【Animal modeling】-M4 receptor blocker MT3 inhibits form deprivation myopia in guinea pigs

  Objective: To investigate the inhibitory effect of the highly selective M4 receptor blocker MT3 on form deprivation myopia in guinea pigs and its potential mechanism.

  Methods: Three-week-old guinea pigs were randomly divided into three groups: control group, form deprivation group, and form deprivation + MT3 group. Before and after the experiment, strip retinoscopy was used to measure the refraction, A-ultrasound was used to measure the ocular biological parameters, and RT-PCR was used to detect the relative mRNA expression of TGF-β2 in the retina and choroid.

  Results: Compared with the right eye of the control group, the right eye of the guinea pigs in the form deprivation + MT3 group developed (-1.44±0.50) D relative myopia (right eye-left eye), and the vitreous cavity and axial length were respectively prolonged (0.10±0.02 ) mm and (0.14±0.07) mm (P=0.001, P<0.001, P<0.001), but the increase in myopia, vitreous cavity and axial length were significantly smaller than those in the simple form deprivation group (P<0.001, P<0.001). 0.001, P<0.001). Simple form deprivation can down-regulate the relative mRNA expression of TGF-β2 in retina and choroid (P<0.001, P=0.014); while intravitreal injection of MT3 can lead to the relative expression of TGF-β2 in retina and choroid of eyes with form deprivation up-regulated (P<0.001, P<0.001).

  Conclusion: MT3 can inhibit the formation of form deprivation myopia in guinea pigs, which may play its role by up-regulating the mRNA levels of TGF-β2 in the retina and choroid.