aim of the present study was to evaluate the effects of photobiomodulation (low-level laser therapy (LLLT)) and aquatic exercise on the expression of genes related to muscle regeneration in rats. Wistar rats were divided into five groups: control group (n = 15), non-treated injury group (n = 15), injury+LLLT group (n = 15), injury+aquatic exercise group (n = 15), and injury+LLLT+aquatic exercise group (n = 15). Cryoinjury was performed on the belly of the tibialis anterior (TA) muscle. LLLT was performed daily with an AlGaAs laser (830 nm; beam spot of 0.0324 cm2, output power of 100 mW, energy density of 180 J/cm2, and 58-s exposure time). Animals were euthanized at 7, 14, and 21 days. The TA muscles were removed for gene expression analysis of TGF-ß, Myogenin, and MyoD. The results were statistically analyzed at a significance level of 5%. The cryoinjury increased the expression of genes related to muscle regeneration-MyoD, Myogenin, and TGF-ß-compared to the control group (p < 0.05); the photobiomodulation increased the expression of these genes at day 7 (p < 0.05), decreasing until day 21; and the aquatic exercise increases the expression of the three genes over time. When the two treatments were combined, the expression of the analyzed genes also increased over time. In summary, the results of our study suggest that photobiomodulation (LLLT), when applied alone in cryoinjury, is able to increase the gene expression of MyoD, Myogenin, and TGF-ß at the acute phase, while when combined with aquatic exercises, there is an increase in expression of these genes specially at the long-term treatment.

Association between birth weight, body mass index and IGF2/ApaI polymorphism.

Insulin-like growth factor II (IGF-II) is a polypeptide that plays a key role in mammalian growth, influencing fetal cell division, differentiation, and possibly metabolic regulation. In adult humans, polymorphisms of the IGF2 gene have been associated with predisposition to obesity. In the present study, we tested the association between IGF2/ApaI genotype and Body Mass Index (BMI) in 294 healthy volunteers (95 men and 199 women; 18-30y) and correlated the results with their birth weights (BW) in order to investigate the relationship between this polymorphic site, fetal life and adult BMI. Blood samples were obtained for DNA extraction, PCR and genotyping. The statistical analyses were performed by the Chi-square, Kolmogorov-Smirnov normality, and Tukey post hoc tests. Although the IGF2 genotype was not significantly associated with BMI and/or BW, we observed a statistically significant correlation of 0.33 (p < 0.023) between BW and BMI in GG subjects whose BW was higher than 3.5 kg (n = 47). We hypothesize that high BWs associated with homozygosis for the G allele of IGF2/ApaI is not a null factor and might be associated with predisposition to high BMI in young adults.

Relação entre polimorfismo do gene do hormônio do crescimento e características de precocidade em novilhas da raça Nelore / Relationship between polymorphism of growth hormone and precocity traits in Nellore heifers

Avaliaram-se as relações entre o polimorfismo do gene do hormônio do crescimento (GH) e as características de precocidade, em novilhas da raça Nelore. Amostras de sangue periférico foram obtidas de 181 animais de três rebanhos distintos do estado da Bahia, nas quais foi realizada a extração de DNA e a amplificação por PCR, seguidas por digestão com enzima de restrição AluI. Os fragmentos resultantes da digestão enzimática foram analisados em gel de agarose 2 por cento para determinação dos respectivos genótipos. A frequência do alelo Leu nas amostras analisadas foi estimada em 100 por cento. Em decorrência da alta incidência de homozigose para o alelo Leu, sugere-se que o restriction fragment lenght polymorphism AluI do gene GH não possa ser considerado como marcador molecular para precocidade sexual em novilhas Nelore nesses rebanhos.

The relationships between polymorphism of growth hormone gene (GH) and precocity traits in Nellore heifers were evaluated. A total of 181 animals from three different farms of Bahia state, Brazil, were blood sampled. The DNA of each animal was extracted, amplified by PCR, and digested by "AluI" restriction enzyme, and the resultant fragments were analyzed in 2 percent agarose gel for genotype identification. The frequency of Leu allele in the analyzed samples was estimated in 100 percent. Due to the high incidence of homozygose for the Leu allele, it is suggested that the restriction fragment lenght polymorphism AluI of GH gene can not be considered as a molecular marker for sexual precocity in Nellore heifers of those herds.