A new model for the immobilization of the rat hind limb

An alternative device for the immobilization of the hind limb of the rat was developed to study the effects of chronic disuse on the soleus and tibialis anterior muscles, maintained for 3 weeks in the shortening and the stretching positions, respectively. The proposed device is made of steel mesh and cotton materials, and has some advantages when compared to cast or plaster cast: it is cheaper, lighter (12 g or 4% of the body weight of the rat) and the same unit can be easily adjusted and used several times in the same animal or in animals of similar size. Immobilization is also useful to restrain the movements of the hip, knee, and ankle joints. Male rats (291 ± 35 g and aged 14 ± 2 weeks) were used to develop and test the model. The soleus muscle of 18 rats was maintained in a shortened position for 21 consecutive days and lost 19 ± 7% of its length (P = 0.008) and 44 ± 6% of its weight (P = 0.002) compared to the contralateral intact muscle. No difference (P = 0.67) was found in the stretched tibialis anterior of the same hind limb when compared to the contralateral muscle. No ulcer, sore or foot swelling was observed in the animals. Immobilization was effective in producing chronic muscle disuse in the hind limbs of rats and is an acceptable alternative to the traditional methods of immobilization such as cast or plaster cast.

Alternative genotyping method for the single nucleotide polymorphism A2959G (AF159246) of the bovine CAST gene

The objective of this work was to genotype the single nucleotide polymorphism (SNP) A2959G (AF159246) of bovine CAST gene by PCR-RFLP technique, and to report its use for the first time. For this, 147 Bos indicus and Bos taurus x Bos indicus animals were genotyped. The accuracy of the method was confirmed through the direct sequencing of PCR products of nine individuals. The lowest frequency of the meat tenderness favorable allele (A) in Bos indicus was confirmed. The use of PCR-RFLP for the genotyping of the bovine CAST gene SNP was shown to be robust and inexpensive, which will greatly facilitate its analysis by laboratories with basic structure.