The hyperlipidemic Imai rat was originally developed as an animal model of spontaneous hyperlipidemia. We report the natural course of the Imai rat up to 32 weeks of age focusing on renal pathology. The degree of proteinuria, which first appeared at 8 weeks, increased with age, and all Imai rats developed heavy proteinuria (mean, 228 mg/24 h) with impaired renal function (mean BUN, 78.7 mg/dl) at 32 weeks. Histologic changes of the glomeruli were characterized by focal and segmental sclerosis and hyalinosis. Both the percentage of affected glomeruli and the severity of each affected glomerulus were progressively increased with age. The immunofluorescence and electron-microscopic findings were also comparable to those of focal glomerulosclerosis (FGS) in humans. The serum levels of total cholesterol, triglyceride, and phospholipid in Imai rats were significantly higher than those in normal Sprague-Dawley rats at 8 weeks of age, and progressively increased thereafter. The proteinuria, glomerular involvements, and hyperlipidemia were generally less severe in the females than in the males. We conclude that the hyperlipidemic Imai rat, a naturally occurring animal model of FGS, is useful in studying the pathogenesis of FGS and the renal effects of hyperlipidemia in humans.

SARS-CoV2 is a single strand RNA virus member of the type 2 coronavirus family, responsible for causing COVID-19 disease in humans. The objective of this study was to test the ivermectin drug in a murine model of coronavirus infection using a type 2 family RNA coronavirus similar to SARS-CoV2, the mouse hepatitis virus (MHV). BALB/cJ female mice were infected with 6,000 PFU of MHV-A59 (Group Infected; n=20) and immediately treated with one single dose of 500 ug/kg of ivermectin (Group Infected + IVM; n=20), or were not infected and treated with PBS (Control group; n=16). Five days after infection/treatment, mice were euthanized to obtain different tissues to check general health status and infection levels. Overall results demonstrated that viral infection induces the typical MHV disease in infected animals, with livers showing severe hepatocellular necrosis surrounded by a severe lymphoplasmacytic inflammatory infiltration associated with a high hepatic viral load (52,158 AU), while ivermectin administration showed a better health status with lower viral load (23,192 AU; p<0.05) and few livers with histopathological damage (p<0.05), not showing statistical differences with control mice (P=NS). Furthermore, serum transaminase levels (aspartate aminotransferase and alanine aminotransferase) were significantly lower in treated mice compared to infected animals. In conclusion, ivermectin seems to be effective to diminish MHV viral load and disease in mice, being a useful model for further understanding new therapies against coronavirus diseases.

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