Sexual behaviour in a murine model of Mucopolysaccharidosis type I (MPS I)

Abstract

Mucopolysaccharidosis Type I (MPS I) is a rare genetic lysosomal storage disease caused by a mutation of IDUA gene. IDUA codes for -L-iduronidase (IDUA), a lysosomal hydrolase that degrades glycosaminoglycans (GAGs): heparan sulphate and dermatan sulphate. GAGs are structural and signalling molecules that have a crucial role in controlling a variety of cell functions and their interaction with extracellular matrix. Because of GAGs widespread action in cellular metabolism, MPS I is a progressive and disabling multisystemic disorder. Nowadays, the therapies availability allowed patients to reach the adult life and the consequences of the disease in their reproductive system is still little known. We aimed to investigate whether IDUA disruption influences sexual behaviour and sexual steroid production in male and female MPS I mice. We used 3 and 6-month-old male and 3-month-old female Idua+/_ and Idua-/- mice to evaluate typical rodent copulatory behaviours. In males we observed the frequency and latency of mounts, intromissions and ejaculations. In females we evaluated the lordosis quotient. We also analysed the locomotor capacity of mice in the open field test, since copulatory behaviour requires mobility. We also quantified steroidal hormonal levels in plasmatic samples. We detected an increase in the latencies of intromissions in male copulatory behaviour of Idua-/- males when compared to Idua+/_. However, the number of intromissions was not statistically different between groups. No parameter of female sexual behaviour was statistically different between control and knockout females. In both sexes, we detected diminished mobility in Idua-/- mice. Plasma hormone levels did not differ between Idua+/_ and Idua-/- mice, both in males and females. We concluded that in the considered time point of MPS I progression, mice are able to perform sexual behaviour, but the male performance may be influenced due to the motor disability predicted to MPS I.