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Shunt treatment at two postnatal ages in hydrocephalic H-Tx rats quantified using MR imaging
H C Jones1, N G Harris, R W Briggs
1Department of Pharmacology and Therapeutics, University of Florida, Gainesville, USA.
Insights
Hydrocephalus in H-Tx rats was effectively treated with ventriculosubcutaneous shunts, significantly reducing ventricle size and improving cortical thickness. Shunt placement timing did not impact these key outcomes.
Area of Science:
- Neuroscience
- Developmental Biology
- Medical Imaging
Background:
- Inherited hydrocephalus in H-Tx rats presents in late gestation.
- Hydrocephalus leads to progressive ventricular enlargement and potential neurological deficits.
Purpose of the Study:
- To evaluate the efficacy of ventriculosubcutaneous shunting in treating inherited hydrocephalus in H-Tx rats.
- To compare the effects of early versus late shunt placement on hydrocephalus progression.
Main Methods:
- Hydrocephalic H-Tx rat pups received ventriculosubcutaneous shunts at different ages (3-6 days or 8-12 days).
- Multislice proton magnetic resonance (MR) imaging was used for quantitative analysis of ventricular volume and cortical mantle thickness.
- Shunt-treated, untreated hydrocephalic, and age-matched control rats were imaged at various time points.
Main Results:
- Untreated hydrocephalic pups showed linear ventricular volume increase (52 µL/day).
- Shunted pups exhibited significantly reduced ventricular volumes (approx. 20% of untreated hydrocephalic rats) and increased cortical mantle thickness compared to untreated pups.
- No significant difference in post-shunt ventricular volume was observed between early and late shunt groups.
Conclusions:
- Ventriculosubcutaneous shunt treatment effectively reversed hydrocephalus in H-Tx rats, as evidenced by MR imaging.
- Shunt placement at both early and late stages normalized ventricular volume and cortical thickness.
- While MR imaging indicated structural improvements, cellular-level normal morphology may not be fully restored, even with early intervention.
Abstract:
The H-Tx rat has inherited hydrocephalus with an onset in late gestation. Ventriculosubcutaneous shunts were placed in a group of hydrocephalic pups at 3-6 days after birth and in another group at 8-12 days after birth. Multislice proton magnetic resonance (MR) images were taken of shunt-treated pups at 7, 14, or 21 days and of age-matched control and untreated hydrocephalic rats and were subjected to quantitative analysis. Some rats were also imaged before surgery. The volume of the ventricles of untreated hydrocephalic pups increased linearly with age at a rate of 52 microliters/day. The ventricles of shunted pups were reduced from the preshunt condition and were around 20% of age-matched hydrocephalic rats. There was no significant difference in the post-shunt volume between early and late shunt groups. The cortical mantle thickness in both groups of shunt-treated rats was significantly thicker than in untreated pups and close to that of control rats. It is concluded that shunt treatment at both ages reversed the hydrocephalus as measured from MR images, although other evidence from fixed brains suggests that normal morphology may not be achieved at the cellular level even for early shunts.