The comparison of the phototropic response of the mouse rod photoreceptors at different PN ages revealed that the amplitude of the response increases with the age of the sample. The analysis performed on that data was focused on the comparison of the values and it shows some limits when it comes to providing a reliable value of the actual shift of the photoreceptors that could be compared with previous and future results. The acquisition of the image sequences from freshly isolated retinae (at 15, 17 and 19 PN ages) with Near-Infrared light microscopy and their comparison was performed for my Master Thesis at the University of Illinois at Chicago, under the direction of Doctor Xincheng Yao. This work aims to overcome the limits of the data analysis of my previous master thesis. The analysis of the image sequences will be performed in order to provide an amplitude value that can realistically quantify the movement of the photoreceptors. Moreover, the analysis will also compare the stimulated and the non- stimulated areas in order to observe the difference between the responses. By focusing the analysis on the amplitude of peaks values, it was possible to obtain an average value that is much closer to the actual movement of the rod photoreceptors and it can be compared with literature values (0.1micrometers for the adult wild type mouse). As far as concerns the comparison of the stimulated and the non-stimulated areas, the analysis did not provide satisfying results. Only for one distribution, the central peaks showed a more phototropic behavior than the peaks in the lateral (and non-stimulated) areas. This can be attributed to the characteristics of the mouse retina, to an insufficient number of samples and mainly to the in vitro conditions of the experiments. Further studies on the biophysical mechanisms underlying TRP could provide major information on the functioning of rod photoreceptors, which are less studied than cones (mainly to the smaller dimensions) and also, it could ultimately provide a non- invasive biomarker for the early detection of retinal degeneration.
Il paragone delle risposte allo stimolo luminoso dei bastoncelli nelle retine di topo a diverse età ha permesso di concludere che l’ampiezza della risposta dipende dall’età della retina analizzata. L’analisi effettuata su questi dati aveva lo scopo di evidenziare le differenze nelle diverse distribuzioni ma i valori calcolati non sono un indice attendibile per quanto riguarda l’effettivo movimento dei fotorecettori. L’utilizzo di Near-Infrared light microscopy su retine di topo appena isolate mi ha permesso l’osservazione e la registrazione della risposta dei bastoncelli. Le sequenze di immagini sono state acquisite durante la mia permanenza alla University of Illinois at Chicago, sotto la guida del Dottor Xincheng Yao e il loro paragone è stato oggetto della tesi magistrale che ho conseguito la scorsa estate. In questa dissertazione analizzerò le immagini in modo da ottenere l’effettiva ampiezza del movimento dei bastoncelli alle diverse età. Inoltre, l’analisi si concentrerà sul paragone tra l’area della retina stimolata e le aree non stimolate in modo da rilevare eventuali differenze nelle risposte. Eseguendo un’analisi basata sui picchi di ampiezza nelle imagini, è stato possibile ottenere dei valori di ampiezza molto simili ai valori trovati in letteratura (0.1micrometri per il topo adulto). Per quanto riguarda il paragone delle aree stimolate e non stimolate, l’analisi è stata inconcludente. Sono in un caso i picchi nella zona centrale (stimolata) hanno mostrato un comportamento più fototropico dei picchi nelle aree laterali (non-stimolate). Questo risultato può essere dovuto alle caratteristiche delle retine di topo, ad un insufficiente numero di campioni oppure alle condizioni in vitro dell’esperimento.
Quantification of transient retinal phototropism in developing mouse retina
MANEO, VITTORIA
2018/2019
Abstract
The comparison of the phototropic response of the mouse rod photoreceptors at different PN ages revealed that the amplitude of the response increases with the age of the sample. The analysis performed on that data was focused on the comparison of the values and it shows some limits when it comes to providing a reliable value of the actual shift of the photoreceptors that could be compared with previous and future results. The acquisition of the image sequences from freshly isolated retinae (at 15, 17 and 19 PN ages) with Near-Infrared light microscopy and their comparison was performed for my Master Thesis at the University of Illinois at Chicago, under the direction of Doctor Xincheng Yao. This work aims to overcome the limits of the data analysis of my previous master thesis. The analysis of the image sequences will be performed in order to provide an amplitude value that can realistically quantify the movement of the photoreceptors. Moreover, the analysis will also compare the stimulated and the non- stimulated areas in order to observe the difference between the responses. By focusing the analysis on the amplitude of peaks values, it was possible to obtain an average value that is much closer to the actual movement of the rod photoreceptors and it can be compared with literature values (0.1micrometers for the adult wild type mouse). As far as concerns the comparison of the stimulated and the non-stimulated areas, the analysis did not provide satisfying results. Only for one distribution, the central peaks showed a more phototropic behavior than the peaks in the lateral (and non-stimulated) areas. This can be attributed to the characteristics of the mouse retina, to an insufficient number of samples and mainly to the in vitro conditions of the experiments. Further studies on the biophysical mechanisms underlying TRP could provide major information on the functioning of rod photoreceptors, which are less studied than cones (mainly to the smaller dimensions) and also, it could ultimately provide a non- invasive biomarker for the early detection of retinal degeneration.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/150966