Spontaneous Histologic Lesions of the Adult Naked Mole Rat (Heterocephalus glaber)

Abstract

Naked mole rats (NMRs; Heterocephalus glaber) are highly adapted, subterranean, eusocial rodents from semiarid regions of the eastern horn of Africa and the longest-living rodent known with a maximum life span of up to 30 years. They are a unique model for aging research due to their physiology, extreme longevity, and, when compared to mice and rats, resistance to cancer. Published surveys of disease in NMRs are sparse. Captive colonies in zoological collections provide an opportunity to monitor spontaneous disease over time in a seminatural environment. This retrospective study describes common lesions of a zoo population over a 15-year period during which 138 adult NMRs were submitted for gross and histologic evaluation. Of these, 61 (44.2%) were male, 77 (55.8%) female, 45 (32.6%) died, and 93 (67.4%) were euthanized. The most frequent cause of death or reason for euthanasia was conspecific trauma (bite wounds) and secondary complications. Some common histologic lesions and their prevalence were renal tubular mineralization (82.6%), hepatic hemosiderosis (64.5%), bite wounds (63.8%), chronic progressive nephropathy (52.9%), and calcinosis cutis (10.1%). In sum, 104 (75.4%) NMRs had more than one of the most prevalent histologic lesions. No malignant neoplasms were noted; however, there was a case of renal tubular adenomatous hyperplasia with nuclear atypia and compression that in rats is considered a preneoplastic lesion. This retrospective study confirms the NMR's relative resistance to cancer in spite of development of other degenerative diseases and highlights the utility of zoological databases for baseline pathological data on nontraditional animal models.

Comparative genetics of longevity and cancer: insights from long-lived rodents

“…The naked mole rat ( Heterocephalus glaber ) and the blind mole rat ( Spalax ehrenbergi ) represent two striking examples of animals that live in protected environments and display extreme longevity and resistance to cancer 12, 34–36 . The naked mole rat is a eusocial rodent that lives in large colonies in Africa 37 , while the blind mole rat is a solitary animal found in the Middle East 38 .…”

Molecular evolution of the hyaluronan synthase 2 gene in mammals: implications for adaptations to the subterranean niche and cancer resistance

“…There has been considerable interest in the ability of NMRs to resist cancer [1,2], and recently, a mechanism involving the production of a high molecular mass hyaluronan (HMM-HA) has been proposed [3]. Hyaluronan (HA) is a glycosaminoglycan and its presence in a variety of tissues and the extracellular matrix has been linked to many cellular processes, such as cell division, motility and morphogenesis [4], and also implicated in the development of some cancers [5].…”

INK4 locus of the tumor-resistant rodent, the naked mole rat, expresses a functional p15/p16 hybrid isoform

“…Additionally, despite being kept in captivity since 1974, there has been no reported incidence of neoplasia in these animals (2,3). Naked mole rats remain healthy until almost the end of their lives, showing resistance to multiple age-related diseases (4).…”