Strain differences in the distribution of NDP‐ase labelled microglia in the normal rabbit retina

Abstract

Nucleoside diphosphatase (NDP-ase) labelled microglial cells were examined in retinas of three strains of rabbit, the New Zealand White (albino), the Canberra Half-Lop, and the Dutch Belted. The distribution in the nerve fibre and inner plexiform layers was similar in all strains. However, the outer plexiform layer (OPL) of Dutch-Belted rabbits was completely covered with a population of non-overlapping NDP-ase positive microglia while the OPL of New Zealand White and Half-Lop strains contained only occasional isolated cells. In the Dutch-Belted strain the area covered by the processes of each cell was less in central than peripheral retina where the cell density was lower. In the central retina of the New Zealand White and Half-Lop strains the cells covered an area similar to that of peripheral Dutch-Belted cells, suggesting that they were at a low density and there was no hidden population of cells. This finding was confirmed by Griffonia simplicifolia lectin labelling. Therefore the data is consistent with there being a strain variation in OPL microglia. The intensity of NDP-ase label in the IPL and GCL was less in the New Zealand White and Half-Lop strains and although the intensity increased after retinal injury it never reached that of the Dutch-Belted retinas. These variations in the intensity of NDP-ase expression and the localization of microglial cells may be important in inflammation and also for CNS function.

Microglial responses to focal lesions of the rabbit retina: Correlation with neural and macroglial reactions

“…We have recently demonstrated that different strains of rabbit have quite different numbers of NDP-ase positive microglia in the OPL, ranging from a complete coverage to only rare cells, as in the strain used in the current study (Humphrey and Moore, 1995). Labelling with Griffonia simplicifolia lectin produced similar results but we do not know whether these are independent markers and therefore, although unlikely, there could be a population of microglia that do not express NDP-ase.…”

Microglial cells in the retina ofCarassius auratus: Effects of optic nerve crush

“…In 77% of the retinas analysed, there were regions where microglial cells clustered together, covering all layers of the retina. These accumulations have been described by others (Humphrey and Moore, 1994, 1995; reviewed by: Kreutzberg, 1996, Moore and Thanos, 1996) and have been called microglial nodes (Fig. 2F).…”

Circumferential migration of ameboid microglia in the margin of the developing quail retina

“…This pattern of distribution is similar to that in different species of adult mammals (Boycott and Hopkins, 1981;Hume et al, 1983;Sanyal and De Ruiter, 1985;Boya et al, 1987;Penfold et al, 1991;Provis et al, 1995;Humphrey and Moore, 1995;Thanos et al, 1996). The retinal microglia have an exogenous origin (Ashwell, 1989;Ashwell et al, 1989;Schnitzer, 1989;Diaz-Araya et al, 1995a,b;Navascués et al, 1995Navascués et al, , 1996.…”