Retinal degeneration mutation in Sftpa1(tm1Kor/J) and Sftpd (-/-) targeted mice

Surfactant proteins are important collectin immune molecules with a wide distribution throughout the body, including the ocular system. Mice with gene deletions for the surfactant protein genes Sftpa1 and Sftpd were observed to have visual impairment and thinning of the outer nuclear layers of the retina. We hypothesized that gene deletion of Sftpa1 and Sftpd (Sftpa1(tm1Kor/J) and Sftpd(-/-)) results in early retinal degeneration in these mice. Sftpa1(tm1Kor/J) and Sftpd(-/-) retinas were evaluated by histopathology and optical coherence tomography (OCT). Retinas from Sftpa1(tm1Kor/J) and Sftpd (-/-) mice showed early retinal degeneration with loss of the outer nuclear layer. After screening of mice for known retinal degeneration mutations, the mice were found to carry a previously unrecognized Pde6b(rd1) genotype which resulted from earlier breeding of the strain with Black Swiss mice during their generation. The mutation was outbred and the genotype of Sftpa1(tm1Kor/J) and Sftpd(-/-) was confirmed. Outbreeding of the Pde6b(rd1) mutation resulted in restoration of normal retinal architecture confirmed by in vivo and in vitro examination. We can therefore conclude that loss of Sftpa1 and Sftpd do not result in retinal degeneration. We have now generated retinal Sftpa1 and Sftpd targeted mice that exhibit normal retinal histology.