Expression changes of Rhodopsin and recoverin in MNU-induced photoreceptor degeneration in rats

• Main Authors: Wei Jin, Yi-Qiao Xing, Hai-Feng Mei, Wen-Jun Wang, An-Huai Yang
• Format: Article
• Language: English
• Published: Press of International Journal of Ophthalmology (IJO PRESS) 2014-10-01
• Series: Guoji Yanke Zazhi
• Subjects: N-nethl-N-nitrosourea; retina; photoreceptor; apoptosis
• Online Access: http://www.ies.net.cn/cn_publish/2014/10/201410004.pdf
• ISSN: 1672-5123; 1672-5123

AIM: To investigate the time-effect relationship between the expression of rhodopsin and recoverin and photoreceptor damage induced by N-nethl-N-nitrosourea(MNU). <p>METHODS: Thirty-six 7-week old Sprague-Dawley(SD)rats were intraperitoneally injected with MNU(60mg/kg)and were put to death by dislocation of cervical vertebra 6, 12, 24h; 3, 7d after injection(6 per group), respectively. As a control, six rats were injected with phosphate buffer saline(PBS)5mL/kg and sacrificed on d3 after injection. The degree of photoreceptor apoptosis was detected by HE staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling(TUNEL)and transmission electron microscope(TEM)in the right eyes. The mRNA expressions of rhodopsin and recoverin were detected different time after injection by Western blot and immunohistochemical method in the left eyes. <p>RESULTS: The dissolution of photoreceptor nucleus and apoptosis body were first perceived at 12h by TEM; most of cells at outer nuclear layer were presented positive reaction. The apoptotic index reached peak(29.7%±2.3%)at 24h which was coincided with the observation of TEM. The results of immunohistochemistry displayed that rhodopsin and recoverin were on a declining curve with time extension. Furthermore, the results of Western blot indicated that rhodopsin had dramatic decline at 6h after injection(<i>P<</i>0.05), and extremely significant difference comparing to control group after 12h(<i>P<</i>0.01); while recoverin dramatic declined at 12h, and extremely significant difference after 24h(<i>P<</i>0.01). <p>CONCLUSION: 60mg/kg MNU intraperitoneally injection one-time may specifically induce photoreceptor apoptosis, The mechanism of down-regulation of rhodopsin and recoverin may be related to the selected apoptosis of photoreceptors.