PMC

Twice weekly cages are changed and replaced with a new Nestlet (A), the Nestlet is shredded by the rat prior to forming the nest (B), and then the rat spends time resting in the formed nest (C).

Ambulatory time was significantly lower for isolation reared rats treated with Nestlets (column 4) compared to untreated isolation reared rats (column 3) and not different from group reared rats (column 1) or group reared rats treated with Nestlets (column 2). Average±SEM.,*P<0.05, ** P<0.01, ***P<0.001.

(A). 92% of group reared rats healed well (n = 12, column 1, 2B, and top row 2C), 12% of isolation reared rats healed well (n = 8, middle column 2B, and middle row 2C), and 64% of isolation reared rats treated with Nestlets healed well (n = 11 see third column 2B, and bottom row 2C).* P<0.05, ** P<0.01, *** P<0.001.

For each rat, the number of pixels comprising the width of the maximum gap of unhealed tissue was normalized to the width of its back. The average normalized pixels of unhealed tissue were significantly greater for the isolation-reared rats (middle column) compared with both the group-reared rats (first column) and the isolation reared rats treated with Nestlets (third column). Average±S.E.M., *p<.05, ** P<0.01.

Rats treated with Nestlets had significantly higher gene expression compared to isolation reared rats without Nestlets for cfos and junb (compare columns 3 and 4 for these genes). Gene expression of rats treated with Nestlets returned to that of group reared rats for these genes (compare columns 1 and 4 for cfos and junb). Group reared rats treated with Nestlets showed an increase in these genes above the expression level for group reared rats not treated with Nestlets (compare columns 1 and 2) even though there was no additional benefit to their wound healing (since wound healing was maximal for the group reared rats without the Nestlets). Average±SEM, *p<0.05, **p<.01, ***p<.001.

Panel A shows an example of wound healing over six weeks from weaning (PN20 to PN62) in the four conditions examined. Panel B shows that group reared rats had significantly better healing compared to isolation reared rats by 21 days post burn injury, while Nestlet and oxytocin treated rats showed similar healing to group reared rats by 28 days post burn injury. The difference between Nestlet treated, oxytocin treated, and group reared rats compared to isolation reared rats continued until 42 days post burn injury. Average±S.E.M., *p<.05, ** p<0.01, ***p<0.001.