ABSTRACT
AIM: To investigate the time - effect relationship between the expression of rhodopsin and recoverin and photoreceptor damage induced by N - nethl - N -nitrosourea ( MNU) . 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. 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 (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.
ABSTRACT
Background Previous studies showed that after herpes simplex virus-1 (HSV-1) infection of the cornea,matrix metallo proteinase-2 (MMP-2) (produced by corneal cells and corneal epithelial cells) plays an important role in the development of HSK.Focal adhesion kinase (FAK)plays an important role on the expression,release and activation of MMPs.This study explored the expressions of MMP-2 and FAK,which induced by HSV-1 infected human corneal epithelial cells.Objective To investigate MMP-2 and FAK expression in HSV-1 infected human corneal epithelial cells.Methods Human corneal epithelial cells were infected with HSV-1 in vitro to establish cell model of viral infection.The expression of MMP-2 and FAK were detected by reverse transcription PCR (RT-PCR),Western blot,immunohistochemical method and immunofluorescence method at 2 hours,20 hours and 40 hours after infection.Results At 2 hours,20 hours and 40 hours after infection,the expressionis of MMP-2 mRNA and FAK mRNA were significantly increased in comparison with uninfected cells (MMP-2 mRNA:Ftime =0.968,P=0.436 ; Fgroup =47.649,P =0.000 ; Fi ion =0.757,P =0.536.FAK mRNA:Ftime =0.658,P =0.631 ; Fgroup =35.182,P=0.000;Finteraction =1.386,P=0.137).Western blot assays showed that there were no significant differences in p-FAK,FAK or MMP-2 expressions between infected cells and control cells after 2 hours (P＞0.05),but the expression levels of infected cells were significantly increased at 20 hours and 40 hours (both at P ＜ 0.05).Immunohistochemistry results showed that longer infection time was associated with an increased number of cells staining for MMP-2,FAK and p-FAK.Conclusions At the initial stage of HSV-1 infected,p-FAK plays an important role in the process of virus invading and MMP-2 activation.