The study was conducted to evaluate the prophylactic antiviral efficacy of pyridinium compounds containing the quinoxaline and oxazine core against the bovine leukaemia virus (BLV). The experiment involved four groups of guinea pigs (five individuals in each group). Animals of the 1st and 2nd groups were intraperitoneally injected with compounds of 3,4-dihydroquinoxalin-2-one (20 mg/kg) and 3,4-dihydro-2H-1,4-benzoxazin-2-one (15 mg/kg), respectively. Two hours after the administration of the drugs, the animals of these groups, as well as individuals of the 3rd group, were intraperitoneally infected with lymphocytes isolated from the blood of a cow sick with leukaemia. Guinea pigs of the 4th group remained intact (negative control). On the 30th, 90th, and 180th days after inoculation with the virus, blood was collected for diagnostic and biochemical studies. Infection of the guinea pigs with BLV has caused a significant transformation: the concentration of liver enzymes (AST and ALT) has increased by 1.29–1.35 times, that of alkaline phosphatase by 1.45 times, and that of creatinine by 1.53 times, while the urea level has decreased by 1.16 times, total bilirubin by 1.44 times, and cholesterol level by 1.34 times. The carriage of the virus was confirmed by the immunofluorescence method in 100% of animals and the antibody titer averaged 1:512 by the end of the experiment. The use of the studied drugs contributed to the normalization of biochemical parameters by the 180th day. The best effect was observed when using the 3,4-dihydro-2H-1,4-benzoxazin-2-one compound. The individuals of this group exhibited only a slight (compared to the negative control) trend towards an increase in the concentration of ALT (by 1.06 times), creatinine (by 1.16 times), and total protein (by 1.1 times). Diagnostic studies have revealed a decrease in the viral load after treatment with the 3,4-dihydroquinoxalin-2-one derivative (virus titer 1:32–1:64) and the absence of antigen in the blood after treatment with the 3,4-dihydro-2H-1,4-benzoxazin-2-one compound.
Novikova et al. (Fri,) studied this question.