RESUMO
Objective To improve the success rate of cerebrospinal fluid (CSF) collection in rats using a modified suction device with negative pressure. Methods A flow regulator was added to the original apparatus to adjust the intensity of negative pressure and to limit the volume of CSF collected each time. A total of 36 male Sprague- Dawley (SD) rats were randomly divided into 3 groups, and the CSF was collected in 3 ways: drawing from the cerebellomedullary cistern via percutaneous puncture, using a suction device with negative pressure and using a modified device. Kruskal-Wallis test was used to evaluate the differences in result between these three methods. Results The modified suction device with negative pressure effectively reduced bleeding. The quality of CSF collected with it was 75％ of 12 rats, significantly higher than that obtained with the original device (33. 3％, P ＜ 0. 01) or drawn from the cerebellomedullary cistern via percutaneous puncture (0％, P ＜ 0. 001). The success rate of qualified sample collection was highly superior to those of previously reported CSF collection methods. Conclusions Our modified suction device for CSF collection is simple and user-friendly, with minimal damage and little bleeding to rats. It can obviously improve the success rate of CSF collection in rats.
RESUMO
Objective To evaluate the inhibitory effect of highly selective M4 receptor antagonist MT3 on the form deprivation myopia in guinea pigs and its potential mechanism. Methods Thirty?two healthy male guinea pigs were ran?domly divided into three groups:control group, form deprivation group, and form deprivation + MT3 group, 8 animals in each group. Refraction was measured by retinoscopy after cycloplegia before and after the experiment. The ocular biological dimensions were measured by A?scan ultrasound. RT?PCR was used to detect the relative expression of TGF?β2 mRNA in the retina and choroid. Results Compared with the right eyes of control group, the right eyes of form deprivation + MT3 group developed relative myopia of -1?44 ± 0?50 D (right?left eye) (P =0?001). The vitreous chamber depth and axial length of the right eyes were significantly prolonged by 0?10 ± 0?02 mm and 0?14 ± 0?07 mm (P<0?001, P<0?001), respectively, but the increases of myopia and axial length were significantly smaller than that of the form deprivation group (P<0?001, P<0?001, P<0?001). Down?regulation of relative mRNA expression of TGF?β2 in retina and choroid was found in the form deprivation group (P<0?001, P =0?014) compared with the right eyes of the control group, while up?regulation of relative mRNA expression of TGF?β2 in retina and choroid was found in the form deprivation + MT3 group ( P<0?001, P<0?001). Conclusions MT3 can inhibit the development of form deprivation myopia in guinea pigs, which may play an important role by the regulation of TGF?β2 mRNA level in the retina and choroid.